Purpose: To evaluate the value of the combination of the age, atrial fibrillation, dysphagia, male sex, and National Institutes of Health Stroke Scale (A²DS²) score and serum interleukin 6 (IL-6) concentration in predicting stroke-associated pneumonia (SAP).
Patients and Methods: A total of 398 patients with acute ischemic stroke (AIS) from the medical ward was included in this retrospective study. They were divided into the SAP group and non-SAP group according to the diagnostic criteria of SAP. Multivariate analysis was performed to analyze the association between the A²DS² score, serum IL-6 concentration, and SAP using a backward stepwise logistic regression model. The receiver operating characteristic (ROC) curve was used to evaluate the value of the A²DS² score, serum IL-6 concentration and combination of A²DS² score and IL-6 in predicting SAP.
Results: SAP was diagnosed in 70 patients (17.6%). Multivariate analysis showed that the A²DS² score (odds ratio [OR ]: 2.25, 95% confidence interval [CI ]: 1.17– 4.99, P =0.017) and serum IL-6 concentration (OR : 1.76, 95% CI : 1.44– 1.95, P < 0.001) was independently associated with SAP after adjusting for age, smoking, hypertension, hyperlipidemia, and atrial fibrillation. When the A²DS² score, serum IL-6 concentration and combination of A²DS² score and IL-6 were employed to predict SAP, the AUC was 0.824 (SE : 0.026, 95% CI : 0.773– 0.875), 0.715 (SE : 0.034, 95% CI : 0.641– 0.788) and 0.917 (SE : 0.015, 95% CI : 0.887– 0.946), respectively. The AUC of combinative prediction was significantly higher than independent prediction (0.917 vs. 0.824, Z =3.098, P < 0.001; 0.917 vs. 0.715, Z =5.436, P < 0.001).
Conclusion: The addition of serum IL-6 to the A²DS² score could significantly enhance the AUC of predicting SAP in AIS patients from the medical ward.
Keywords: stroke-associated pneumonia; SAP, A²DS² score, interleukin 6, multivariate analysis, receiver operating characteristic curve; ROC