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

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.