SUMMARY

Indolent systemic mastocytosis (ISM) is a subtype of mastocytosis that is characterized by a

mild proliferation and accumulation of pathological mast cells in extracutaneous tissues, with

or without cutaneous involvement. Accumulation and degranulation of mast cells in the bone

may cause symptoms of bone involvement, the most important symptoms being fragility

fractures and osteoporosis.

These patients are generally treated with bisphosphonates, according to the guidelines for the

regular, postmenopausal osteoporosis population with increased fracture risk. However,

considering the different pathophysiological mechanism causing the symptoms and the

different composition of the ISM population compared to the postmenopausal population,

questions on the effectiveness of bisphosphonates as a treatment for patients with ISM and

osteoporosis and/or fragility fractures can be raised.

This study is the largest study to evaluate the effectiveness of bisphosphonates in 50 ISM

patients with symptoms of bone involvement with regards to fracture rate, bone mineral density

(BMD) and zCTx scores during five years of follow-up. Bisphosphonates significantly

increased the lumbar BMD and decreased bone turnover, considering the decrease in zCTx

scores. A decrease in fracture rate prior to and after treatment was found when assuming that

fractures prior to treatment are detected within two years. Interpretation of this fracture rate is

difficult, since a proper control group is lacking. Therefore, final conclusions on the

effectiveness of bisphosphonates as a treatment for patients with ISM and bone involvement in

the form of fragility fractures and osteoporosis cannot be made. However, considering the large

number of fractures in this patient population, proper treatment is necessary and future

randomized studies are highly recommended to further evaluate this treatment option.

SAMENVATTING

Indolente systemische mastocytose (ISM) is een subtype van mastocytose. Het wordt

gekarakteriseerd door een milde proliferatie en opeenstapeling van pathologische mestcellen in

extracutane weefsels, met daarnaast nog eventuele betrokkenheid van het cutane weefsel. De

ophoping en degranulatie van mestcellen in het bot kan symptomen als het ontstaan van laag

energetische fracturen dan wel osteoporose veroorzaken.

Deze patiënten worden over het algemeen, in navolging van de richtlijnen van de reguliere,

postmenopauzale osteoporose populatie met een verhoogd fractuurrisico, behandeld met

bisfosfonaten. Echter, gelet op de verschillen in onderliggende pathofysiologie en de

verschillen in samenstelling van de populatie, is het de vraag of deze behandeling wel effectief

is voor de ISM populatie.

Deze studie is de grootste studie die de effectiviteit van bisfosfonaten evalueert. 50 patiënten

met ISM en botbetrokkenheid met betrekking tot fractuurfrequentie, botmineraaldichtheid

(BMD) en zCTx scores zijn gevolgd gedurende een follow-up van vijf jaar. Bisfosfonaten

verhoogden de lumbale BMD en zorgden voor een verlaagde bot turnover, wat af te lezen is in

een daling van zCTx scores. De fractuurfrequentie nam af na behandeling als aangenomen

wordt dat fracturen voor start van behandeling binnen twee jaar gedetecteerd worden.

Interpretatie van deze gegevens is gecompliceerd, aangezien er geen goede controlegroep

beschikbaar is. Samenvattend kunnen we geen definitieve conclusies trekken wat betreft de

effectiviteit van bisfosfonaten in de behandeling van patiënten met ISM en LE fracturen in de

vorm van LE fracturen en osteoporose. Desalniettemin behoeft deze groep wel goede

behandeling gelet op het grote aantal fracturen. Daarom is vervolgonderzoek in de vorm van

een randomized clinical trial sterk aanbevolen.

3

CONTENTS

English and Dutch summary p. 2

Abbreviations p. 4

Introduction p. 5

Materials and methods p. 7

Results p. 11

- Flowchart

- Baseline results

- General results

- Fractures

- Lumbar BMD

- Femoral BMD

- zCTx

Discussion p. 21

Conclusion p. 24

References p. 25

Appendices p. 27

- Appendix 1

- Appendix 2

- Appendix 3

- Appendix 4

- Appendix 5

- Appendix 6

4

ABBREVIATIONS

SM = systemic mastocytosis

BMD = bone mineral density

CTx = cross-linked telopeptide of type I collagen

HE = high energetic

ISM = indolent systemic mastocytosis

IQR = interquartile range

LE fractures = low energetic fractures/ fragility fractures

MPR = medication possession rate

zCTx = age and sex linked z score of CTx

5

INTRODUCTION

Mast cells are commonly known for their role in allergic reactions. They can be activated by

various triggers, though usually they are activated after cross-linking of antigens to IgE attached

to the Fc epsilon receptor on the mast cell membrane, causing subsequent degranulation of the

cell. The release of mediators such as histamine and heparin causes a wide variety of symptoms,

e.g. flushing, pruritis, urticaria, nasal congestion and hypotension. (1)

Mastocytosis is a rare disease. The systemic variant of the disease has an estimated prevalence

of 1 in 10,000 (2,3). It is characterized by abnormal proliferation and accumulation of

pathological mast cells in various tissues of the body (4-6). Common sites of accumulation are

the skin, bone marrow, liver, spleen, lymph nodes and the gastro-intestinal system.

Due to pathological abnormalities of mast cells in patients with mastocytosis, stem cell factor

is not required for mast cell differentiation, activation and survival. The most common mutation

that causes this abnormal cell function is the D816V mutation of the KIT gene. This mutation

is found in approximately 80% of patients with systemic mastocytosis. (1,7)

The WHO distinguishes seven types of mastocytosis. Cutaneous mastocytosis, systemic

mastocytosis (SM) and mast cell tumours are the three main groups. Cutaneous mastocytosis,

with characteristic urticaria pigmentosa laesions, is restricted to the skin. There are two types

of mast cell tumours, mast cell sarcoma and extracutateous mastocytoma. Systemic

mastocytosis (SM) presents itself in extracutaneous tissues and is diagnosed when a patient

meets the major criterion and at least one minor criterion or three minor criteria. SM may

present itself with or without cutaneous involvement.

The major criterion for systemic mastocytosis is met when multifocal dense aggregates of mast

cells, with more than 15 cells per aggregate, are found in an extracutaneous tissue. The four

minor criteria are respectively more than 25% of morphologically abnormal mast cells in bone

marrow or extracutaneous tissues, detection of a D816V Kit mutation in laesional tissue or in

the peripheral blood, the expression of CD25 and/ or CD2 by KIT+ mast cells, and serum

baseline tryptase levels higher than 20 ng/mL. (4)

Depending of the severity of proliferation and organ involvement, SM can be further

differentiated in indolent systemic mastocytosis (ISM), smouldering systemic mastocytosis

(SSM), aggressive systemic mastocytosis (ASM) and systemic mastocytosis with an associated

clonal haematological non-mast-cell-lineage disease (SM-AHNMD).

The vast majority (90%) of patients with SM suffers from indolent systemic mastocytosis. ISM

is characterized by a mild proliferation of mast cells, an indolent course and a good prognosis,

with a normal life expectancy. The percentage of mast cells in the bone marrow is usually below

5%. (7,8)

The clinical presentation of ISM is varies, partly due to the variation in sites of accumulation

of mast cells. Patients may suffer from symptoms like flushing, gastro-intestinal complaints or

anaphylaxis (due to various triggers, of which stings of wasps and bees are most life

threatening).

One of the extracutaneous sites in which the disease manifests itself is the bone. Manifestation

of ISM in the bone can cause a variety of symptoms, ranging from bone pain to osteoporosis,

osteosclerosis and fragility fractures (fractures caused by low energetic trauma).

