Park C, et al. - Researchers presumed that normalized protein catabolic rate (nPCR), a dietary protein intake surrogate, modifies the link between serum uric acid (SUA) and mortality in the hemodialysis (HD) population. Findings of this study indicated that SUA may be a nutritional marker in HD patients. Importantly, contrary to the general population, an association of low but not high SUA with higher all-cause mortality was seen in HD patients, particularly in those with low protein intake.

Methods

• Researchers identified 4298 patients who initiated HD and had one or more SUA measurement in a contemporary cohort of HD patients over 5 years (1 January 2007–31 December 2011).
• They assessed survival probability according to the first uric acid measurement, adjusting for dialysis vintage, case-mix and malnutrition–inflammation complex-related variables.

Results

• Data showed that mean SUA concentration was 6.6 ± 1.8 mg/dL.
• Irrespective of adjusted models, a consistent association of higher SUA with better nutritional status and lower all-cause mortality was evident (P_trend < 0.001).
• In the case-mix adjusted model, researchers observed that no significant mortality risk [hazard ratio (HR) 0.90, 95% confidence interval (CI) 0.72–1.13] was demonstrated by the highest SUA category (≥8.0 mg/dL) versus the reference group (>6.0–7.0 mg/dL), while the lowest category (<5.0 mg/dL) was associated with higher mortality (HR 1.42, 95% CI 1.16–1.72).
• Findings also demonstrated that nPCR (P_interaction = 0.001) significantly modified the link between hypouricemia and mortality.
• In addition, among patients with low nPCR (<0.9 g/kg/day; HR 1.73, 95% CI 1.42–2.10) but not in those with high nPCR (≥0.9 g/kg/day; HR 0.99, 95% CI 0.74–1.33), mortality risk of low SUA (<5.0 mg/dL) persisted.