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Introduction

Anaemia is common in diabetes. Causes of anaemia includeadvanced diabetic nephropathy, iron deficiency, chronicinflammatory diseases, malignancy or chronic infection [1,2].We also encounter diabetic patients with anaemia of unknowncause, despite routine haematological studies [3–7]. We havepreviously reported that reduced erythropoietin (Epo) respon-

siveness to anaemia may explain atypical anaemia before thedevelopment of advanced diabetic nephropathy [8].

Recombinant human erythropoietin (rHuEpo) can enhanceerythropoiesis in bone marrow in a dose-dependent manner[9,10] and is generally used to treat anaemia in chronic renalfailure. It has also been given in anaemia due to zidovudinetherapy in acquired immunodeficiency syndrome (AIDS) [11],cancer chemotherapy [12] and early diabetic nephropathy[3–6].

The aim of this study was to investigate both the therapeuticeffects of rHuEpo on anaemia with erythropoietin deficiencyin diabetic patients, and characteristics predicting the thera-peutic effect.

Correspondence to

: Hyun Chul Lee, Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.

Abstract

Aims

The aim of this study was to investigate the therapeutic effect of recom-binant human erythropoietin (rHuEpo) on anaemia with erythropoietin defi-ciency in diabetic patients.

Methods

Twenty diabetic patients with anaemia and Epo deficiency were en-rolled. All patients were treated with rHuEpo (Epokine®; 4000 U/day s.c., threetimes a week) for 8 weeks.

Results

The responder group (

n

= 14) had significant increments in haemo-globin compared with the non-responder group (

n

= 6) (

P

< 0.05). No signifi-cant differences were found between the responder and non-responder groupsin terms of duration of diabetes mellitus, serum creatinine level, 24-h urine albu-min excretion rates, frequency of diabetic microangiopathy, or HbA

1c

. Therewas no difference between the two groups in terms of serum iron and total iron-binding capacity (TIBC). Serum ferritin level was significantly higher in the re-sponder group than in the non-responder group (240.3

±

108.4, 25.8

±

3.0

µ

g / l,

P

< 0.05), as was transferrin saturation (32.7

±

7.9%, 21.2

±

5.3%,

P

< 0.05).

Conclusions

rHuEpo could be useful in the treatment of anaemia with erythro-poietin deficiency in diabetic patients, and the degree of iron storage and functionaliron deficiency might be the main cause of hyporesponsiveness to rHuEpo.

Diabet. Med. 20, 661–664 (2003)

Keywords

anaemia, erythropoietin, diabetic nephropathy, recombinanterythropoietin

Blackwell Publishing Ltd.Oxford, UKDMEDiabetic Medicine0742-3071Blackwell Science Ltd, 200320Original ArticleOriginal articleTherapeutic effect of rHuEpo on anaemia D. J. Kim et al.

Therapeutic effect of recombinant human erythropoietin on anaemia with erythropoietin deficiency in diabetic patients

D. J. Kim, Y. M. Kim*, Y. S. Yun*, C. W. Ahn*, B. S. Cha*, Y. D. Song, S. K. Lim*, K. R. Kim*, J. S. Hahn†, K. B. Huh* and H. C. Lee*

Department of Internal Medicine, National Health Insurance Corporation Ilsan Hospital, Koyang, and *Divisions of Endocrinology and Metabolism and †Haematology and Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea

Accepted 28 February 2003

© 2003 Diabetes UK.

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Therapeutic effect of rHuEpo on anaemia •

D. J. Kim et al.

Patients and methods

Patients

Patients were recruited from the Severance Hospital DiabetesCentre. The study was approved by the ethics committee ofthe Severance Hospital, and all patients gave informed consent.All subjects were diabetic patients with anaemia and Epo defi-ciency, defined as a haemoglobin level < 11.0 g/dl for womenand 12.0 g/dl for men.

Patients with a serum creatinine of < 133

µ

mol/ l (1.5 mg/dl)were selected to exclude advanced diabetic nephropathy. Weexcluded those with secondary causes of anaemia, includingthose with liver disease, malignant disorders, renal disease,haemorrhage, tuberculosis, rheumatoid arthritis, systemiclupus nephritis, and AIDS. In addition, those with iron, vitaminB12, or folic acid deficiency, or those receiving iron supple-ments were also excluded. Iron deficiency anaemia was definedas a serum iron concentration of < 5.4

µ

mol/ l (30

µ

g /dl) and aserum ferritin concentration of < 15

µ

g / l.

