Can a novel clinical risk score improve pneumonia prediction in acute stroke care? A UK multicenter cohort study

Background: pneumonia frequently complicates stroke and has amajor impact on outcome.wederived and internally validated a simple clinical risk score for predicting stroke-associated pneumonia (sap),and compared the performance with an existing score (a2ds2). methods and results--we extracted data for patients with ischemic stroke or intracerebral hemorrhage from the sentinel stroke national audit programme multicenter uk registry. the data were randomly allocated into derivation (n=11 551) and validation (n=11 648) samples. a multivariable logistic regression model was fitted to the derivation data to predict sap in the first 7 days of admission. the characteristics of the score were evaluated using receiver operating characteristics (discrimination) and by plotting predicted versus observed sapfrequency in deciles of risk (calibration). prevalence ofsapwas 6.7% overall. the final 22-point score (isan: prestroke independence [modified rankin scale],sex,age,national institutes of health stroke scale) exhibited good discrimination in the ischemic stroke derivation (c-statistic 0.79; 95% ci 0.77 to 0.81) and validation (c-statistic 0.78; 95% ci 0.76 to 0.80) samples. it was well calibrated in ischemic stroke andwas further classified intomeaningful risk groups (low0 to 5,medium6 to10,high 11 to 14,and very high =15) associated with sap frequencies of 1.6%,4.9%,12.6%,and 26.4%,respectively,in the validation sample. discrimination for both scores was similar,although they performed less well in the intracerebral hemorrhage patients with an apparent ceiling effect. conclusions-the isan score is a simple tool for predicting sap in clinical practice. external validation is required in ischemic and hemorrhagic stroke cohorts. © 2015 the authors. published on behalf of the american heart association,inc.,by wiley blackwell.