Effect of near normoglycemia for 5 years on progression of early diabetic retinopathy and renal involvement

Abstract

The effect of strict metabolic control for 5 years on renal function and retinal morphology was estimated in 24 insulin-dependent diabetic individuals (age 29 +/- 8 years, diabetes duration 10 +/- 6 years) with albustix negative urine and minimal or no background retinopathy before the study. They were randomized to conventional insulin treatment (CIT) or continuous subcutaneous insulin infusion (CSII) with a portable pump. During CSII treatment the metabolic status was significantly improved. HbA1c fell from 8.9 +/- 2.0 to 7.4 +/- 1.3% (p less than 0.01) whereas HbA1c was unchanged during CIT treatment. The mean value of urinary albumin excretion (UAE) was not statistically significantly changed (from 12 +/- 10 mg/24 h to 13 +/- 5 mg/24 h in CSII patients and from 14 +/- 12 to 11 +/- 6 mg/24 h in CIT patients (p greater than 0.1). On the other hand, the elevated GFR values were significantly reduced in both CSII and CIT patients, 129 +/- 17 to 120 +/- 9 and 129 +/- 18 to 119 +/- 12 ml/min.1,73m2, respectively (p less than 0.05). Both the number of microaneurysms, haemorrhages and exudates tended to increase mor in CIT patients than in CSII patients during the 5 year study period, but the differences did not reach statistically significance (p greater than 0.1). Pump treatment did not induce proliferations or "cotton wool" exudates. We conclude that no statistically significantly differences between GFR values, UAE rates, and progression of background retinopathy was observed between normoalbuminuric IDDM patients treated for 5 years with CIT and CSII, respectively. However, due to the size of the material a type II error must be taken into consideration.