Effect of Socioeconomic Status on Inpatient Mortality and Use of Postacute Care After Subarachnoid Hemorrhage

Abstract

Studies in the United States and Canada have demonstrated socioeconomic gradients in outcomes of acute life-threatening cardiovascular and cerebrovascular diseases. The extent to which these findings are applicable to subarachnoid hemorrhage is uncertain. This study investigated socioeconomic status-related differences in risk of inpatient mortality and use of institutional postacute care after subarachnoid hemorrhage in the United States and Canada. Subarachnoid hemorrhage patient records in the US Nationwide Inpatient Sample database (2005-2010) and the Canadian Discharge Abstract Database (2004-2010) were analyzed separately, and summative results were compared. Both databases are nationally representative and contain relevant sociodemographic, diagnostic, procedural, and administrative information. We determined socioeconomic status on the basis of estimated median household income of residents for patient's ZIP or postal code. Multinomial logistic regression models were fitted with adjustment for relevant confounding covariates. The cohort consisted of 31,631 US patients and 16,531 Canadian patients. Mean age (58 years) and crude inpatient mortality rates (22%) were similar in both countries. A significant income-mortality association was observed among US patients (odds ratio, 0.77; 95% CI, 0.65-0.93), which was absent among Canadian patients (odds ratio, 0.97; 95% CI, 0.85-1.12). Neighborhood income status was not significantly associated with use of postacute care in the 2 countries. Socioeconomic status is associated with subarachnoid hemorrhage inpatient mortality risk in the United States, but not in Canada, although it does not influence the pattern of use of institutional care among survivors in both countries.