ESPACOMP 2013 Measurement and determinants of the 3 elements of patient adherence to

medications: initiation, implementation and discontinuation

Adherence to phosphate binders in

haemodialysis patients: prevalence and

determinants

15 November 2013

Yoleen PM Van Camp, Bernard Vrijens, Ivo Abraham,

Bart Van Rompaey and Monique M Elseviers

1

Influence of adherence on mortality

(Simpson et al., 2006 (BMJ))

2

INTRODUCTION – PhD study

Map extent of nonadherence + determinants Chronic dialysis: phosphate binders

Diabetes type 2

Chronic heart failure

Improve adherence (nurse-led)

Question 1 Question 2

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INTRODUCTION – phosphate cycle Phosphate binders in dialysis patients

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Phosphate binders in dialysis patients

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METHODOLOGY – study design

135 chronic dialysis patients

2 months passive adherence measure

Baseline questionnaires Demographical Medical and pharmacological Social support Knowledge Health beliefs Side effects Depression Quality of life (SF-36)

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METHODOLOGY – adherence measure

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METHODOLOGY – adherence measure

Vrijens et al. BJCP 2011

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RESULTS

Study population

Typical dialysis population

- Mean 67 years, 64% male, 70% retired

- 20% side-effects and 20% inconveniences

- Mean oral daily pill burden 12

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Intermezzo 1

Self-report vs electronic adherence measure

10

Self-reported adherence vs electronic measure

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Question 1

The extent of nonadherence

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RESULTS

Extent of nonadherence

How to?

13

Definitions of adherence

Be aware of “false friends”

14

Mean percentage of adherence

vs the proportion of adherent patients

Mr. Red: 6/10 = 60%

Ms. Yellow: 10/10 = 100%

Mr. Blue: 8/10 = 80%

Ms. Green: 10/10 = 100%

Ms. Beige: 4/10 = 40%

Mean % of adherence = % of prescribed doses taken

Proportion of adherent patients (cut-off e.g. ≥80%)

3 in 5 patients = 60%

Mean % of adherence

= 60+100+80+100+40 / 5 = 76%

15

The proportion of adherent patients

Finding a meaningful cut-off

80% = missing a weekly dose of “1,4”

little clinical relevance

<1 total daily dose / week = adherent

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RESULTS

Extent of nonadherence? 78% prescribed doses taken

1 in 2 patients misses ≥1x/week

17

Mean percentage of adherence

vs the proportion of adherent patients

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Intermezzo 2

Consequences of nonadherence

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Mean phosphatemia in adherent

vs nonadherent patients

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Question 2

Determinants of adherence

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RESULTS

Adherence determinants? + Partner and social support (intercorrelated)

+ Physical quality of life (SF-36)

– Intake inconveniences (taste, size, …)

social support + physicial quality of life

= 26% of variance in being adherent

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CONCLUSIONS

Adherence poor Clear definition (% vs proportion)

Meaningful cut-off

Adherence determinants Social support + physical QoL

Need for improvement Social support

Individualised support

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Questions?

• Journal of Nephrology 2013/14 – Van Camp et al. “Adherence to

phosphate binders in hemodialysis patients: prevalence and

determinants” (accepted, soon to be published)

• European Journal of Clinical Pharmacology 2013 – Van Camp et al.

“Nurse-led interventions to enhance adherence to chronic

medication: systematic review and meta-analysis of randomised

controlled trials.” (discussion addresses nonadherence cut-off)

• Journal of Clinical Nursing 2012 – Van Camp et al. “Nurse-led

education and counselling to enhance adherence to phosphate

binders.” (methodology section addresses bias induced by

electronic monitoring)

• CONTACT yoleen.vancamp@uantwerpen.be or yoleen@gmail.com