Glomerular filtration rate in Indian non-insulin-dependent diabetics at various stages of albuminuria.

Sixty-seven non-insulin-dependent diabetic subjects were selected to estimate the glomerular filtration rate (GFR). All patients had satisfactory glycaemic control (HbA1 < 9.5%). GFR was determined using Technetium 99m DTPA by the method devised by Gates. Thirty-eight subjects had normal albumin excretion (UAE < 20 micrograms/min), 15 had UAE in the microalbuminuric range (20-100 micrograms/min), and the rest were macroalbuminuric (> 200 micrograms/min). GFR was lower in the normoalbuminuric patients as compared to the controls, but the decrease was not significant (71.5 (21.4) vs. 98.3 (16.1) ml/min per 1.73 m2. GFR was significantly decreased in both micro and macroalbuminuric groups (64.0 (24.5) and 53.8 (27.3) ml/min per 1.73 m2, respectively) (P < 0.05). No appreciable change in GFR was observed in normoalbuminuric patients with increasing duration of diabetes, however, there was a steady decline in GFR with time in both micro- and macroalbuminuric patients. Hypertension was present in 79%, 47% and 16% of macro-, micro- and normoalbuminuric patients, respectively. GFR was significantly lower in hypertensive diabetic patients compared to normotensives (52.3 vs. 76.1 ml/min per 1.73 m2) (P < 0.01), while this difference was not significant in the micro- and macroalbuminuric groups. We conclude from our study that the stage of hyperfiltration could not be detected in non-insulin-dependent diabetes and that hypertension has a significant influence on the rate of decline of GFR.