Predictors of mortality in long-term haemodialysis patients with a low prevalence of comorbid conditions

Background. Total and cardiovascular mortality rates for haemodialysis patients are still high despite the continuous improvement of dialysis technology. This trend may be a consequence of the increased number of elderly patients and patients with concurrent systemic diseases admitted to dialysis programmes. The objective of the present investigation was to determine the predictors of mortality more closely related to uraemic status and to dialysis treatment by studying relatively young haemodialysis patients with a low prevalence of comorbid conditions using the Cox proportional hazards model. Methods. Seventy-four haemodialysis patients with a low prevalence of extrarenal diseases (mean age 44.5±12.1 years, mean dialysis duration 51.3±36.1 months) were submitted to extensive cardiological and clinical evaluation and followed prospectively for a median period of 60.8 months (range : 5.1-79.8). There were only three diabetics and all patients denied previous myocardial infarction. Results. At follow-up 23 patients had died, 10 of cardiac causes. Five-year survival rates were 70% for overall mortality and 83% for cardiac mortality. Age over 44 years (relative risk 3.73 ; 95% confidence interval 1.35-10.26) and serum creatinine (inverse correlation) (relative risk 0.73 ; 95% confidence interval 0.57-0.94) were shown to be independently associated with global mortality by the Cox proportional hazards analysis. Gender, race, dialysis duration, interdialytic weight gain, angina, NYHA classification, hypertension, LV hypertrophy, LV systolic and diastolic dysfunction, complex ventricular arrhythmias and altered myocardial perfusion tests were not significant predictors of overall mortality. There were crude associations between cardiac mortality and cardiothoracic and Sokolow indices (P<0.01) and age, NYHA classification, systolic hypertension, LV wall and septum hypertrophy, LV dilatation and complex ventricular arrhythmias (P<0.05). Conclusion. In the absence of serious comorbid conditions, the survival of patients on long-term haemodialysis is influenced by nutritional status (as indicated by lower serum creatinine) and age.