Trajectories of urea‑to‑creatinine ratio and risk of clinical outcomes in survivors of acute kidney disease: a population-based study.

Abstract

Background: The urea-to-creatinine ratio (UCR) serves as a common metric for assessing dehydration, catabolism, excessive protein intake and impaired kidney perfusion. However, the performance of UCR in patients with acute kidney disease (AKD) remains unexplored.

Methods: In this retrospective cohort study, we enrolled 6703 survivors of AKD from a nationwide population-based database in Taiwan linked with laboratory data from 1 January 2015 to 31 December 2018. Using a group-based trajectory model (GBTM), we identified UCR trajectories and investigated their dynamic changes. We associated these trajectories with major adverse kidney events (MAKEs) as the primary outcome, and mortality and major adverse cardiovascular events (MACEs) as secondary outcomes in AKD survivors.

Results: A total of 9717 AKD survivors were enrolled with a mean follow-up of 1.3 ± 0.9 years. The incidence of MAKEs was 43.7%, the incidence of mortality was 26.3% and the incidence of MACEs was 31.1%. After adjusting for known covariates, UCR trajectories independently predicted MAKEs, all-cause mortality and MACEs. Compared with the middle trajectory group, the high UCR trajectory group had a significantly elevated risk of MAKEs [hazard ratio (HR) 1.54, 95% confidence interval (CI) 1.38-1.73], mortality rate (HR 1.59, 95% CI 1.41-1.80) and MACEs (HR 1.57, 95% CI 1.40-1.77). In contrast, the low UCR trajectory group had an increased risk of MAKEs (HR 1.30, 95% CI 1.20-1.41) and a reduced risk of mortality rate (HR 0.84, 95% CI 0.74-0.95).

Conclusions: Distinct UCR trajectories predicted MAKEs, all-cause mortality and MACEs in AKD survivors. A high UCR trajectory was associated with the highest risk of adverse events, whereas a low UCR trajectory carried a higher risk of MAKEs but a lower risk of mortality. These findings underscore the clinical relevance of monitoring UCR trajectories for long-term prognosis and risk stratification in AKD patients.