Association between serum uric acid to serum creatinine ratio with cardiovascular and all-cause mortality in adults with hypertension.

The serum uric acid to serum creatinine ratio (SUA/sCr) is a standardized index of renal function. More importance was attached to the significance of this ratio in the progression of hypertension. While the association between the prognosis of hypertension and SUA/sCr is unknown. Therefore, we aimed to prospectively examine the associations of serum uric acid to serum creatinine ratio and all-cause and CVD mortality in adults with hypertension. Participants with hypertension from NHANES 1999-2018 (n = 15,269) were included. They were stratified by 1 increment of SUA/sCr ratio and categorized into 6 groups as ≤ 4, > 4 to 5, > 5 to 6, > 6 to 7, > 7 to 8, and > 8. The reason for categorization in 6 groups was to analyze the influence of different ratios on outcomes accurately and provide more precise guidance. The sample size is large enough that even if divided into 6 groups, it does not affect the statistical power. The primary outcomes were all-cause and CVD mortality. Weighted multivariable Cox proportional hazards regression models were used to estimate hazard ratio (HRs) of mortality. Restricted cubic spline regression models were utilized to examine dose-response associations between the serum uric acid to serum creatinine ratio and all-cause and CVD mortality. Relatively comprehensive stratified analyses were conducted to confirm the accuracy and stability of the results. There were 15,269 total participants, 49.4% of whom were men, with an average age of 56.6 years. Weighted multivariable Cox proportional hazards regression models demonstrated participants in the lowest group (≤ 4) had the HRs (95% CIs) of 1.43 (1.18, 1.73) for all-cause mortality and 2.8 (1.92, 4.10) for CVD mortality when compared to the reference group. Participants in the highest group (> 8) had the HRs (95% CIs) of 0.47 (0.25, 0.89) for CVD mortality when compared to the reference group. There were progressively lower risks for all-cause and CVD mortality with the SUA/sCr ratio increased (both P trend < 0.01). The SUA/sCr ratio was (P for nonlinearity < 0.01) nonlinearly correlated with all-cause mortality, with inflection points of 6.25. In addition, the restricted cubic splines results indicated that the SUA/sCr ratio (P for nonlinearity = 0.32) showed linear and negative associations with cardiovascular mortality with inflection points of 6.54. The inverse associations between SUA/sCr ratio and all-cause mortality were consistent across all subgroups except for the subgroup of eGFR < 45 ml/min/1.73 m and never smokers (P trend = 0.20 and 0.13, respectively), and the inverse associations between low SUA/sCr ratio and CVD mortality were consistent across all subgroups (P trend < 0.01). Contrary to previous studies, outcomes suggest that lower SUA/sCr ratio was associated with higher risks of all-cause and CVD mortality in adults with hypertension.