Osteoporosis, defined by a decreased bone mineral density (BMD) of a T-score of < -2.5 in the

lumbar spine or the hip, is a frequent manifestation in patients with ISM. So far, the reported

6

prevalence of osteoporosis in patients with ISM ranges from 18 to 31%. (7, 9-12) One study

showed a high prevalence of 54% of osteoporotic fractures in ISM patients (10).

Osteoporosis is normally found in postmenopausal women as a result of hormonal changes.

However, the mastocytosis population with osteoporosis or low energetic (LE) fractures has a

different composition than the ‘regular’ osteoporosis population. Thus far, studies show that

approximately 50% of the patients with osteoporosis or fragility fractures were male.

Furthermore, this bone involvement regularly manifest itself in patients under the age of 50.

(10,11)

There is increasing evidence that the mediators released by mast cells mediators interfere with

the natural mechanism of demolition and construction of the bone, causing bone loss and

therefore contributing to the development of osteoporosis. (10,11,13)

According to Dutch guidelines, patients in the postmenopausal osteoporosis population with a

high fracture risk are generally treated with bisphosphonates plus calcium and vitamin D, in

order to increase bone mineral density and therefore decrease the chance of fragility fractures.

(14) Bisphosphonates have a high affinity for bone mineral, resulting in a selective uptake by

the osteoclasts. Furthermore, they have a strong inhibitory effect on osteoclasts. Therefore they

are highly suitable for the treatment of osteoporosis in postmenopausal women. (15)

Considering the assumed differences in underlying pathophysiological mechanisms of the

occurrence of osteoporosis and/ or fragility fractures in the postmenopausal and mastocytosis

populations questions can be raised about the effectiveness of bisphosphonates as a treatment

for patients with SM with bone involvement. Since mast cell release is local, the subsequent

damage to the bone is local as well. General inhibition of osteoclasts caused by bisphosphonates

may not be as effective as it is in the postmenopausal population in the prevention of fragility

fractures.

So far, only small studies have looked at the effect of bisphosphonates as a treatment of

osteoporosis. These studies had only a small number of participants and/or a short duration of

follow-up. (9,16-21)

The two studies with the largest number of participants provided data of respectively 25 patients

with a follow-up of only 1 year and 9 patients with an average duration of follow-up of 65

months. (9,16) In these studies bisphosphonates did appear to be effective in increasing BMD

and the prevention of fragility fractures.

Since Groningen is the national centre for expertise on mastocytosis, we have a large population

of patients with mastocytosis and osteoporosis and/ or fragility fractures who have been treated

with bisphosphonates. Furthermore, the duration of follow-up is relatively high, compared to

previous studies. This allows us to give a more elaborate assessment of the effectiveness of

bisphosphonates in preventing the occurrence of fragility fractures and in increasing the bone

mineral density of patients suffering from indolent systemic mastocytosis.

7

MATERIALS AND METHODS

This retrospective cohort study evaluates the effectiveness of bisphosphonates on preventing

fragility fractures and increasing bone mineral density (BMD) after five years of treatment in

patients suffering from indolent systemic mastocytosis (ISM) and osteoporosis and/ or fragility

fractures.

Subjects

For this study the list of patients of all 693 patients who had visited the UMCG because of a

suspicion of mastocytosis was used. Furthermore, a database containing information on 53

ISM patients who were known to have used bisphosphonates prior to 2011 was used. This

database was last updated in 2011. Using the patient list of 693 patients we were able to identify

an additional 11 patients that had been treated with bisphosphonates.

Patients known to have used bisphosphonates at the present or in the past were approached to

participate in this research.

The medical ethical committee judged that all necessary guidelines were met. Subsequently,

patients were approached. They were asked for their informed consent for using data from their

medical records. Furthermore, they were asked for informed consent for requesting a history of

drugs supplied by their pharmacist. This only concerned drugs relevant to the study

(bisphosphonates, calcium, vitamin D). Finally, they were asked to report if, when and under

which circumstances they ever fractured any bones.

Patients who did not initially respond to the send letter were contacted by telephone. The

pharmacists of patients who agreed to participate were contacted by telephone and provided

with a copy of the patient’s informed consent. Correspondence with the medical ethical

committee, patients and pharmacists can be found in appendix 1-3.

Available data (medical records, previous response to a questionnaire about fractures) of

patients who were deceased were used. No informed consent was asked from relatives of the

deceased and no further data were requested from either pharmacists or relatives.

Patients diagnosed with ISM who were treated with bisphosphonates were included,

irrespective of start of bisphosphonate treatment prior to or after ISM diagnosis. Patients who

started treatment in or after January 2011 were excluded based on a too short duration of follow-

up. Patients who were given mast cell eradication therapy, e.g. interferon alpha, imatinib or

cladribine, before or during bisphosphonate treatment, were also excluded. If ISM progressed

to SSM during the first five years of bisphosphonate treatment, their follow-up data was

excluded. However, their baseline data were included. The BMD and CTx (cross-linked

telopeptide of type I collagen, a bone resorption marker) data of one transwoman were excluded,

since BMD and CTx are sex related. Her fracture outcomes were included.

Treatment characteristics and baseline data

Moment of start of treatment was determined by data in patient’s medical records and the data

provided by the pharmacists. The data provided by the pharmacists were considered to be

leading, unless this data was incomplete or unclear.

The number and types of bisphosphonates used per patient were noted, as well as the average

duration of treatment, adverse events and reasons for terminating treatment.

Data from the medical records (in case of intravenous administration) and data provided by the

pharmacists were used to determine duration of treatment and medication possession rate

8

(MPR). MPR was determined for the first five years of treatment, since the evaluation of

treatment was also based on this period. MPR of the period after these 5 years was not

determined. If patients were not treated for five years, the MPR for the duration of treatment

was evaluated. Based on previous studies with bisphosphonates in osteoporotic women patients

with a MPR of ≥ 80% were considered to be compliant(22-25). Patients with a MPR ≥ 80% and

a duration of treatment of ≥ five years were defined as having been treated per protocol.

The collected baseline data can be found in Table 1 of the results. Indication of treatment was

assessed; were patients started on bisphosphonates shortly after LE fractures were detected or

shortly after low BMD values were measured? Parameters of disease activity were measured in

blood (tryptase) or urine (MH, MIMA). Fractures were inventoried by using patients response

to the questionnaire and data in their medical records. If digital medical records were not

elaborate enough or were lacking paper medical records were requested. BMD was measured

with the use of DEXA scans. zCTx scores prior to bisphosphonate treatment were noted. zCTx

levels are the age and sex matched scores of CTx levels measured in the blood. Only CTx levels

measured in the afternoon were used, given the circadian pattern of this parameter. Furthermore

use of H1 and H2 antagonists as well as calcium and/or vitamin at start of bisphosphonate

treatment was noted. Also smoking and alcohol habits at baseline were inventoried. Patients

who had given up smoking for at least a year at baseline were considered to have quit. Alcohol

abuse was defined as >2 units of alcohol per day, alcohol intolerance was noted if patients

reported discomfort after consumption of small amounts of alcohol. Patients were screened for

the presence of co-morbidities and use of medication (for ≥ 3 months) that influence the bone

metabolism using information in their medical records. Co-morbidities include hypo- and

hyperthyroidism, celiac disease, renal insufficiency, hypogonadism, premature menopause and

acromegaly. Medications include anti-epileptics, corticosteroids (inhaled or systemic,

excluding eye drops), thiazides and furosemide.

