Baseline variables associated with early death and extended survival on dialysis

Abstract

Patients who die during the first three months on dialysis are not systematically included in the American and European statistics. In contrast, only a few patients survive more than 10 years on this modality of renal replacement therapy. The factors determining these two extreme forms of outcome are poorly understood. We tested the hypothesis that a few variables, easily obtainable at the initiation of dialysis, would identify those individuals at high and low risk of early death. We retrospectively studied 23 patients who died within 90 days of initiating dialysis and 20 patients who survived more than 10 years. These patients were admitted for dialysis to a Brazilian center between July 1, 1976 and February 28, 1997. The baseline variables assessed which were thought to influence survival, were: age, sex, race, body weight, etiology of renal disease, blood pressure, comorbid conditions, hematocrit and serum electrolytes, albumin, creatinine, urea, and urea/creatinine ratio. Univariate analysis showed that patients who died early were older (56.2 ± 15.6 vs. 42.1 ± 10.4 years, p < 0.01), had lower serum creatinine (10.6 ± 2.9 vs. 13.7 ± 3.7 mg/dL, p < 0.01) and albumin (3.3 ± 0.9 vs. 4.0 ± 0.5 g/dL) and a higher urea/creatinine ratio (18.4 ± 5.8 vs. 13.5 ± 4.8, p < 0.01) compared with subjects surviving more than 10 years. Early death patients also had more cases of diabetes (35% vs. 0%, p < 0.01) and less chronic glomerulonephritis (9% vs. 35%, p < 0.05). Multivariate analysis showed that age (p < 0.01, CI 1.02 to 1.15, odds ratio 1.1) and urea/creatinine ratio (p < 0.01, CI 1.03 to 1.38, odds ratio 1.2) were positively and independently related to outcome. In the early death group, malnutrition was an important cause of death (17% of all deaths). Compared to baseline data, long-term survivors, at the last follow up, presented reduced systolic blood pressure and increased hematocrit and unchanged body weight, serum albumin and urea/creatinine ratio. These results, based on easily accessible initial variables, suggest that early death on dialysis is influenced by age and by indices related to the nutritional condition of the patients. They also highlight the importance of a potentially correctable risk factor in a population with an elevated prevalence of premature death.