Serum C ‐reactive protein adds predictive information for post‐stroke delirium: The PROPOLIS study

Abstract Objective Delirium is common and serious complication after stroke. Accurate prediction of delirium is important for prevention and monitoring of high‐risk patients. Our study aimed to determine if addition of C‐reactive protein (CRP) to a model based on easy‐to‐access clinical predictors improves accuracy of delirium prediction in acute stroke patients. Methods We analyzed data of patients participating in the Prospective Observational Polish Study on post‐stroke delirium. We included patients admitted within 24 h after stroke or transient ischemic attack (TIA) in whom serum CRP was measured on admission. We examined core features of delirium during first 7 days of hospitalization. We assessed if addition of CRP to two clinical models improved metrics of discrimination and reclassification. Model A included age and stroke severity and Model B included stroke severity, atrial fibrillation, diabetes mellitus, pre‐stroke dependency, and hemorrhagic stroke. Results We included 459 patients. We diagnosed delirium in 29.2% of them. Patients who developed delirium had higher CRP level than those without delirium (median: 13.2 vs. 4.4 mg/L, p < 0.001). CRP >7.09 mg/L was associated with an increased risk of delirium (adjusted OR: 2.98, 95%CI: 1.71–5.19, p < 0.001). After adding CRP to clinical models, an area under receiver operator curve increased from 0.77 to 0.80 ( p = 0.038) for Model A and from 0.81 to 0.84 ( p = 0.016) for Model B. There was also improvement in reclassification. Conclusions Addition of CRP to clinical predictors moderately improved prediction of post‐stroke delirium. CRP could be considered as a potential biomarker to stratify risk of delirium after stroke.