Measurement and statistical analysis of follow-up data

During follow-up fractures, BMD and zCTx were assessed. Disease activity was not assessed

during follow-up, for bisphosphonate treatment does not interfere with this and therefore no

changes were expected.

Fractures were noted at three moments in time. A history and total number of fractures at start

of treatment, occurrence and total number of fractures within the first year of treatment and

occurrence and total number of fractures up to 5 years of follow-up (with a range of 4 to 6

years). In the latter group a differentiation between patients who were and were not treated per

protocol was made.

Fractures were assessed using medical records, patient’s response to the questionnaire and the

results of DEXA scans and vertebral fracture assessment (VFA). The vertebral fractures in the

reports had been assessed by a nuclear medicine physician, using the criteria by Genant. These

criteria consider a reduction of at least 20% in anterior, middle, and/or posterior height (relative

to the same or adjacent vertebrae) accompanied by a reduction in area of at least 10% to be a

fracture.(26) In case of doubt or incomplete reports we reassessed the scans using the same

criteria.

Fractures were classified as vertebral and non-vertebral fractures. Furthermore, they were

divided as high (HE) and low energy (LE) fractures. LE fractures were defined as fractures as

a results of a mechanical impact that would normally not result in a fracture. (27)

The fractures in the first year of treatment were recorded separately, for the duration of

bisphosphonate treatment would then have been too short in order to be able to effectively in

9

prevent fractures. Furthermore, some patients did not have a recent DEXA scan and VFA at

start of treatment, meaning fractures detected during the first year of treatment could also have

occurred prior to start of treatment.

A survival analysis (Kaplan Meier curve) of LE vertebral fractures was made to evaluate the

moment of occurrence of the first fracture during follow-up. The fractures that occurred in the

first year of treatment were excluded in this analysis, for previously explained reasons. If

fractures were noted by the patient, the date the patient mentioned was used for the survival

curve. If the fracture was measured on a DEXA scan, but had not been observed before, the

date of the DEXA scan was used as the moment of fracture. If patients did not have a DEXA

scan in the range of 4 to 6 years after start of treatment the date of the last DEXA scan prior to

the 4 to 6 year period was used as the moment of loss to follow-up, even if DEXA scans after

more than 6 years showed absence of fractures. This was done to prevent the occurrence of a

positive bias in our data. Patients who showed no fractures at DEXA scans in the range of 4 to

6 years were all recorded as a censored case at 5 years exactly. Patients who showed fractures

on the DEXA scan between 5 and 6 years were all recorded to have fractures at 5 years exactly.

This was done because if the exact dates would be used an unrealistic drop would be seen at

the end of the curve, due to the great number of drop-out cases before the full 6 years.

Changes of BMD between baseline and follow-up were measured at the lumbar spine and the

proximal femur. For BMD at baseline a range of 1 year prior to and 1 year after start of

bisphosphonate treatment was used. For follow-up the range of 4-6 years was used. BMD was

measured both in T and Z scores, as well as in absolute numbers (g/cm3). T scores were

considered to be the most important outcome measure of the three, since these scores are most

commonly used in clinical care. Lumbar BMD was considered to be a more important outcome

measure than femoral BMD, since osteoporosis has more often been found in the lumbar spine

than in the femur in the ISM population, meaning the mastocytosis is presumably more active

at this site(11).

For assessment of lumbar and femoral BMD changes, plots of T and Z scores were made. The

number of measurements for all outcome units were inventoried. Some patients had

measurements at baseline and between 4 to 6 years of follow-up. Others only had measurements

at one of the two moments of measurement. Medians and interquartile ranges (IQR) were given

of the group with both measurements and of the group as a whole (in other words, including

patients with only one measurement). Results of BMD were found to be non-parametric, hence

two-tailed Wilcoxon Matched-Pairs Signed-Ranks Tests were performed to determine whether

changes in BMD prior and after treatment were significant. Analysis of absolute scores was not

performed here, for these scores are age and sex linked, therefore overall median and IQR scores

are not of additional value, as opposed to Δ scores of these absolute numbers.

Due to the low number of patients in our population and the wide variety in T and Z scores at

baseline, medians may be deceptive. Therefore these analyses (median, IQR, Wilcoxon) were

also performed on the Δ T, Z and g/cm3 scores.

Furthermore, subanalyses of median, IQR and Wilcoxon Matched-Pairs Signed-Ranks Tests

on T scores and Δ T scores of lumbar BMD were performed for the subgroups men and women,

per protocol and not per protocol, start of treatment prior to 2005 and after 2005, the presence

or absence of lumbar fractures prior to treatment and the presence or absence of lumbar fractures

during follow-up. These subanalyses were only performed on T scores of lumbar BMD, since

this outcome measurement was considered to be most important. The baseline variables zCTx

(for compliance), tryptase (disease activity), BMI (general condition) and femoral BMD

10

(general level of osteoporosis) of these groups were compared to see if there were any large

differences between the groups that could explain differences in effectiveness.

The differentiation between start of treatment prior to 2005 and after 2005 was made because

in 2004 changes in the settings of the DEXA scan equipment were made, which may potentially

influence the results.

Finally, changes in zCTx were assessed. zCTx levels should decrease when adequate

bisphosphonate treatment is used. Due to the rapid decrease of zCTx shortly after start of

treatment only zCTx levels before start of treatment (max. 1 year) were used as baseline

variables. In case of doubt over the exact date of start of treatment and multiple available zCTx

data in this period, the oldest zCTx measurement was taken, to be sure that the values represent

the bone turnover prior to treatment.

11

RESULTS

Flowchart

Out of the 693 patients known in the UMCG, 243 patients had ISM. A total number of 64

patients were identified as ISM patients were/ had been treated with bisphosphonates. Five of

these patients were deceased. A total number of 59 patients was approached by mail. 17 non-

responders were approached by phone in an attempt to increase the response rate. We managed

to obtain informed consent of 53 patients. Four patients were excluded based on the moment of

start of treatment (after 1-3-2011). Two patients were excluded because on closer evaluation

their did not suffer from ISM but smouldering or aggressive systemic mastocytosis. Two

patients were excluded because they received mast cell eradication therapy. Aside from these

45 patients, the additional 5 deceased patients were included in the study, resulting in a total

number of 50 included patients.

Figure 1: flowchart in- and exclusion

Patients approached by mail

n=59

Non-responders to mail and subsequent

phone approach

n=6

Patients with obtained

informed consent

n=53

Exclusion

Start of treatment after 1-3-2011 (n=4)

Diagnosis other than ISM (n=2)

Current mast cell eradication therapy (n=2)

Patients after exclusion

n=45

Deceased patients included in the study

n=5

Included patients

n=50

Adult patients with ISM

n=243

12

Baseline results

Table 1 shows the baseline characteristics of the 50 ISM patients we were able to include. They

were all treated with bisphosphonates for their osteoporosis and/ or fragility fractures. Baseline

was defined as the moment of start of treatment with bisphosphonates. Numbers are given in

means or medians, depending on whether or not the data were normally distributed.

At start of treatment the patients had an average age of 55 years. A relatively equal number of

men and women was included. The vast majority of the women was postmenopausal at start of

treatment. On average, women were also older than men when they started treatment, 58.8 years

compared to 49.9 years. Low BMD scores were a more common indication for start of treatment

then the detection of fragility fractures. 26% and 12% of patients had a history of respectively

low or high energetic vertebral fractures at start of treatment, in 12% of the patients a vertebral

fracture was detected during the first year of treatment. Lumbar and femoral BMD had a median

T score of respectively -2.65 and -1.30.

