U-shaped relationship between cardiovascular mortality and serum uric acid may be attributed to stroke- And heart-specific mortality, respectively, among hypertensive patients: A nationally representative cohort study

Abstract

Background: Serum uric acid (UA) is involved in the development of hypertension. However, its impact on mortality in hypertension remains unclear. We aimed to assess the association of cardiovascular and all-cause mortality with UA in a hypertensive population. Material/Methods: This study included 15 583 hypertensive patients from the NHANES study during 1999-2014. Weighted Cox regression analyses and cubic spline fitting were used to assess the relationship between UA and mortality risk. Results: Over a median follow-up of 7.4 years (116 351 person-years), a total of 3291 deaths occurred. Mortality was examined according to 5 predefined UA levels: £3.5, 3.5–5, 5–6, 6–7.5, and >7.5 mg/dL. In multivariable analysis with 5–6 mg/dL as a reference, the hazard ratios (95% confidence interval) of total mortality across the 5 groups were 1.40 (1.05–1.88), 1.08 (0.95–1.21), 1.00 (reference), 1.14 (1.02–1.29), and 1.74 (1.50–2.02), respectively. According to a restricted cubic spline, we noted a U-shaped relationship between UA and total mortality. The U-shaped relationship between UA and cardiovascular mortality remained in both females and males. The increased cardiovascular mortality in the lowest and highest UA groups was attributed to stroke and heart-specific mortality, respectively. However, serum UA was not significantly associated with cancer mortality. Conclusions: Our findings showed a U-shaped relationship between serum UA levels and total and cardiovascular mortality in patients with hypertension. Furthermore, low UA was associated with stroke mortality, while higher UA was associated with heart-related mortality. Further research is needed to identify the potential mechanisms of UA in hypertension.