Racial differences in long-term outcomes among older survivors of in-hospital cardiac arrest

Abstract

Background: Black patients have worse in-hospital survival than white patients after in-hospital cardiac arrest (IHCA), but less is known about long-term outcomes. We sought to assess among IHCA survivors whether there are additional racial differences in survival after hospital discharge and to explore potential reasons for differences. Methods: This was a longitudinal study of patients ≥65 years of age who had an IHCA and survived until hospital discharge between 2000 and 2011 from the national Get With The Guidelines–Resuscitation registry whose data could be linked to Medicare claims data. Sequential hierarchical modified Poisson regression models evaluated the proportion of racial differences explained by patient, hospital, and unmeasured factors. Our exposure was black or white race. Our outcome was survival at 1, 3, and 5 years. Results: Among 8764 patients who survived to discharge, 7652 (87.3%) were white and 1112 (12.7%) were black. Black patients with IHCA were younger, more frequently female, sicker with more comorbidities, less likely to have a shockable initial cardiac arrest rhythm, and less likely to be evaluated with coronary angiography after initial resuscitation. At discharge, black patients were also more likely to have at least moderate neurological disability and less likely to be discharged home. Compared with white patients and after adjustment only for hospital site, black patients had lower 1-year (43.6% versus 60.2%; relative risk [RR], 0.72), 3-year (31.6% versus 45.3%; RR, 0.71), and 5-year (23.5% versus 35.4%; RR, 0.67; all P<0.001) survival. Adjustment for patient factors explained 29% of racial differences in 1-year survival (RR, 0.80; 95% confidence interval, 0.75–0.86), and further adjustment for hospital treatment factors explained an additional 17% of racial differences (RR, 0.85; 95% confidence interval, 0.80–0.92). Approximately half of the racial difference in 1-year survival remained unexplained, and the degree to which patient and hospital factors explained racial differences in 3-year and 5-year survival was similar. Conclusions: Black survivors of IHCA have lower long-term survival compared with white patients, and about half of this difference is not explained by patient factors or treatments after IHCA. Further investigation is warranted to better understand to what degree unmeasured but modifiable factors such as postdischarge care account for unexplained disparities.