High uric acid concentrations are associated with lower all-cause and cardiovascular mortality among hemodialysis (HD) patients, according to an international study.
The findings contrast with those of studies of individuals in the general population and “raise the possibility that higher uric acid concentrations may be cardioprotective in dialysis patients,” researchers concluded in the Clinical Journal of the American Society of Nephrology (2011;6;2470-2477).
In a study of 5,827 HD patients from six countries, those with uric acid levels below 8.2 mg/dL had a 24% and 54% increased risk of all-cause and cardiovascular mortality, respectively, compared with patients who had higher uric acid levels, after adjusting for multiple variables. Each 1 mg/dL increment in uric acid was associated with a 5% decreased risk of all-cause mortality and 8% decreased risk of cardiovascular mortality.
In addition, the study showed that younger age, higher body mass index, residual renal function, and diuretic use were significant predictors of high uric acid (above 8.2 mg/dL).
The investigators, led by Rajiv Saran, MD, of the University of Michigan in Ann Arbor, examined data from patients who participated in the Dialysis Outcomes and Practice Patterns Study (DOPPS), which is administered by Arbor Research Collaborative for Health.
Dr. Saran’s group noted that the paradoxical association between high uric acid and lower all-cause and cardiovascular mortality is yet another example of so-called “reverse epidemiology” in the dialysis population.
They speculate that higher uric acid among hemodialysis patients is a surrogate for better nutritional status.