Effect of continuous subcutaneous insulin infusion on kidney function and size in IDDM patients: a 2 year controlled study

Abstract

Glomerular filtration rate (GFR), renal plasma flow (RPF), kidney volume, and urinary albumin excretion rate were measured in 24 insulin-dependent diabetics, aged 29 +/- 7 years (mean +/- SD) with diabetes duration of 8 +/- 4 years who were randomly allocated to either continuous subcutaneous insulin infusion (CSII) (n = 12) or unchanged conventional insulin treatment (CIT) (n = 12). GFR, RPF, and kidney volume were identical but significantly increased above normal values in the two groups at the start of the study. After 24 months of CSII treatment, significant reduction in GFR was seen compared to pretreatment values (145 +/- 21 ml/min vs 139 +/- 21 ml/min, 2p less than 5.0%). However, RPF was not reduced after 24 months of CSII treatment (608 +/- 104 ml/min vs 601 +/- 106 ml/min). In the CIT group no changes in GFR or RPF was seen, and kidney volume remained unchanged in both groups; urinary albumin excretion was normal or near normal in both groups and remained unchanged. Thus, improved glycemic control in long-term IDDM patients is associated with normalization (reduction) of renal "hyperfunction," but despite this, no reduction was seen in the associated nephromegaly.