Urinary albumin-to-creatinine ratio as an independent predictor of long-term mortality in atherosclerotic cardiovascular disease patients: A propensity score-matched study: UACR and Long-term Mortality in ASCVD.

Background And Aims: Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of mortality, and while the association between the urinary albumin-to-creatinine ratio (UACR) and cardiovascular risk is recognized, the specific impact of UACR on the long-term survival of ASCVD patients remains not fully understood. The aim of this study is to investigate the influence of UACR on the long-term risk of all-cause mortality in patients with ASCVD.

Methods: This study included ASCVD patients from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Mortality outcomes were ascertained by linkage to the National Death Index as of December 31, 2019. UACR risk was stratified into three levels: Group 0 (UACR < 30 mg/g), Group 1 (30-300 mg/g), and Group 2 (>300 mg/g). The primary outcome was all-cause mortality, with cardiovascular mortality as a secondary outcome. Cox proportional hazards, adjusted for demographic factors, traditional cardiovascular risk factors, and secondary prevention medications for ASCVD, were used to analyze the cumulative risk of outcomes. Propensity score matching was employed for risk adjustment, and sensitivity analyses were conducted based on cohorts with chronic coronary syndrome (CCS), stroke, heart failure, and non-heart failure.

Results: Among the 1,737 patients with a median follow-up of 10 years, 1,026 all-cause deaths and 351 cardiovascular deaths were recorded. After full model adjustment, higher UACR levels were associated with increased risks of all-cause mortality (Group 1: hazard ratio (HR), 1.601; 95 % confidence interval (CI), 1.382-1.855; Group 2: HR, 2.378; 95 % CI, 1.884-3.001; both < 0.001 for trend) and cardiovascular mortality (Group 1: HR, 2.080; 95 % CI, 1.631-2.652; Group 2: HR, 2.883; 95 % CI, 1.951-4.260; both < 0.001 for trend). Propensity score matching confirmed these findings, showing significantly elevated all-cause mortality risks in high-risk UACR groups (with a cutoff of 30 mg/g: HR, 1.468 (95 %CI, 1.254-1.719), < 0.001; with a cutoff of 300 mg/g: HR, 1.935 (95 %CI, 1.399-2.675), < 0.001). All sensitivity analyses were consistent with the results of the overall cohort.

Conclusion: UACR is an important prognostic indicator for predicting the long-term outcomes of ASCVD patients, with its impact being independent of eGFR.