Hyperuricemia Is an Independent Risk Factor for Mortality Only if Chronic Kidney Disease Is Present

Abstract

Background/Aims: Hyperuricemia has been considered a risk factor for renal disease and cardiovascular disease. However, the potential contribution of hyperuricemia to mortality remains uncertain, and the results in the available literature vary according to kidney function. The aim of this study was to determine the association between hyperuricemia and mortality in patients undergoing percutaneous coronary intervention (PCI) across the interaction of kidney function. Method: We retrospectively reviewed patients who underwent PCI from 2003 to 2009. Propensity scores for hyperuricemia (>7 mg/dl for males and >6 mg/dl for females) were used to assemble a matched cohort of 693 pairs of patients with and without hyperuricemia for analysis from the 3,201 patients who fulfilled the inclusion criteria among the 4,842 patients who underwent PCI. Results: Of the 3,201 patients who underwent PCI and for whom data were available regarding their baseline serum uric acid level, 763 (23.8%) had hyperuricemia. The hyperuricemia-associated hazard ratios (HRs) [95% confidence intervals (CIs)] for all-cause mortality were 1.780 (1.270-2.495) in the unmatched cohort and 1.655 (1.109-2.468) in the matched cohort. The HRs (95% CI) for all-cause mortality among those with and without chronic kidney disease (CKD) were 2.080 (1.318-3.283) and 1.592 (0.778-3.256), respectively (p for interaction, 0.001). Conclusions: Hyperuricemia is an independent risk factor for all-cause mortality in those patients with CKD but not in those without CKD.

Pre- and Postdialysis Uric Acid Difference and Risk of Long-Term All-Cause and Cardiovascular Mortalities in Japanese Hemodialysis Patients; Miyazaki Dialysis Cohort Study

“…In the present study, a J-shaped relationship was observed, but was not significant. In contrast, elevated SUA levels are associated with an increased risk of mortality in the general population [6] and in nondialyzed chronic kidney disease patients [7][8][9]. These results are in contrast to previous findings obtained in the general population and suggest that higher UA levels are protective against mortality in dialysis patients.…”

“…Elevated levels of serum UA (SUA) are associated with an increased risk of mortality in the general population [6] and in nondialyzed chronic kidney disease patients [7][8][9]. Few studies have examined UA as a predictor of outcomes in HD patients, and controversy surrounds whether SUA is an independent risk factor for mortality in patients receiving HD [4,10,11].…”

Uric Acid and Cardiovascular Events

“…Regarding all-cause mortality and cardiovascular mortality, most studies find that serum UA is an independent predictor of cardiovascular end points, especially in patients with CAD, 17,30,[33][34][35] but some studies reported the opposite. 29,36,37 Possible explanations for diverging results could be sex-specific effects, 38 an interaction with kidney function, 39 or the possibility that UA might turn pro-oxidant under certain conditions (e.g., CAD). 40 In the LURIC study, the UA concentration is associated with CVD and SCD after multivariate adjustment.…”

Hyperuricemia is an Independent Predictive Factor for Left Ventricular Diastolic Dysfunction in Patients with Chronic Kidney Disease

“…Still other controversial appear in patients with CKD who have elevated levels of UA due to both the increased production and reduced excretion by kidney damage. In some studies hyperuricemia was an independent predictor of increased mortality only in patients with CKD [30,31], in other studies this was found only in patients with normal renal function [25,32]. Most of these trials evaluated the impact of hyperuricemia on the prognosis patients, the rate of hospitalizations and occurrence of adverse events.…”