The effect of socioeconomic status on access to care and mortality following stroke

Abstract

36 Background: Socioeconomic status has been associated with increased mortality from ischemic heart disease as well as decreased access to interventions such as coronary angiography, even in countries with universal health care. We undertook a study to determine whether a similar association between socioeconomic status and mortality exists in the setting of stroke. Methods: We linked hospital discharge abstracts and vital-status data for all patients with acute stroke who were admitted to hospitals in Ontario between April 1994 and March 1997. Socioeconomic status for each patient was imputed based on their median neighborhood income as documented in Canada’s 1996 census. We determined the risk of death at thirty days and one year based on neighborhood income. Secondary analyses compared use of medications and carotid endarterectomy by income level. We used multivariate analyses to adjust for age, sex, stroke type, comorbid conditions and hospital and physician characteristics. Results: Overall, 39,545 patients were admitted with stroke during the study time frame. The crude 30-day and 1-year mortality rates were 19% and 33%, respectively. Thirty-day mortality was higher in those in the lowest income quintile than in the highest quintile (20% vs. 17%, P=0.002), with an adjusted hazard ratio of 1.1. One-year mortality was also higher in the lowest compared to the highest income quintile (34% vs. 31%, P=0.001), with an adjusted hazard ratio of 1.1. Each $10,000 increase in median neighborhood income was associated with a 9% reduction in the risk of death at 30 days (adjusted hazard ratio 0.91) and a 5% reduction in the risk of death at one year (adjusted hazard ratio 0.95). There were no differences in the use of medications (aspirin, ticlopidine, warfarin) or carotid endarterectomy based on socioeconomic status. However, waiting times for carotid surgery were significantly longer in the lowest income quintile compared to the highest (90 days vs. 60 days, P=0.001). Conclusion: Socioeconomic status affects mortality following stroke, even in a province with universal health care. The exact reasons for this effect on survival remain topics for future research.