NDT Advance Access originally published online on September 22, 2007
Nephrology Dialysis Transplantation 2008 23(1):422-423; doi:10.1093/ndt/gfm578
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Influence of residual diuresis on insulin requirement in insulin-treated type 2 diabetic patients during the first year of haemodialysis
Email: georg.biesenbach{at}akh.linz.at
Sir,
In insulin-treated diabetic patients with renal failure, the insulin requirement decreases in a linear correlation to the fall in glomerular filtration rate (GFR). The lower need of insulin doses in renal insufficiency can mostly be explained by a lower renal excretion rate of insulin, due to a prolongation of the half-life of circulating insulin [1]. Insulin resistance in uraemic diabetic patients can be improved by dialysis; however, insulin resistance remains elevated in insulin-treated diabetic patients after the start of haemodialysis [2]. In our study, we evaluated the insulin requirement during the first dialysis year in insulin-treated type 2 diabetic patients.
A total of 24 insulin-treated type 2 diabetic patients [age 62 ± 9 years, female/male (9 : 15)], who had been at least 1 year on haemodialyis therapy, were selected for this study.
Patients were divided into two groups according to their diuresis: a group 1, of patients with preserved near-normal urine production (>1 l/day) during the first dialysis year (n = 12), and a group 2, of patients with significant reduction of urine excretion (<0.5 l/day) within 3 months after start of dialysis (n = 12). All patients were dialysed three times per week (total dialysis time 12 h weekly). The HbA1c- and FBG-values as well as the BP-values were similarly high in both groups and did not significantly change during the 1-year observation period. In group 1, the Cr-Cl dropped from 11 ± 4 ml/in at the start of dialysis to 6 ± 2 ml/min after 1 year. In group 2, the Cr-Cl decreased from 10 ± 4 ml/min to 1 ± 1 ml/min during the same time. The insulin requirement in the patients with normal diuresis decreased from 24 ± 8 IU/day at the start of dialysis to 14 ± 8 IU/day 1 year later (41% reduction, P < 0.05). In the group with reduced diuresis, the required insulin dose remained the same with 28 ± 12 and 26 ± 8 IU/day, respectively (7% reduction). The kidney plays a pivotal role in the clearance and degradation of circulating insulin and is also an important site of insulin action [3]. In the presence of impaired renal function, insulin clearance is prolonged [1], and therefore, insulin requirement is decreased, though insulin resistance frequently accompanies end-stage renal disease.
We agree that the conclusions in our study are limited due to the small patient groups. The C-peptide levels were not significantly different in both groups, therefore, residual β-cell function obviously had no impact on the insulin requirement under haemodialysis. In a study with type 1 diabetic patients with moderate renal insufficiency, it was reported that their insulin levels were higher than in diabetic patients with normal renal function [4].
Thus, according to the results in our study, it can be concluded that also under dialysis, residual renal function (GFR) has an impact on insulin requirement. In insulin-treated type 2 diabetic patients, early reduction of diuresis significantly decreases insulin requirement.
Conflict of interest statement. None declared.
From the 2nd Department of
Medicine, Section Nephrology
General Hospital Linz, Austria
Notes
See http://www.oxfordjournals.org/our_journals/ndtplus/
References
- Biesenbach G, Raml A, Scmekal B, Eichbauer-Sturm G. Decreased insulin requirement in relation to GFR in nephropathic Type 1 and insulin-treated Type 2 diabetic patients. Diabet Med (2003) 20:642–645.[CrossRef][Web of Science][Medline]
- Rabkin R, Ryan MP, Duckworth WG. The renal metabolism of insulin. Diabetologia (1984) 27:351–357.[CrossRef][Web of Science][Medline]
- Sensson M, Yu ZW, Eriksson JW. A small reduction in glomerular filtration is accompanied by insulin resistance in type I diabetes patients with diabetic nephrophathy. Eur J Clin Invest (2002) 32:100–109.[CrossRef][Web of Science][Medline]
- Rave K, Heise T, Prützner A, Heinemann L, Sawicki PT. Impact of diabetic nephropathyon pharmaacodynamic and pharmacokinetic properties of insulin in type 1 diabetic patients. Diabetes Care (2001) 24:886–896.
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