Methods

We recruited 20 diabetic patients with anaemia and Epo defi-ciency. At baseline, patients were evaluated by history andphysical examination, blood count, and serum chemistry includ-ing iron studies.

Serum Epo was measured by the

125

I radioimmunoassaymethod using DPO-Trac

TM

(DiaSorin Inc, Stillwater, MN,USA). The normal range of serum Epo in our laboratory was9.1–30.8 U/l.

All patients were treated with rHuEpo (Epokine®; CJ Co.,Korea) 4000 U/day s.c., three times a week) for 8 weeks.Patients were monitored by blood count every 2 weeks. Afterreaching target haemoglobin level 13.0 g/dl for women and14.0 g/dl for men, rHuEpo was discontinued. Patients withincrements in haemoglobin level of > 2.0 g/dl, or a final haemo-globin > 13.0 g/dl for women and 14.0 g/dl for men were de-fined as responders.

Statistical analysis

Statistical analyses were performed using SPSS (Window re-lease 10.0). All values are given as mean

±

SD

, or number. Theresponsiveness to rHuEpo and comparison of clinical and bio-chemical variables between the responder and non-respondergroups were analysed by Student’s

t

-test, and

χ

2

test. Statisticalsignificance was set at

P

< 0.05.

Results

The clinical and biochemical characteristics of the subjects areshown in Table 1. Serum Epo concentrations ranged from10.6 to 22.4 U/l.

There was no difference between the responder (

n

= 14) andnon-responder (

n

= 6) groups in terms of the pretreatmenthaemoglobin (10.0

±

0.8, 9.4

±

1.2 g/dl,

P

= 0.170, Fig. 1). Thehaemoglobin of responders was significantly increased as early

as 2 weeks after starting rHuEpo (

P

< 0.001), and was signifi-cantly higher than non-responders (

P

< 0.05). The meanduration of rHuEpo administration of responders was 4.9

±

2.3 weeks (2–8 weeks). The weekly change of haemoglobin(

∆

Hb/week) of both groups was 0.83

±

0.39, 0.13

±

0.14 g/dlper week (

P

< 0.001).No significant differences were found between responders

and non-responders in terms of duration of diabetes mellitus,serum creatinine level, 24-h urine albumin excretion, diabeticmicroangiopathy, or HbA

1c

(Table 2). The mean corpuscularvolume (MCV) prior to treatment tended to be lower in non-responders (

P

= 0.09), and no difference in mean corpuscularhaemoglobin (MCH) was found between the two groups(

P

= 0.12). Moreover, no difference was observed between thetwo groups in terms of the serum Epo prior to treatment(13.2

±

2.0, 14.6

±

4.6 U/l,

P

= 0.947).Figure 2 shows the iron profiles of responders and non-

responders. There was no difference between the groups interms of serum iron (9.4

±

4.0, 7.6

±

5.4

µ

mol/ l,

P

= 0.560)and total iron-binding capacity (TIBC) (38.0

±

9.3, 44.0

±

23.2

µ

mol/ l,

P

= 0.507). Serum ferritin was higher in respond-ers than in non-responders (240

±

108 vs. 25.8

±

3.0

µ

g / l,

P

< 0.05), as was transferrin saturation (32.7

±

7.9% vs.21.2

±

5.3%,

P

< 0.05).

Table 1 Clinical and biochemical characteristics of study subjects

N 20Sex (M : F) 8 : 12Age (years) 53 ± 9Duration of diabetes (years) 13 ± 5Retinopathy (n) 18Nephropathy (n) 19Neuropathy (n) 18Serum creatinine (µmol/ l) 106 ± 1824-h urine albumin excretion rates (mg/day) 3254 ± 2608Fasting blood glucose (mmol/ l) 8.7 ± 3.1HbA1c (%) 8.9 ± 2.3Serum Epo concentration (U/l) 13.6 ± 2.7

Data are numbers or means ± SD.

Figure 1 Comparison of haemoglobin level between responders (�) and non-responders (�). *P < 0.05; **P < 0.01.

Original article

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Two patients in the non-responder group increasedtheir haemoglobin after oral iron supplementation duringrHuEpo treatment (from 8.1 and 7.9 to 11.4 and 12.7 g/dl,respectively).