Urticaria pigmentosa was present in the majority of patients. H1 and H2 antagonists were used

in a minority of patients at start of treatment, which may indicate that osteoporosis and fragility

fractures are an early presentation of ISM because regular treatment had not been initiated yet.

Calcium and/ or vitamin D was more commonly used at start of treatment, which is in

accordance with the guidelines.

Co-morbidities influencing and medications interfering with bone metabolism were found

rather frequently in this population.

Variable Participants

(n=50)

Age at start of treatment (yr) mean (sd) 54.7 (11.1)

Gender n (%)

Male

Female

Transwoman

23 (46%)

26 (52 %)

1 (2%)

Menopausal status in women n (%)*

Premenopausal

Postmenopausal

2 (8.3%)

24 (91.7%)

Indication for treatment n (%)

Low BMD

#

34 (68%)

16 (32%)

Urticaria pigmentosa n (%)

Absent

Present

20 (40%)

30 (60%)

BMI mean (sd)

<20 n (%)

20-25 n (%)

25-30 n (%)

30-35 n (%)

>35 n (%)

N of patients missing

25.6 (4.0)

4 (11%)

12 (33%)

15 (42%)

5 (14%)

0 (0%)

14

Parameters of disease activity median

(iqr)

Tryptase

MH

51.6 (24.9 – 94.0)

347 (261 – 587)

4.4 (2.8 – 7.1)

13

MIMA

Fracture history n (%)

Low energetic, vertebral

High energetic, vertebral

Low energetic, other

High energetic, other

13 (26%)

3 (6%)

4 (8%)

27 (54%)

Fractures during first year of treatment n

(%)

Low energetic, vertebral

High energetic, vertebral

Low energetic, other

High energetic, other

5 (10%)

0 (0%)

0 (0%)

1 (2%)

Lumbar BMD

T score median (iqr)

Z score median (iqr)

-2.65 (-3.35 to -1.80)

-1.65 (-2.68 to -0.60)

Femoral BMD mean (sd)

T score median (iqr)

Z score m mean (sd)

-1.30 (-1.90 to -0.55)

-0.57 (0.87)

zCTx mean (sd) 1.0 (1.8)

Use of H1 antagonists n (%)

Yes

No

N patients missing

17 (36.2%)

30 (63.8%)

3

Use of H2 antagonists n (%)

Yes

No

N patients missing

15 (32.6%)

31 (67.4%)

4

Use of calcium and or vitamin D n (%)

Yes

No

N patients missing

31 (67.4%)

15 (32.6%)

4

Alcohol n (%)

Intolerance

Tolerance

Abuse

N patients missing

5 (10.6%)

38 (80.9%)

4 (8.5%)

3

Smoking habits n (%)

Yes

No

Quit

N patients missing

17 (35.4%)

23 (47.9%)

8 (16.7%)

2

History of normal TSH n (%)

Yes

Not measured

Aberrant

29 (59.2%)

19 (38.8%)

1 (2%)

25(OH)Vit3 levels prior to treatment

median (iqr)

N patients missing

58.5 (42.5-98)

32

Co-morbidities that interfere with bone

metabolism n (%)

14

Yes

No

N patients missing

11 (22.4%)

38 (77.6%)

1

Medication used for > 3 months that

interferes with bone metabolism n (%)

Yes

No

N patients missing

7 (14.2%)

42 (85.7%)

1

*One transwoman was excluded from this analysis

Table 1: Baseline characteristics

15

General results

The mean duration of treatment was 6.97 years, with a standard deviation of 2.98 years.

The patients used a total of 6 different bisphosphonates. Risedronate was used most often (32

patients), followed by alendronate (n=20), zolendronate (n=8), ibandronate (n=6), etidronate

(n=3) and pamidronate (n=3).

34 patients used one type of bisphosphonates for the entire duration of treatment. 11 patients

used 2 different types, 3 patients used 3 different types and 1 patient used 4 different types.

18 patients were treated per protocol. Of the 32 patients who were not treated per protocol, 4

had both a duration of treatment of less than 5 years as well as an MPR below 0.80. 8 had only

a duration less than 5 years and 20 had an MPR below 0.80. In 6 of the 24 patients with a MPR

below 0.80 we were unable to determine the MPR. This was due to pharmacists who could not

retrieve data from the required period (n=5) or due to an unwilling pharmacist (n=1).

Reasons for termination of treatment varied, but were often unknown. Recorded reasons for

termination were the patient’s own initiative or compliance (n=2), duration of treatment (n=2)

(the physician questioned the effect of bisphosphonates after years of treatment), normal BMD

after treatment (n=1), occurrence of a new fracture during follow-up (n=1).

There were no patients where other treatments to improve BMD and prevent fractures, e.g.

denosumab and teriparatide, were used prior to bisphosphonate treatment or in the five years of

follow-up. Some patients did use these medications in a later stadium. Two patients did receive

oestrogen treatment for their osteoporosis prior to bisphosphonate treatment.

Serious adverse events were not reported. 3 patients suffered from musculoskeletal pains,

possibly as a result of the treatment. 1 patient suffered from fever and bone pain after

intravenous administration of zolendronate. 3 patients experienced “trouble” at intake of

bisphosphonates.

16

Results of fractures

Prior to start of treatment 75 high energetic (HE), and 7 low energetic (LE) non-vertebral

fractures were reported in respectively 27 and 4 patients. The HE fractures were mainly

childhood fractures. 4 HE and 28 LE vertebral fractures were found in respectively 3 and 13

patients. In the first year of treatment 1 HE non-vertebral fracture and 1 HE vertebral fracture

were noted. In 5 patients a total of 10 LE vertebral fractures was detected.

Treatment with bisphosphonates was always initiated within one year after detection of a LE

fracture.

In the remaining 1-6 years of follow-up 1 HE vertebral fracture was noted. 7 HE non-vertebral

fractures were noted in 6 patients. 22 LE vertebral fractures were detected in 14 patients. A

survival curve can be seen in Figure 2. No LE fractures of other bones were reported. 14 patients

were lost to follow-up. The remaining 22 patients showed no fractures at DEXA scans with

vertebral fracture assessment in the 4-6 year follow-up period.

Of the 14 patients with LE vertebral fractures in the 2 to 6 years follow-up period, 5 were treated

per protocol, 9 were not treated per protocol. The 5 patients who were treated per protocol had

a total of 9 fractures; one patient had 4 fractures, one 2, and the other three patients had 1

fracture each. The 9 patients who were not treated per protocol accounted for the remaining 13

fractures. Five patients had 1 fracture, four patients had 2 fractures each.

The average time of follow-up after which the first fracture in the per protocol group was

detected was 4.38 years. In the group not treated per protocol this was 2.37 years.

Figure 2: Survival analysis LE vertebral # after 1 year of treatment.

17

Results lumbar BMD

Plots of T and Z score, seen in Figure 3, showed an increase of BMD after treatment. The data

were all slightly left skewed, therefore non parametric tests were performed.

