Renal disease in diabetics--which patients have diabetic nephropathy and what is their outcome?

From August 1974 to January 1985, 53 patients (26 men; seven Maoris) mean age 45 (SD 15) years, with diabetes mellitus for a mean of 12 (SD nine) years had a renal biopsy and were followed. Indications for biopsy were nephrotic syndrome, proteinuria, renal impairment (five) and hematuria (one). Mean plasma creatinine concentration was 0.22 (SD 0.18) mmol/L and protein excretion 3.4 (SD 2.5) g/24 h. Diabetic nephropathy was demonstrated in 39 patients and significantly associated with retinopathy and insulin dependent diabetes mellitus (IDDM). Of the 39 patients followed for 25.7 (SD 22.8) months, 18 had died (nine myocardial infarction, six uremia, two sepsis, one stroke) and nine had begun dialysis. The five-year cumulative renal survival was 28%. The presence of the nephrotic syndrome and the plasma creatinine concentration at presentation were the best predictors of survival. Diabetics with IDDM of 20 years duration, retinopathy and heavy proteinuria, who survive the other complications of their disease, are likely to have diabetic nephropathy requiring renal replacement therapy.