PREDICTORS OF THE PROGRESSION OF RENAL-DISEASE IN THE MODIFICATION OFDIET IN RENAL-DISEASE STUDY

The Modification of Diet in Renal Disease (MDRD) Study examined the ef fects of dietary protein restriction and strict blood pressure control on the decline in glomerular filtration rate (GFR) in 840 patients wi th diverse renal diseases. We describe a systematic analysis to determ ine baseline factors that predict the decline in GFR, or which alter t he efficacy of the diet or blood pressure interventions. Univariate an alysis identified 18 of 41 investigated baseline factors as significan t (P < 0.05) predictors of GFR decline. In multivariate analysis, six factors-greater urine protein excretion, diagnosis of polycystic kidne y disease (PKD), lower serum transferrin, higher mean arterial pressur e, black race, and lower serum HDL cholesterol-independently predicted a faster decline in GFR. Together with the study interventions, these six factors accounted for 34.5% and 33.9% of the variance between pat ients in GFR slopes in Studies A and B, respectively, with proteinuria and PKD playing the predominant role. The mean rate of GFR decline wa s not significantly related to baseline GFR, suggesting an approximate ly linear mean GFR decline as renal disease progresses. The 41 baselin e predictors were also assessed for their interactions with the diet a nd blood pressure interventions. A greater benefit of the low blood pr essure intervention was found in patients with higher baseline urine p rotein. None of the 41 baseline factors were shown to predict a greate r or lesser effect of dietary protein restriction.