Serum uric acid to creatinine ratio is a useful predictor of all-cause mortality among hypertensive patients

Abstract

Background: Many of the existing research studies have shown that serum uric acid (SUA) is a predictor of renal disease progression. More recently, studies have suggested an association between renal function-normalized SUA and all-cause mortality in adults. This study aims to examine the association between the ratio of SUA to creatinine (SUA/Cr) and all-cause mortality with a focus on hypertensive patients. Methods: This study is based on 2,017 participants, of whom 916 were male (mean age, 67 ± 11 years) and 1,101 were female (mean age, 69 ± 9 years). All participants were part of the Nomura Cohort Study in 2002 (cohort 1) and 2014 (cohort 2), as well as the follow-up period (2002 follow-up rate, 94.8%; 2014 follow-up rate, 98.0%). We obtained adjusted relative risk estimates for all-cause mortality from a basic resident register. In addition, we employed a Cox proportional hazards model and adjusted it for possible confounders to determine the hazard ratio (HR) and 95% confidence interval (CI). Results: Of the total participants, 639 (31.7%) were deceased; of these, 327 (35.7%) were male and 312 (28.3%) were female. We found an independent association between a higher ratio of SUA/Cr and a higher risk of all-cause mortality in female participants only (HR, 1.10; 95% CI, 1.02–1.18). The multivariable-adjusted HRs (95% CI) for all-cause mortality across quintiles of baseline SUA/Cr were 1.28 (0.91–1.80), 1.00, 1.38 (0.95–1.98), 1.37 (0.94–2.00), and 1.57 (1.03–2.40) for male participants, and 0.92 (0.64–1.33), 1.00, 1.04 (0.72–1.50), 1.56 (1.06–2.30), and 1.59 (1.06–2.38) for female participants. When the data were further stratified on the basis of age (< 65 or ≥ 65 years), body mass index (< 22.0 or ≥ 22.0 kg/m2), estimated glomerular filtration rate (< 60 or ≥ 60 mL/min/1.73 m2), and presence of SUA-lowering medication, trends similar to those of the full population were found in all groups. Conclusion: Baseline SUA/Cr is independently and significantly associated with future all-cause mortality among hypertensive patients.