Serum urea-creatinine ratio as a prognostic index in hemodialysis patients

The role of the molar ratio of serum urea and creatinine concentrations (urea-creatinine ratio) as a variable affecting survival was studied in a series of 134 hemodialysis patients. The two-year survival rate was 78.4% for patients with a urea-creatinine ratio under 25.5 (lowest tertile) and 42.1% for patients with a urea-creatinine ratio over 31.3 (highest tertile). The correlation of the urea-creatinine ratio and survival was investigated by forming exponential models involving potential confounding factors. The relationship between the urea-creatinine ratio and survival did not disappear after adjusted by age, sex, blood pressure, body mass index and primary renal disease. The goodness of the fit of the exponential model for survival was significantly poorer if the urea-creatinine ratio, diastolic blood pressure and patients' age were deleted. Thus these factors had a marked and independent effect on survival. The relative risk of death was 1.8 for patients with a urea-creatinine ratio of 30 and 3.4 for patients with a urea-creatinine ratio of 40 when the risks of death were compared with the situation in which the urea-creatinine ratio was 20. The urea-creatinine ratio seems to play a role in predicting the survival of hemodialysis patients. It may thus be one of the very few survival affecting factors which can be influenced by active procedures.