The impact of co-morbid risk factors at the start of dialysis upon the survival of ESRD patients.

By using a computerized database, we have catalogued the presence of 29 co-morbid risk factors in 683 patients with end-stage renal disease who started dialysis from 1970 through 1989, with follow-up through 1992. The authors hypothesized that current end-stage renal disease patients have more serious co-morbid risk factors impacting upon their mortality rate. Quantitation of dialysis patient co-morbidity, as a measure of patient illness, is lacking in the general nephrology literature. Seven co-morbid risk factors have been reserved for new dialysis patients: hypertension, low albumin, cerebral vascular disease, peripheral vascular disease, pre-existing cardiac disease, abnormal EKG/old myocardial infarction, and congestive heart failure. Except for low serum albumin, the proportion of patients with the six other co-morbid risk factors has increased significantly over this 20-year period (p < 0.0001, chi-square test for hypertension, peripheral vascular disease, pre-existing cardiac disease, abnormal EKG/old myocardial infarction, and congestive heart failure, and p < 0.006 for cerebral vascular disease). In addition, the co-morbid risk factors of hypertension, low serum albumin, and pre-existing cardiac disease at the start of dialysis were strongly prognostic of survival. The Cox proportional hazards regression model identified these three risks, among other factors, that were significantly associated with a decreased survival, with risk ratios ranging from 1.40-1.66. These results support the authors' hypothesis that incoming end-stage renal disease patients, who recently start dialysis, are sicker than in the earlier years of the authors' program. If the authors' patients reflect the national end-stage renal disease population, the presence of co-morbid risk factors may, in part, explain the continuing high mortality of dialysis patients.