T score lumbar: baseline - 5 years

0 1-6

-4

-2

0

2 p=0.001

moment of measurement

T s

co

re lu

mb

ar

Z score lumbar: baseline - 5 years

0 1

-6

-1

4p=0.000

moment of measurement

lum

bar

Z s

co

re

Figure 3: plots of change of T and Z score of lumbar BMD

In the total population of 50 patients, 23 patients had T score and Z score and 25 patients had a

g/cm3 score measurement at baseline and in the 4-6 years range of follow-up. An additional 9

(T and Z) and 10 (g/cm3) patients only had a measurement at baseline and 8 patients only had

a follow-up measurement (all units). The remaining 10 (T & Z) and 7 (g/cm3) patients lacked

measurements at both measurement periods.

Analysing T and Z scores of patients with results at both moments of measurements resulted in

a significant increase of medians of -2.70 to -2.50 in T score and -2.00 to -1.10 in Z score after

5 years of follow-up.

Analysis of all T and Z scores of all patients also showed an increase in median score. Wilcoxon

analysis could not be performed here, since not all data were paired.

Baseline After 5 years P value Wilcoxon

T score, both

measurements

-2.70 (-3.50 to -1.80) -2.50

(-2.90 to -0.50)

0.000

Z score, both

measurements

-2.00 (-2.80 to -1.30) -1.10

(-2.30 to -0.20)

0.000

T score, all patients -2.65 (-3.35 to -1.80) -2.10

(-2.80 to -0.60)

Not applicable

Z score, all patients -1.65 (-2.68 to -0.60) -1.10

(-2.30 to -0.20)

Not applicable

Table 2 : Changes in lumbar BMD prior to and after treatment.

Analysis of Δ T, Z and g/cm3 scores resulted in a significant increase of lumbar BMD for all

three outcome measures. Median ΔT score increase was 0.65 (0.10-1.00) with a P value of

0.000, Z score 0.70 (0.33–1.10) with a P value of 0.000, g/cm3 0.08 (0.01- 0.12) with a P value

of 0.001.

For the subanalyses, plots of lumbar T scores for the different subgroups can be found in

appendix 4. Median and IQR outcomes mentioned in Table 3 are based only on the patients

18

with both baseline and follow-up data. The results of the Wilcoxon tests are only based on the

patients with both baseline and follow-up data.

A table with results of the several baseline characteristics of the subgroups can be found in

Appendix 5. Significant differences were found in tryptase levels between patients treated per

protocol and not treated per protocol (24.9 vs. 70.4, p-value 0.001). Furthermore significant

differences were found in BMI in patients with or without lumbar fractures during follow-up

(26.4 vs 25.4, p-value 0.000).The other differences in baseline values were not significant.

Table 3 shows that the differences in T scores at baseline and at 5 years of follow-up were

significant in all subgroups, except for the patients who started treatment prior to 2005.

Based on the medians of T scores, the subgroups in which patients were male, not treated per

protocol, started treatment after 2004, had lumbar fractures prior to treatment or during follow-

up, appeared to have higher increase in T scores of lumbar BMD. However, the medians of

delta T scores showed higher increase in the subgroups women, treated per protocol and no

lumbar fractures prior to treatment. Furthermore, remarkably no increase in median T score of

the group with start of treatment ≤2004 to treatment and in the group without lumbar fractures

prior to start of treatment was seen, whereas Δ median T scores were significantly increased.

N T score

median (IQR)

baseline

T score median

(IQR) follow-up

Δ T score

median

(IQR)

P-value

Men 12 -2.75

(-3.65 to -1.85)

-2.15

(-2.87 to -0.80)

0.40

(0.25 – 1.00)

0.005

Women 11 -2.70

(-3.40 to -1.50)

-2.50

(-3.20 to -0.20)

0.80

(0.25 – 1.08)

0.029

Per protocol 8 -2.70

(-3.48 to -1.58)

-2.55

(-2.80 to -0.75)

0.90

(0.05 – 1.00)

0.042

Not per protocol 15 -2.80

(-3.50 to -2.00)

-1.90

(-3.10 to -0.20)

0.50

(0.10 – 1.38)

0.004

Start of

treatment ≤

2004

5 -2.80

(-3.90 to -1.65)

-2.80

(-3.20 to -1.10)

0.40

(0.10 – 0.95)

0.068

Start of

treatment >

2004

18 -2.65

(-3.48 to -1.95)

-1.85

(-2.83 to -0.43)

0.70

(0.10 – 1.10)

0.002

Lumbar # prior

to of treatment

6 -1.90

(-3.70 to -1.73)

-1.20

(-2.00 to -0.73)

0.30

(0.00 – 0.93)

0.026

No lumbar #

prior to

treatment

17 -2.80

(-3.45 to -2.40)

-2.80

(-3.15 to -0.05)

1.00

(0.85 – 1.30)

0.005

Lumbar # in

follow- up

9 -2.80

(-3.70 to -1.00)

-1.80

(-3.15 to -0.05)

0.90

(0.05 – 1.45)

0.025

No lumbar # in

follow up

14 -2.65

(-3.13 to -1.95)

-2.50

(-2.95 to -0.73)

0.40

(0.10 – 1.00)

0.006

Table 3: T scores of lumbar BMD in subgroups

19

Results femoral BMD

Of the total 50 patients, 22 patients had T scores at baseline and in the 4-6 years range of follow-

up, 23 had Z scores at both time points, 25 had scores in (g/cm3). An additional 10 (T and

g/cm3) and 9 (Z) and 10 patients only had a measurement at baseline and 8 patients only had a

follow-up measurement (all units). The remaining 10 (T &Z) and 7 (g/cm3) patients lacked

measurements at both time points.

Plots of femoral T and Z score show a relatively stable femoral T and Z score before and after

treatment, as can be seen in Appendix 7.

Analysing T and Z scores of patients with results at both baseline and after 5 years resulted in

an increase of medians of -1.20 to -1.05 in T score and -0.90 to -0.50 in Z score after 5 years of

follow-up. The increase in Z score was significant, the increase in T score was not significant.

Analysis of all T and Z scores of all patients (including those with only 1 measurement) also

showed an increase in median score.

Baseline After 5 years P value Wilcoxon

T score, patients with

both measurements

-1.20 (-1.93 to -0.45) -1.05 (-1.73 to -

0.30)

0.081

Z score, patients with

both measurements

-0.90 (-1.3 to -0.20) -0.50 (-1.20 to 0.10) 0.019

T score, all patients -1.10 (-1.90 to -0.50) -1.05 (-1.73 to -

0.30)

Not applicable

Z score, all patients -0.60 (-1.10 to -0.25) -0.50 (-1.20 to 0.10) Not applicable

Table 4: Changes in femoral BMD prior to and after treatment.

Absolute increase of Δ femoral BMD score (in g/cm3) was 0.015 (-0.01 to 0.50) with a P-value

0.001. No significant increase in Δ median T and Z scores was found, with results of 0.15 (-

0.10 to 0.33), P value 0.081 and 0.10 (-0.10 to 0.30), P value 0.081 respectively.

20

Results zCTx

Of 50 patients, 15 patients had a zCTx measurement prior to start of treatment and in the 4-6

years range of follow-up. An additional 12 patients only had a zCTx measurement prior to

treatment and 13 patients only had a follow-up measurement. The other 10 patients lacked zCTx

scores at both measurement periods.

A plot was made of the change in zCTx values over time. 3 patients showed an increase in

zCTx, the other 12 patients had decreasing values. The 3 patients with an increase in zCTx were

all not treated per protocol.

Change in zctx: baseline - 5 years

0 1

-2

0

2

4 p=0.020

moment of measurement

zC

Tx

Figure 4: Plot of change in zCTx (n=15)

Median and interquartile range of the baseline and follow-up measurements were respectively

0.58 (-0.44 to 2.21) and -0.97 (-1.28 to 0.58), showing a descrease in zCTx after treatment. A

2-tailed Wilcoxon matched-pairs signed-ranks test analysis showed a significant P-value of

0.020.

