Association of serum uric acid to all-cause and cardiovascular mortality in patients with cardiovascular disease

Serum uric acid (SUA) has been linked to mortality in heart failure, hypertension, diabetes, hyperlipidemia, obstructive sleep apnea, and metabolic dysfunction-associated fatty liver disease. However, data are lacking on how it affects the mortality risk of patients with cardiovascluar disease (CVD). This study evaluated the data of 4 308 individuals from the National Health and Nutrition Examination Survey 1999-2008 using multivariate Cox proportional hazards regression, trend, restricted cubic splines (RCS), subgroup and inflection point analyses. All-cause and cardiovascular mortality accounted for 42.8% and 17.6% of cases, respectively, over a median 80- month follow-up. Upon control for confounding variables, no linear trend was seen in the Cox proportional hazards regression analysis between SUA and all-cause (P = 0.001) or cardiovascular death (P = 0.007) mortality. On the RCS analysis, SUA showed an L-shaped connection with all-cause (non-linear P < 0.001) and cardiovascular mortality (non-linear P = 0.003) mortality. On the inflection point analysis, patients with CVD and an SUA >= 6.127 mg/dL had an all-cause mortality hazard ratio of 1.146 (95% confidence interval, 1.078-1.217; P < 0.001), while those with CVD and an SUA >= 5.938 mg/dL had a cardiovascular mortality hazard ratio of 1.123 (95% confidence interval, 1.03-1.225; P = 0.007). In patients with CVD, higher SUA was non-linearly correlated with all-cause and cardiovascular mortality.