Predicting Survival in Adults with End-Stage Renal Disease: An Age Equivalence Index

Abstract

To quantify prognosis in patients with end-stage renal disease, pretreatment clinical state was evaluated and the outcome of all 220 patients who began therapy at 2 hospitals from 1970-1975 was ascertained. Each of 3 pretreatment characteristics made a statistically significant independent contribution to the relative risk of death: age (relative risk for 10 yr increments = 2.0, P < 0.001); duration of diabetes (relative risk for 10 yr increments = 2.0, P < 0.001); and left-sided heart failure (relative risk = 2.0, P < 0.001). The effects of these factors were combined in an age-equivalence index that showed a strong gradient in survival rates from lower to higher values; the 5 yr survival rate differed between 92% in patients with a score of .ltoreq. 30 and 6% in patients with a score > 70. This index, which is simple to use, should prove helpful in patient care and can improve the scientific validity of therapeutic comparisons in patients with end-stage renal disease by identifying and adjusting for the selection biases that occur in the allocation of different treatments.