Sheng Chen ¹ Senhong Guan ¹ Zhaohan Yan ¹ Fengshan Ouyang ² Shuhuan Li ³ Lanyuan Liu ⁴ Liuer Zuo ^5* Yuli Huang ^1* Jiankai Zhong ^1*

• ¹ Department of Cardiology, Shunde Hospital, Southern Medical University, Foshan, Guangdong Province, China
• ² Department of Rehabilitation Medicine, Shunde Hospital, Southern Medical University, Foshan, Guangdong Province, China
• ³ Department of Pediatrics, Shunde Hospital, Southern Medical University, Foshan, Guangdong Province, China
• ⁴ Department of Ultrasound Medicine, Shunde Hospital, Southern Medical University, Foshan, Guangdong Province, China
• ⁵ Department of Intensive Care Unit, Shunde Hospital, Southern Medical University, Foshan, Guangdong Province, China

Background: The red blood cell distribution width (RDW)-to-albumin ratio (RAR) has emerged as a potentially valuable prognostic indicator in diverse medical conditions. However, the prognostic significance of RAR in intensive care unit (ICU) patients with coronary heart disease (CHD) and diabetes mellitus (DM) remains remains uncertain and requires further investigation. Methods: This study aims to investigate the prognostic significance of RAR in ICU patients with coexisting CHD and DM through a retrospective cohort analysis using data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database (version 2.2). The study population included patients aged 18 years or older who were diagnosed with both CHD and DM. The primary endpoint was 1-year mortality, and the secondary endpoints included 30-day mortality, 90-day mortality, hospital length of stay (LOS), and ICU LOS. Results: A total of 3416 patients, of whom 64.64% were male, were included in the study. The 30-day mortality, 90-day mortality, and 1-year mortality were 7.08%, 7.44%, and 7.49%, respectively. After adjusting for confounding factors, multivariate Cox proportional risk analysis demonstrated that high RAR levels were associated with an increased risk of 30-day mortality (HR, 1.53 [95% CI 1.17-2.07], P = 0.006), 90-day mortality (HR, 1.58 [95% CI 1.17-2.13], P = 0.003), and 1-year mortality (HR, 1.58 [95% CI 1.17-2.13], P = 0.003). Furthermore, the restricted cubic spline (RCS) model indicated a linear relationship between RAR and 1-year mortality. Conclusions: The results suggest that RAR holds potential as a valuable prognostic biomarker in ICU patients with both CHD and DM. Elevated RAR levels were found to be significantly associated with increased mortality during hospitalization, facilitating the identification of individuals at higher risk of adverse outcomes. These findings underscore the importance of incorporating RAR into risk stratification and overall management strategies for ICU patients with coexisting CHD and DM.