The Modification of Diet in Renal Disease (MDRD) Study was a randomized clinical trial, funded by NIDDK, to determine the effect of dietary protein restriction and strict blood pressure control on the progression of chronic renal diseases of diverse causes in 840 patients. The planned duration of follow-up was 2-4 years, hence, the rate of decline in glomerular filtration rate (GFR), rather than the incidence of renal failure or death, was the primary outcome. The full-scale trial ended patient follow-up in January 1993. The purpose of this proposal is for the Data Coordinating Center (DCC) to obtain long-term followup data on the study Cohort and to continue data analysis. The full-scale trial showed a beneficial effect of the low blood pressure goal in patients with proteinuria and suggested a beneficial effect of reduced protein intake in patients with advanced renal disease (baseline GFR 13-24 mL/min/1.73 m2). However, the length of follow-up was insufficient to determine the efficacy of the low protein diet in patients with moderate renal disease (baseline GFR 25-55 ml/min/1.73m2, N = 585). During 10 months of additional follow-up after the end of the full-scale trial, the number of patients in the GFR 25-55 group to reach renal failure increased from 31 to 55, and a trend suggesting a benefit of the low protein diet on renal failure or death emerged (relative risk 0.63, 95% confidence interval: 0.30 - 1.02, p=.056). Based on observed rates of GFR decline, the projected number of patients in this group to reach renal failure increases to 163 by 9/96 and 263 by 9/2000, providing a unique opportunity for a much more accurate evaluation of this outcome. The primary goals of further follow-up are to assess the long-term effects of the diet and blood pressure interventions on 1) the incidence of renal failure or death and 2) nutritional status and cardiovascular outcomes prior to and following renal failure. Another fundamental goal is to document the long-term progression of renal disease by relating the extensive data from the full-scale study to long-term patient outcomes from the extended follow-up phase. Patient outcomes would be assessed from data provided by the patient and family, physicians' offices, hospital discharge summaries, and the USRDS. A pilot study demonstrating the feasibility of obtaining follow.up information has been completed. The MDRD Study Group has reported many results from the MDRD Study. This proposal will maintain this activity.