Death, end-stage renal disease and renal function decline in patients with diabetic nephropathy in French cohorts of type 1 and type 2 diabetes.

AIMS/HYPOTHESIS: Microvascular complications are a common feature of diabetes but additional research is needed regarding diabetic nephropathy endpoints in type 1 and type 2 diabetes.

METHODS

We compared 277 type 1 diabetes patients with 942 type 2 diabetes patients, with clinical proteinuria and no endstage renal disease (ESRD) at baseline, prospectively followed for death, ESRD and decline in estimated glomerular filtration rate (eGFR, all available measures).

RESULTS

The incidence rate of death was 67.0 (95% CI 59.2, 74.8) vs. 24.6 (95% CI, 19.0, 30.2) per 1,000 patient-years, in type 2 diabetes and type 1 diabetes, respectively. Unadjusted risk for death was greater for type 2 diabetes patients (HR 3.423; 95% CI, 2.501, 4.683; p<0.0001), but the difference did not persist after adjustment for age (HRage-adj 0.859; 95% CI 0.581, 1.269; p=0.445). The incidence rate of ESRD was 18.4 (95% CI 14.2, 22.5) vs. 47.1 (95%CI 38.4, 55.9) per 1,000 patient-years, in type 2 diabetes and type 1 diabetes, respectively. Unadjusted risk for ESRD was lower in type 2 diabetes (HR 0.399; 95% CI 0.287, 0.554; p<0.0001), but the difference did not persist after adjustment for sex, age and baseline serum creatinine (HRadj 0.989; 95% CI 0.597, 1.639; p=0.965). In a mixed linear model, eGFR decline was not significantly different in type 2 vs. type 1 diabetes (difference in slope −0.19 [0.28] ml min(−1) 1.73 m(−2) year(−1); p=0.512).

CONCLUSIONS/INTERPRETATION: In diabetic nephropathy, once baseline risk factors were taken into account the risk for death, ESRD and renal function decline did not significantly differ between type 1 diabetes and type 2 diabetes.