Analysis of all 27 and 28 zCTx values prior and after treatment also showed a decrease in zCTx

scores after treatment, substantiating this finding. Median and IQR scores were respectively

0.51 (-0.43 to 2.21) and -0.97 (-1.55 to -0.24).

21

DISCUSSION

This is the first study evaluating the efficacy of treatment with bisphosphonates in patients with

ISM suffering from fragility fractures and/or osteoporosis. Considering the low prevalence of

ISM, we were able to evaluate a large group of patients with ISM and osteoporosis for a

relatively long duration of follow-up. High numbers of fragility fractures were found prior to

and after treatment. Lumbar BMD increased after treatment, femoral BMD did not.

We managed to obtain 5 year follow-up fracture data of 36 patients and complete baseline plus

5 year follow-up data of BMD of 23 patients, which makes this the largest study on the

effectiveness of bisphosphonates in patients with ISM with bone involvement.

Our study showed 28 LE vertebral fractures in 13 patients prior to start of treatment, compared

to 22 LE vertebral fractures in 14 patients during follow-up. Assuming that fractures are

detected within two years after the event the fracture rate has lowered from on average 14 per

year in 50 patients to 5.5 fractures per year in 36 patients. However, it has to be taken into

account that DEXA scans were not made regularly in all patients before detection of fractures.

Fractures may have been present for a much longer period of time. Also, the reduction in

fracture rate might also be due to other factors; patients may have altered their lifestyle after

previous fractures or diagnosis of osteoporosis.

Even though patients who were treated per protocol did not have less fractures per patient during

follow-up than the group who was not treated per protocol, fractures in this group did occur at

a later moment during follow-up. This indicates that bisphosphonates are effective in

postponing fractures.

Great effort was made to determine the MPR of the patients, for this is highly important in

evaluating the effectiveness of treatment and the subsequent outcomes of treatment. The

proportion of patients that was treated per protocol was, with 18 out of 50 patients, relatively

low. We think that this is an underestimation of the true proportion of patients treated per

protocol. Partly, this was due to incomplete or absent information provided by the pharmacists,

which made determining the (exact) MPR impossible. Furthermore, patients may have been

provided with bisphosphonates by other pharmacists or hospitals without our knowledge,

resulting in an underestimated MPR. However, compliance to oral bisphosphonates may be low

either way. A previous study in a postmenopausal osteoporotic population showed only 43% of

persistence to therapy after 1 year of treatment with various oral bisphosphonates (28). The

uncertainties in determining the MPR and thus the treatment per protocol may have been of

influence on the small differences found between the per protocol group and not per protocol

group, both in fracture outcomes as well as in BMD data.

The decrease in 12 of 15 of zCTx scores after treatment does imply a relatively good compliance

to therapy. In 3 patients an increase in zCTx was seen. These patients were not treated per

protocol. In 2 patient increase of zCTx was most likely caused by non-compliance, 1 patient

had a continuously low zCTx score, before and during treatment, which increased slightly.

Increase in median T score lumbar BMD was significant. The increase in Δ median T scores

was even higher. Therefore bisphosphonate treatment appears to be effective in increasing

BMD, though a control group is lacking.

A limitation of the lumbar BMD data that may have influenced our results is the fact that we

did not exclude vertebrae that were fractured before treatment of during follow-up when

calculating lumbar BMD. Patients with lumbar fractures during follow-up had a higher increase

in BMD scores than the patients without fractures. This is most likely due to the increase in

BMD due to the fractures and not due to the bisphosphonate treatment. Correction was

22

considered for fractures occurred during follow-up. However, not all original images of the

scans were available. Therefore we decided to use a consistent method not correcting for these

scores. In case of lumbar fractures prior to treatment we did not consider correction of these

data to be necessary, as we thought fractures prior to treatment will not influence the effect of

the bisphosphonates on BMD, as long as fractures do not worsen. However, based on the results

this may have had influence after all as the Δ median T score increased more in the group with

no fracture prior to treatment. Perhaps increase in BMD was not possible in this extent in the

group with a fracture, as the BMD at baseline was already increased due to these fractures.

Changes in femoral BMD were small and not significant. However, strikingly, generally

patients did not suffer from symptoms at the femur either, not at baseline and not after treatment,

in contrast to the lumbar spine region. Femoral BMD T scores were not in the osteoporotic

range of T scores below -2.50 and only one patient reported a hip fracture, which was the result

of a HE trauma.

Only one study previously discussed prevalence of LE fractures in ISM patients (10). This study

was also performed in the UMCG, so there is overlap in the patients evaluated in these studies.

Patients already using bisphosphonates at moment of ISM diagnosis were excluded. In this

study a prevalence of 37% of LE fractures was found, 62% of which were LE vertebral

fractures. This prevalence is comparable to the ratio of patients with or without LE fractures

found during our follow-up period in our study, with fractures in 14 out of 36 patients (39%).

Proper comparison to a control group of ISM patients with bone involvement without treatment

was not possible. In order to put our results slightly into perspective we have made a comparison

with two large studies in postmenopausal osteoporosis populations. (29,30) These studies aimed

to evaluate the effect of alendronate and risedronate on the occurrence of fractures and change

in BMD compared to placebo.

In both studies follow-up was 2 to 3 years. In the first study, at baseline approximately 20% of

patients suffered from fractures. Occurrence of new vertebral fractures during these periods of

follow-up varied largely, with 3.2% in one study and 18.1% in the other, compared to 6.2% and

29% in controls treated with placebo, though in the latter study only patients with a history of

vertebral fractures at baseline (3 to 4 fractures on average) were included which might indicate

that this population is more prone to have fractures in follow-up as well. (29,30) Our study

showed new vertebral fractures in 39% of patients in the five year period of follow-up. After 2

to 3 years the percentage of survival in our survivalcurve is approximately 80 to 90%, which

is comparable to the second study. However, in our study, at baseline, 28% of patients showed

vertebral fractures. Therefore, our population appears to be much more prone to the

development of vertebral fractures than the postmenopausal osteoporosis population.

Concerning lumbar BMD: the increase in BMD was only given in percentages in above

mentioned studies, with increases of approximately 7% and 8% after 2 or 3 years of treatment.

This data is comparable with the increase in median T score in our population after 5 years of

treatment. However, the Δ median T score of our population showed a higher increase. These

differences in our results can be explained by the large variety of BMD between the patients.

This variety has a relatively large influence on the results, due to the low number of patients.

Unfortunately these Δ scores cannot be compared to the postmenopausal studies, for absolute

increase in T scores were not given in these studies, so Δ scores cannot be calculated.

Furthermore, the large variation between changes in median T scores and ΔT scores makes

interpretation of the increase in BMD shown in our data more difficult. In contrast to our study,

these two postmenopausal studies did find an increase in femoral BMD.

23

Overall comparison to the postmenopausal population tells us that bisphosphonates appear to

increase lumbar BMD in our ISM population to a comparable extent as they do in the

postmenopausal population. However, fracture rate is higher in our population.

Finally, the reported number of adverse events in our population was low, but is likely to be

underestimated. Since patients were usually only seen in the UMCG once every one or two

years, or even less regularly, day-to-day care was provided by the GP or other hospitals.

Adverse events may have only been reported there. Considering that a large proportion of

patients switched type of bisphosphonate at least once may indicate that patients may have

suffered from adverse events more often than is known to us.

