Association between red blood cell distribution width to albumin ratio (RAR) and long-term prognosis of patients with sudden cardiac arrest.

Background: Red blood cell distribution width to albumin ratio (RAR) is associated with adverse outcomes in a variety of clinical conditions. However, the potential connection between RAR and the prognostic outcome of patients with sudden cardiac arrest (CA) remains uncharted. Hence, this study emphasizes elucidating the relevance between RAR and adverse prognosis in patients with sudden CA. Methods: Our study, a retrospective cohort analysis, used data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) version 3.0 database. The 1-year mortality rate was the principal endpoint of this study, the subordinate outcomes included the 5-year, 28-day, 90-day, and in-hospital mortality rates. Cox models, cubic spline models, and subgroup analyses assessed the link between RAR and mortality rates. Results: This study included a total of 1,673 participants. The study found that in the groups with in-hospital, 28-day, 90-day, 1-year and 5-year death rates, the median RAR of those who passed away was notably higher than that of those who survived. When the participants were grouped based on RAR tripartite number, it was observed that in the higher RAR groups, the numbers of deaths at various intervals (in-hospital, 28-day, 90-day, 1-year, and 5-year) showed significant increases. After adjusting for other factors, it was discovered that for the 1-year death rate, the risk was 1.27 times higher in the Q2 group (4.51-5.77) and 1.42 times higher in the Q3 group (>5.77) (with a confidence level of 95%), showing statistical significance. Similar patterns were found in the 28-day, 90-day, and 5-year death rates. However, this pattern was not seen in patients with in-hospital mortality. Besides, the analysis indicated a significant nonlinear relationship between RAR and the 1-year, 5-year death rate. The model constructed using the variables selected through least absolute shrinkage and selection operator (Lasso) regression analysis for predicting the clinical prognosis of patients with sudden CA demonstrated good discriminative ability, accuracy, and clinical utility. Conclusions: Our research has found a close association between RAR and the long-term adverse clinical outcomes of patients with sudden CA. The higher the RAR, the higher the mortality rates at 28 days, 90 days, 1 year and 5 years. A clinical model based on RAR for predicting the prognosis of patients with sudden CA can provide a convenient and accurate scoring system for evaluating their prognosis.