Higher Hemoglobin Levels in Diabetic Subjects With Renal Hyperfiltration
Article Outline
To the Editor:
Thomas et al recently reported that the decline in hemoglobin (Hb) level began early in the course of diabetic kidney disease in type 2 diabetic patients.1 Glomerular hyperfiltration is the earliest detectable abnormality in diabetic kidney disease;2 however, Thomas et al did not observe a reduction of Hb during the follow-up of subjects with a baseli ne estimated glomerular filtration rate (GFR) >120 mL/min/1.73 m2 (>2.00 mL/s/1.73 m2). The Modification of Diet in Renal Disease (MDRD) estimation is not accurate at high levels of GFR.3, 4 We measured GFR (51Cr-EDTA) and Hb in 63 diabetic patients. For patients aged >40 years, GFR (mL/min/1.73 m2) was age adjusted by first summing GFR and age (in years), and then subtracting 40 (this correction accounts for the natural decline of GFR with age as proposed by Premaratne et al).5 Hb levels were lower in patients without hyperfiltration. We suggest that the decline in hemoglobin in diabetic kidney disease may begin during the transition from hyperfiltration to normal GFR. Table 1.
Table 1. Characteristics of Diabetic Subjects With and Without Hyperfiltration
| Age-adjusted GFR (mL/min/1.73 m2) | P | ||
|---|---|---|---|
| >130 | 90-130 | ||
| n | 14 | 49 | |
| Age-adjusted GFR (mL/min/1.73 m2) | 156 ±20 | 105±10 | <0.001 |
| Serum creatinine (μmol/L) | 79±10 | 92±18 | <0.01 |
| Albumin excretion rate (mg/24 h) | 339±495 | 207±363 | NS |
| Age (y) | 55±16 | 61±14 | NS |
| Diabetes duration (y) | 8±6 | 17±10 | <0.005 |
| Gender | 3F, 11M | 20F, 29M | NS |
| Diabetes type | 11 type 2 | 33 type 2 | NS |
| BMI (kg/m2) | 27.6±4.9 | 27.3±3.8 | NS |
| HbA1c (%) | 9.8±1.3 | 9.2±1.6 | NS |
| Hb (g/dL) | 14.3±1.3 | 13.4±1.4 | <0.05 |
| Red cell volume (fL) | 88±4 | 87±4 | NS |
| C reactive protein (mg/L) | 5.1±2.7 | 7.6±8.4 | NS |
| Subjects treated by ACE inhibitors | 6 | 24 | NS |
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References
- . The epidemiology of hemoglobin levels in patients with type 2 diabetes. Am J Kidney Dis. 2006;48:537–545
- . Early glomerular filtration in insulin-dependent diabetes and late nephropathy. Scand J Clin Lab Invest. 1986;46:201–206
- Estimation of glomerular filtration rate in diabetic subjects, Cockcroft or MDRD formula?. Diabetes Care. 2005;28:838–843
- Are prediction equations for glomerular filtration rate useful for the long-term monitoring of type 2 diabetic patients?. Nephrol Dial Transplant. 2006;21:2152–2158
- . Renal hyperfiltration in type 2 diabetes: effect of age-related decline in glomerular filtration rate. Diabetologia. 2005;48:2486–2493
Editor Note: The corresponding author did not reply.
PII: S0272-6386(06)01910-X
doi:10.1053/j.ajkd.2006.11.047
© 2007 National Kidney Foundation, Inc. Published by Elsevier Inc All rights reserved.
Refers to article:
- The Epidemiology of Hemoglobin Levels in Patients With Type 2 Diabetes , 29 August 2006