For future research a prospective study on the effectiveness of bisphosphonates would be useful

in order to obtain a more complete dataset than we managed to obtain in this study. We are

planning to conduct a international multicentre randomized controlled trial that compares the

effects of bisphosphonates to the effect of denosumab in patients with ISM and bone

involvement. Denosumab is a treatment option that is increasingly used in the postmenopausal

osteoporosis population, that may also be of value in this population. The use of two groups

ISM will also simplify the interpretation of the data for changes in outcome measurements can

be compared to a similar patient population.

24

CONCLUSION

We evaluated a relatively large group of ISM patients with bone involvement in the form of

osteoporosis and/ or fragility fractures.

Assuming LE fractures prior to treatment are detected within two years of the event, we can

conclude that the fracture rate of LE vertebral fractures decreases after treatment with

bisphosphonates. Furthermore a significant increase lumbar BMD was found. No significant

changes in femoral BMD were found, though no LE fractures or low (T score < -2.5) BMD

were detected at the femur either. It is important to realise that an increase in lumbar BMD is

only relevant when this prevents the occurrence of fragility fractures.

Final conclusions on the effectiveness of bisphosphonates as a treatment in patients with ISM

and fragility fractures and/or osteoporosis cannot be made, since a control group with similar

patient characteristics is lacking.

Considering the large proportion of fragility fractures prior to treatment and during follow-up,

this population is clearly in need of proper treatment. Therefore future research is required.

25

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28

APPENDICES

Appendix 1

Letter to METc

Geachte heer/ mevrouw,

Bij dezen verzoeken wij u te beoordelen of het volgende onderzoek wel of niet WMO-plichtig

is.

Momenteel zijn wij bezig met een retrospectieve studie naar het effect van bisfosfonaten op

osteoporose en/of laag energetische fracturen in patiënten met mastocytose.

Bij patiënten met mastocytose wordt verondersteld dat de osteoporose en/ of laag energetische

fracturen veroorzaakt worden door de release van mediatoren afkomstig uit mestcellen.

Vanwege de veronderstelde verschillen met de reguliere osteoporose populatie

(postmenopauzale vrouwen) is het van belang om de effectiviteit van bisfosfonaten in deze

patiëntenpopulatie te evalueren.

Voor dit onderzoek maken wij gebruik van een database met patiëntgegevens van patiënten die

bij ons onder behandeling zijn of zijn geweest en van wie bekend is dat zij momenteel of in het

verleden met bisfosfonaten zijn behandeld.

Er wordt gebruik gemaakt van een subpopulatie uit de generieke mastocytose database, en het

gaat om ongeveer 60 patiënten. Baselinegegevens en follow-up gegevens zijn sinds het begin

van de bisfosfonaatbehandeling bijgehouden. De patiënten zijn op zijn vroegst in 1995

begonnen met de behandeling. De duur van follow-up varieert, aangezien niet alle patiënten

meer in het UMCG onder behandeling zijn. Meestal betreft het een periode van omstreeks tien

jaar. Bijgehouden variabelen zijn onder andere parameters van ziekte-activiteit, resultaten van

botdichtheidsmetingen en uitslagen van biopten.

Bisfosfonaten worden veelal langdurig (gedurende jaren) voorgeschreven. Om de

therapietrouw van deze patiënten zo goed mogelijk in kaart te brengen willen wij deze patiënten

aanschrijven om toestemming vragen om de data van afhalen en hoeveelheid afgehaalde

medicijnen bij hun apothekers op te vragen. De medicatie betreft kalktabletten, vitamine D

tabletten en bisfosfonaten, zoals alendronaat.

In afwachting van uw antwoord, bij voorbaat hartelijk dank.

Hoogachtend,

Namens Dr. J.N.G. Oude Elberink, internist-allergoloog, hoofd mastocytose werkgroep

Merel Onnes

Student-onderzoeker

29

Appendix 2

Letter to patients

Geachte heer / mevrouw,

U heeft mastocytose en u bent daarvoor bij ons in het UMCG onder behandeling of u bent dat

in het verleden geweest. Het UMCG is sinds 2015 officieel een Expertise centrum, erkend door

de Nederlandse Federatie van Universitair Medische Centra (NFU).

Een van de redenen dat wij van de overheid deze erkenning hebben gekregen is dat wij naast

het bieden van een optimale behandeling aan mensen met mastocytose ook veel onderzoek doen

naar de verschillende aspecten van dit ziektebeeld.

Waarom wij sturen wij u deze brief?

1. Algemeen

In het kader van het onderzoek naar mastocytose zouden wij graag enkele gegevens uit uw

medisch dossier gebruiken, zoals labwaarden en resultaten van botdichtheidsmetingen. Wij

mogen deze gegevens volgens de huidige wetgeving gebruiken zonder hiervoor speciaal

toestemming van de betreffende persoon nodig te hebben. De wetgeving wordt echter steeds

strenger en daarom vinden wij het netter om u officieel om toestemming te vragen om deze

gegevens te gebruiken. Voor u betekent dit dat wij uw gegevens, uiteraard volledig

geanonimiseerd, gebruiken om meer kennis en inzicht te vergaren in de verschillende aspecten

van dit ziektebeeld, om uiteindelijk voor nog betere behandelingsmogelijkheden te kunnen

zorgen. Dit kost u geen extra bezoeken of onderzoeken.

2. Specifiek: onderzoek naar botontkalking

Bijna de helft van de mensen met mastocytose heeft ernstige osteoporose (botontkalking), wat

dus veel meer is dan in de algemene bevolking.

Mensen met botontkalking zonder mastocytose worden behandeld met medicijnen die wij

bisfosfonaten noemen. Of deze medicijnen ook goed werken bij botontkalking door

mastocytose is nooit onderzocht. Wij zijn nu aan het bekijken of deze medicijnen goed werken.

Voor betrouwbare conclusies hebben wij gedetailleerde informatie nodig. Ten eerste is het

belangrijk zo precies mogelijk de dosering en de start- en stopdatum te weten Hiervoor zijn

gegevens van de apotheek nodig en daarvoor hebben wij uw toestemming nodig. Ten tweede

is het belangrijk precies te weten of en wanneer u iets heeft gebroken en onder welke

omstandigheden. Het is goed mogelijk dat wij u dit in 2009 ook al gevraagd hebben. Op grond

van de gegevens van 2009 konden we helaas nog niet goed conclusies trekken. We hopen dat

nu, bijna 7 later wel te kunnen. Als u destijds al uw gegevens heeft opgestuurd vragen wij u

de enquête in te vullen vanaf 2009 tot nu. Wij zouden deze extra moeite enorm waarderen.

Samenvattend: wat vragen wij u?

1. Toestemming voor het gebruik van uw gegevens voor onderzoeken naar

mastocytose, zoals hierboven omschreven.

30

2. Toestemming voor het opvragen van uw apothekersgegevens in het kader van het

botontkalkingsonderzoek. Uiteraard worden ook deze gegevens volledig

geanonimiseerd verwerkt en ook dit kost u geen extra bezoeken of onderzoeken.

3. Ten slotte willen wij u vragen of u voor ons een korte enquête m.b.t. eventuele

botbreuken in zou willen vullen.

Wij vragen u vriendelijk om uw toestemming voor de algemene gegevens, de toestemming voor

de apotheekgegevens en de ingevulde enquête over botbreuken op te sturen in bijgaande

antwoordenvelop. U helpt ons en andere mastocytose patiënten enorm mee.

