Prognostic value of red blood cell distribution width-to-albumin ratio in patients with stable coronary artery disease stratified by glucose metabolic status: a prospective cohort study

Background and purpose: The red blood cell distribution width-to-albumin ratio (RAR) has emerged as a prognostic marker in various cardiovascular conditions. This investigated the association between RAR and cardiovascular outcomes in patients with stable coronary artery disease (SCAD), with a focus on variations across glucose metabolism status, a relationship not previously explored. Methods: A cohort of 4,266 consecutive SCAD patients was recruited and stratified into quartiles based on RAR levels. All participants were regularly monitored for major adverse cardiovascular events (MACEs), encompassing cardiovascular mortality, non-fatal myocardial infarction, and ischemic stroke. Cox regression analyses and glucose metabolic stratification were employed to assess the correlation between RAR and MACEs. Results: Over a mean follow-up of 52.77 ± 20.13 months, 287 MACEs were documented. Multivariate Cox regression analysis revealed a significant association between RAR and MACEs, both as a continuous variable and across quartiles. Patients in the third (Q3) and fourth (Q4) RAR quartiles exhibited a 1.92-fold (95% confidence interval [95% CI]: 1.05–3.52) and 2.01-fold (95% CI: 1.10–3.69) increased risk of MACEs, respectively, compared to those in the first quartile (Q1). Stratified analysis by glucose metabolic status further demonstrated that the correlation between higher RAR and MACEs was primarily observed among individuals with abnormal glucose regulation (AGR), particularly in those with diabetes mellitus. Conclusions: RAR served as a robust predictor of MACE risk in SCAD patients, with enhanced prognostic significance in individuals with AGR, especially in those with diabetes mellitus. These findings highlight RAR’s potential as a simple and effective risk stratification tool for high-risk SCAD patients.