Nonlinear dose-response relationship between red blood cell distribution width to platelet ratio and 90-day unfavorable outcomes in acute ischemic stroke: a prospective cohort study

Currently, there is relatively limited research regarding the relationship between the red blood cell distribution width to platelet ratio (RPR) and the prognosis of patients with acute ischemic stroke (AIS). Therefore, this study aims to investigate the association between RPR and the incidence of unfavorable functional outcomes in AIS patients. This study utilized a prospective cohort design and included 1,682 patients who had been diagnosed with AIS and were treated at Shenzhen Second People's Hospital from January 2022 to June 2024. To evaluate the relationship between RPR and the incidence of 90-day unfavorable outcomes, a binary logistic regression model was employed. Furthermore, an additional logistic regression model that included cubic spline functions was utilized to investigate possible nonlinear associations between them. A range of sensitivity analyses and subgroup analyses were conducted to strengthen the reliability of the results. After adjusting for confounding variables, the binary logistic regression analysis demonstrated that for each 0.1 unit increase in RPR, the incidence of unfavorable outcomes at 90 days for AIS patients increased by 45.5% (OR = 1.455, 95% CI: 1.268-1.669). Additionally, the study found a nonlinear relationship between RPR and 90-day unfavorable outcomes, with an inflection point occurring at RPR = 0.33. On the left side of the inflection point, the OR for the relationship between RPR (per 0.1 unit) and 90-day unfavorable outcomes was 1.708 (95% CI: 1.403-2.080). On the right side of the inflection point, the OR for their relationship was 0.942 (95% CI: 0.630-1.410). Sensitivity analysis further confirmed the reliability of these results. This study identifies a distinct positive link between RPR and 90-day unfavorable outcomes in patients with AIS. Additionally, a non-linear relationship was observed in the relationship between them. Specifically, when the RPR value falls below 0.33, a significant positive association is noted. These findings offer valuable insights for improving rehabilitation strategies and enhancing clinical management for AIS patients.