Background Thirty-day mortality after hospitalization for stroke is commonly reported as a quality indicator. However, the impact of adjustment for individual and/or neighborhood sociodemographic status ( SDS ) has not been well documented. This study aims to evaluate the role of individual and contextual sociodemographic determinants in explaining the variation across hospitals in Norway and determine the impact when testing for hospitals with low or high mortality. Methods and Results Patient Administrative System data on all 45 448 patients admitted to hospitals in Norway with an incident stroke diagnosis from 2005 to 2009 were included. The data were merged with data from several databases to obtain information on vital status (dead/alive) and individual SDS variables. Logistic regression models were compared to estimate the predictive effect of individual and neighborhood SDS on 30-day mortality and to determine outlier hospitals. All individual SDS factors, except travel time, were statistically significant predictors of 30-day mortality. Of the municipal variables, only the municipal variable proportion of low income was statistically significant as a predictor of 30-day mortality. Including sociodemographic characteristics of the individual and other characteristics of the municipality improved the model fit. However, performance classification was only changed for 1 (out of 56) hospital, from "significantly high mortality" to "nonoutlier." Conclusions Our study showed that those stroke patients with a lower SDS have higher odds of dying after 30 days compared with those with a higher SDS , although this did not have a substantial impact when classifying providers as performing as expected, better than expected, or worse than expected.
Keywords: health disparities; hospital performance; quality indicators; socioeconomic position; statistical model.