We observed no serious side-effects or complications, suchas worsening of hypertension, renal failure or convulsion. Allpatients were symptomatically improved.

Discussion

We have shown that rHuEpo treatment successfully correctedanaemia with Epo deficiency in diabetic patients and that ironstatus modulates its therapeutic effects.

Anaemia with Epo deficiency is not normally observeduntil advanced renal failure, with glomerular filtration rates

Responder Non-responder P

n 14 6 —Duration of diabetes (years) 11 ± 5 16 ± 5 0.10624-h urine albumin excretion rates (mg/day) 3470 ± 2948 2750 ± 1673 0.586Serum creatinine (µmol/ l) 106 ± 18 115 ± 18 0.709Retinopathy (n) 12 6 1.000Nephropathy (n) 13 6 1.000Neuropathy (n) 13 5 0.521Pretreatment HbA1c (%) 8.6 ± 2.1 9.3 ± 2.9 0.556Post-treatment HbA1c (%) 8.0 ± 2.2 7.9 ± 1.4 0.865Mean corpuscular volume (fl) 91.7 ± 5.7 87.2 ± 3.5 0.090Mean corpuscular haemoglobin (pg) 31.2 ± 2.5 29.9 ± 1.1 0.119Serum Epo concentration (U/l) 13.2 ± 2.0 14.6 ± 4.6 0.947

Data are numbers or means ± SD.

Table 2 Clinical and biochemical characteristics of the responder and non-responder groups

Figure 2 Profiles of iron stores in responders and non-responders. TIBC, Total iron-binding capacity. *P < 0.05.

© 2003 Diabetes UK.

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Therapeutic effect of rHuEpo on anaemia •

D. J. Kim et al.

< 40 ml/min, equivalent to serum creatinines > 10

µ

mol/ l[13]. The patients in this study had normal renal function, butheavy proteinuria with mean 24-h urine albumin excretionrates of > 3 g/day. Moreover, serum Epo concentrations werewithin the normal range, and lower than those of non-diabeticsubjects with anaemia. Perhaps excessive loss of Epo in theurine results in anaemia with Epo deficiency in these patients.

Functional iron deficiency, defined as inadequate iron sup-ply to the bone marrow in spite of normal body iron stores,may develop during rHuEpo treatment, leading to a dimin-ished response [14]. In the present study, the non-respondersshowed significantly lower concentrations of serum ferritinand transferrin saturation than responders. Thus, the responseto rHuEpo was mainly related to iron status. Cazzola

et al

.[14] recommended that oral iron supplementation is adminis-tered during at least the first week of rHuEpo treatment. Moreintensive iron supplementation is recommended when trans-ferrin saturation is lower than 20% and/or serum ferritin levelis lower than 100

µ

g / l.The optimum initial dose of rHuEpo is not agreed in early

diabetic nephropathy. In this study, the dosage of rHuEpo wasabout 180 U/kg per week, similar to the initial dose (200–250 U/kg per week) recommended by Cazzola

et al

. [14]. Webelieve that diabetes is frequently associated with chronicinflammation and decreased Epo responsiveness, and feel thata higher rHuEpo dose gives a better and stronger response.However, Winkler et al. [5] reported adequate responses at dosesas low as 75 U/kg per week. Further studies are clearly needed.

In this study, the responder group reached target haemo-globin after 5 weeks (2–8 weeks) of treatment, with meanchanges of haemoglobin levels of about 0.5–1.0 g/dl per week.This suggests that the response to rHuEpo may be recognizedby a rise in haemoglobin after 2–4 weeks’ treatment of > 1.0 g/dl.

There were several limitations to our study. First, we did notformally assess quality of life. Second, we did not include oraliron supplementation, and this may explain the poor responseto rHuEpo. Third, we did not assess subclinical inflammation,another possible cause of a poor response.

In conclusion, rHuEpo may be useful in the treatment ofanaemia with erythropoietin deficiency in diabetic patients, andthe degree of iron storage and functional iron deficiency appearsto be the main cause of hyporesponsiveness to treatment.

Acknowledgements

We thank CJ Co., who provided recombinant human erythro-poietin (Epokine®). This study was supported by Brain Korea

21 Project for Medical Sciences, and by a grant from theNational R&D programme, Ministry of Science Technology,Republic of Korea (M10104000170-02J0000-07310). Thisstudy was presented at the 61st Annual Meeting of the Amer-ican Diabetes Association, Philadelphia, PA, 2001.

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