Identification of red cell distribution width trajectory patterns and their association with 28-day mortality in intensive care unit patients with atrial fibrillation: A latent class analysis

Background Red cell distribution width (RDW) has been identified as a potential prognostic marker in multiple cardiovascular and critical illnesses. Nevertheless, its prognostic value, particularly regarding changes in RDW over time among patients with atrial fibrillation (AF), remains uncertain. Methods A retrospective cohort study was conducted using data from the Medical Information Mart for Intensive Care (MIMIC)-IV database. The study included adult intensive care unit (ICU) patients with AF who had at least three RDW measurements within the first 36 h of ICU admission. Latent growth mixture modeling (LGMM) was applied to identify distinct RDW progression patterns over time. The association between the identified RDW trajectory groups and 28-day mortality was assessed using Cox proportional hazard regression. Kaplan–Meier survival curves and subgroup analyses were also conducted. Results A total of 3509 patients were enrolled in the analysis. LGMM identified three distinct RDW trajectories: Class 1 (stable and low RDW), Class 2 (moderate with a rising RDW) and Class 3 (high with fluctuating RDW). After adjusting for demographics, clinical parameters, comorbidities and treatments, Class 2 remained independently associated with higher 28-day mortality compared with Class 1 ( P = 0.003). No significant difference was observed between Class 3 and Class 1. Kaplan–Meier analysis confirmed significant differences in survival among the classes ( P < 0.001). Subgroup analysis showed consistent associations without significant interactions. Conclusion RDW trajectory patterns are independently associated with 28-day mortality in critically ill AF patients and may serve as valuable prognostic indicators in this population.