Jin Wang, Yaxin Zhang, Yadong Wu, Shulan Lin, Fan Wu, Shuqi Lin, Min Zhang, Weihong Zheng
RAR was independently associated with pneumonia during ICU stay among patients with AIS. As a readily available and low-cost biomarker, RAR may serve as an adjunctive marker for early risk stratification. However, its discriminatory performance was modest, and its clinical value beyond established predictors remains uncertain. Prospective studies are needed to confirm these findings.
BACKGROUND: Pneumonia is a common and severe complication in acute ischemic stroke (AIS) patients, particularly those requiring intensive care. Early prediction of pneumonia risk can enable timely interventions and improve clinical outcomes. The Red Blood Cell Distribution Width to Albumin Ratio (RAR), combining markers of inflammation (RDW) and nutritional status (albumin), has potential as a predictor of pneumonia risk in AIS patients.
METHODS: This retrospective cohort study included AIS patients from MIMIC-IV (n = 1,266) and XMHH (n = 294). Pneumonia incidence was compared across tertiles of RAR. The relationship between RAR and pneumonia was assessed using multivariable logistic regression. Restricted cubic splines (RCS) were used to explore the non-linear relationship between RAR and pneumonia risk. Predictive performance was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC). E-value analysis was performed to assess the robustness of the association and the impact of unmeasured confounders.
RESULTS: Elevated RAR was significantly associated with an increased risk of pneumonia in both cohorts. In the MIMIC-IV cohort, the incidence of pneumonia was higher in the highest RAR group (T3) compared to the lowest (T1) (21.75% vs. 7.11%, p < 0.001). In fully adjusted model, the OR for pneumonia in the highest RAR group was 2.11 (1.30-3.41). A similar trend was observed in the XMHH cohort, with an OR of 3.94 (1.27-12.27). Exploratory subgroup analyses suggested that the association between RAR and pneumonia appeared more pronounced among patients without atrial fibrillation and without renal disease in the MIMIC-IV cohort; however, these findings were not replicated in the XMHH cohort and should be interpreted cautiously.
CONCLUSION: RAR was independently associated with pneumonia during ICU stay among patients with AIS. As a readily available and low-cost biomarker, RAR may serve as an adjunctive marker for early risk stratification. However, its discriminatory performance was modest, and its clinical value beyond established predictors remains uncertain. Prospective studies are needed to confirm these findings.