PREDICTORS OF PROGRESSION OF DIABETIC NEPHROPATHY - IMPLICATION FOR TIMING OF KIDNEY-TRANSPLANTATION

Multiple risk factors are important predictors in the development of d iabetic nephropathy (DN). Once DN has developed, it progresses steadil y to renal failure. To determine the rate of renal function decline an d the parameters that influence the rate of decline, we retrospectivel y reviewed the charts of patients with DN who had undergone dialysis o r kidney transplantation at the Mayo Clinic from 1983 to 1993. Forty p atients were found to have two or more iothalamate clearance (IothmCl) measurements where a slope of renal function decline over time, expre ssed as mL/min/month/1.73 m(2), can be calculated. The parameters exam ined included age of onset and duration of diabetes (DM), age at initi al presentation, insulin dosage, glycosylated hemoglobin level, protei nuria, blood pressure (BP), number of antihypertensive medications (HT M), use of ACE inhibitors, creatinine, and initial IothmCl, The mean o verall decline of clearance was 1.36+/-1.1 mL/min/month, corrected. Un ivariate regression analysis showed that only systolic and mean BP (p< 0.05), use of HTM (p=0.02), and the number of HTM used (p=0.0001) corr elated with the rate of clearance decline. No other parameter was sign ificant. The decline of IothmCl was 0.72+/-0.41, 1.20+/-0.9, and 2.34/-1.38 mL/min/month, for patients taking no HTM, <3 HTM, and greater t han or equal to 3HTM, respectively. Of the eight patients on HTM who p resented with initial IothmCl of <30 mL/min/1.73 m(2), seven (88%) had clearance of <10 mL/min/1.73 m(2) within 1 yr. We conclude that hyper tension is an important marker of DN progression, and that the more HT M required for control of BP, the faster the decline of renal function , We recommend that a suitable transplant candidate with DN who presen ts with hypertension requiring HTM and a clearance of <30 mL/min shoul d be placed on the transplant waiting list.