Bij voorbaat hartelijk dank!

Hoogachtend,

Mede namens Dr. J.N.G. (Hanneke) Oude Elberink, internist-allergoloog

Merel Onnes

Student-onderzoeker

31

Bijlage 1 van 3

Toestemmingsformulier voor het gebruik van gegevens voor mastocytose-onderzoek

Met dit formulier geeft u om toestemming om gegevens uit uw medisch dossier beschikbaar te

stellen voor medisch-wetenschappelijk onderzoek naar mastocytose.

Het gaat hierbij om algemene gegevens als leeftijd en geslacht en om uitslagen van medische

testen, zoals labwaarden, röntgenfoto’s en uitslagen van biopten. Alle gegevens zullen te allen

tijde volledig geanonimiseerd gebruikt worden. U behoudt altijd het recht om uw toestemming

weer in te trekken.

Met uw gegevens kunnen wij de kennis over deze relatief zeldzame ziekte vergroten om zo

uiteindelijk tot betere behandelmogelijkheden te komen.

Ik verklaar het bovenstaande begrepen te hebben en geef de onderzoeksgroep mastocytose van

het Universitair Medisch Centrum Groningen toestemming om mijn gegevens te gebruiken

voor medisch-wetenschappelijk onderzoek naar mastocytose.

Naam:

Geboortedatum:

Datum:

Handtekening:

32

Bijlage 2 van 3

Toestemming voor het opvragen van apothekersgegevens voor mastocytose-onderzoek

Met dit formulier geeft u de onderzoekers van de mastocytose werkgroep van het Universitair

Medisch Centrum Groningen toestemming om uw apothekersgegevens op te vragen en te

gebruiken voor medisch wetenschappelijk onderzoek.

Het gaat hierbij om data waarop de medicijnen zijn opgehaald en in welke hoeveelheden dit

gebeurt is. Het betreft de volgende medicatiegroepen: bisfosfonaten, calcium en vitamine D.

Met behulp van deze gegevens willen wij het gebruik van deze medicatie zo goed mogelijk in

beeld brengen. Hierdoor kunnen wij vervolgens de effectiviteit van deze medicatie beter kunnen

evalueren. Wij zullen ons hierbij vooral richten op het effect van deze medicatie op het

voorkomen van fracturen.

Ik verklaar het bovenstaande begrepen te hebben en geef de onderzoeksgroep mastocytose van

het Universitair Medisch Centrum Groningen toestemming om bovengenoemde

apothekersgegevens op te vragen en te gebruiken voor het omschreven onderzoek.

Naam:

Geboortedatum:

Datum:

Handtekening:

33

Bijlage 3 van 3

Enquête over botbreuken

Datum van invullen:

Naam:

Geboortedatum:

Heeft u ooit één of meerdere botten gebroken?

o Ja

o Nee

Zo ja, wilt u dan hieronder aangeven welk(e) bot(ten) u heeft gebroken, wanneer u deze heeft

gebroken en waardoor u deze heeft gebroken?

Voorbeeld:

Welk bot: rechterbovenbeen

Wanneer: maart 1984

Waardoor: val van 3 meter hoog

Welk bot Wanneer (maand + jaartal,

evt. bij benadering)

Waardoor

34

Appendix 3

Letter to pharmacists

Geachte heer/ mevrouw,

Momenteel evalueert de mastocytose-werkgroep van het UMCG de behandeling van

osteoporose bij systemische mastocytose. Daarom ontvang ik graag van u een overzicht van het

gebruik van bisfosfonaten, calcium en vitamine D, m.n. een overzicht van alle afhaaldata en

geleverde hoeveelheden, vanaf de start van de behandeling van deze medicamenten van dhr./

mw. geboren dd-mm-jjjj. De patiënt in kwestie heeft ons schriftelijk toestemming verleent tot

het opvragen van deze gegevens.

Ons faxnummer is 050-3619308. Mocht u vragen hebben dan kunt u ons ook bellen of mailen.

Bij voorbaat hartelijk dank voor uw medewerking,

Hoogachtend,

Merel Onnes

Student-onderzoeker

Mede namens

Dr. J.N.G. (Hanneke) Oude Elberink

Internist-allergoloog

35

Appendix 4

Plots of T scores lumbar BMD subgroups

per protocol

0 1-6

-4

-2

0

2 p=0.004/0.042

moment of measurement

T s

co

re lu

mb

ar

Black: male, red: female Black: not per protocol, red: per protocol

start until 2005 / after 2005

0 1-6

-4

-2

0

2 p=0.002/0.068

moment of measurement

T s

co

re lu

mb

ar

Black: start ≥ 2005, red: start < 2005

lumb#follow-up

0 1-6

-4

-2

0

2 p=0.006/0.025

moment of measurement

T s

co

re lu

mb

ar

lumb# at start of treatment

0 1-6

-4

-2

0

2 p=0.008/0.026

moment of measurement

T s

co

re lu

mb

ar

Black: no fracture, red: fracture Black: no fracture, red: fracture

male female

0 1-6

-4

-2

0

2 p=0.005/0.036

moment of measurement

T s

co

re lu

mb

ar

36

Appendix 5

Baseline variables of subgroups

zCTx

mean

(sd)

P T femur

BMD

median

(IQR)

p BMI

mean

(sd)

P Tryptase

median

(IQR)

P

Men 0.47

(1.56)

0.139 -1.1

(-1.75 to

-0.55)

0.32 26.1

(3.6)

0.464 39.8

(27.2 to

73.4)

0.47

Women 1.54

(1.97)

-1.45

(-2.08 to

-0.55)

25.1

(4.3)

63.7

(21.2 to

124)

Per

protocol

-0.01

(1.19)

0.085 -1.50

(-1.95 to

-0.55)

0.746 25.7

(4.1)

0.930 24.9

(16.8 to

39.1)

0.001

Not per

protocol

1.38

(1.91)

-1.15

(-1.90 to

-0.55)

25.6

(4.1)

70.4

(33.0 to

121.8)

Early start

of

treatment

1.46

(2.69)

0.721 -1.00

(-1.85 to

-0.70)

0.840 23.7

(2.2)

0.081 51.3

(35.6 to

157.5)

0.175

Late start

of

treatment

0.97

(1.81)

-1.35

(-1.90 to

-0.50)

26.4

(4.3)

51.9

(20.0 to

83.5)

Lumbar #

prior to

start of

treatment

0.93

(1.97)

0.835 -1.20

(-1.90 to

-0.63)

0.840 24.5

(3.3)

0.578 51.3

(27.0 to

94.5)

0.643

No lumbar

# prior to

start of

treatment

1.16

(1.56)

-1.40

(-1.95 to

-0.50)

30.2

(3.5)

53.5

(17.8 to

97.2)

Lumbar #

during

follow-up

0.85

(1.10)

0.775 -1.50

(-1.80 to

-1.10)

0.390 26.4

(3.6)

0.000 29.5

(27.2 to

53.5)

0.483

No lumbar

# during

follow-up

1.04

(1.98)

-0.95

(-1.93 to

-0.50)

25.4

(4.1)

52.9

(21.2 to

95.3)

37

Appendix 6

Plot of T and Z score femoral BMD

T score femur: baseline - 5 years

0 1-3

-2

-1

0

1 p=0.081

moment of measurement

T s

co

re f

em

ur

z femur

0 1

-2

0

2

p = 0.019

moment of measurementZ s

co

re f

em

ora

l