PREDICTORS OF THE PROGRESSION OF RENAL-INSUFFICIENCY IN PATIENTS WITHINSULIN-DEPENDENT DIABETES AND OVERT DIABETIC NEPHROPATHY

We designed a prospective, double-blind controlled trial to determine predictors of loss of renal function in patients with insulin dependen t diabetes and established nephropathy. A total of 409 insulin-depende nt diabetic patients with established nephropathy enrolled in a trial on the effect of Captopril on the rate of progression of renal disease . Baseline demographic, clinical (history and physical) and laboratory parameters were analyzed as risk factors for time to progression. Dic hotomous characteristics were compared by Fisher's exact test and cont inuous characteristics with the Wilcoxon rank-sum test. Univariate pro portional hazards regression analysis was used to estimate relative ri sk of nephropathy progression, and bivariate proportional hazard regre ssion to identify interactions with the treatment group assignment. Mu ltivariate proportional hazard regression was employed to determine wh ich characteristics were independent risk factors. We found that a num ber of demographic and clinical characteristics were significantly ass ociated with nephropathy progression even after adjustment for treatme nt group. However, after multivariate analysis, the risk factors that independently predicted progression were onset of IDDM later in life, parental diagnosis of IDDM, the presence of edema, increased mean arte rial pressure, and an abnormal electrocardiogram. Likewise, a number o f laboratory characteristics were also predictive of nephropathy progr ession. A low hematocrit, high blood sugar, and higher protein excreti on predicted nephropathy progression as did a higher serum creatinine, particularly in the face of a normal serum albumin. In conclusion, th is study identifies a number of clinical and laboratory risk factors t hat can predict which patients with insulin-dependent diabetes with es tablished nephropathy are more likely to sustain a clinically importan t decrease in renal function over a median follow-up of three years.