Relation Between the Incidence of In-Hospital Cardiac Arrest and Survival in Older Patients

Survival after an in-hospital cardiac arrest (IHCA) varies markedly across U.S. hospitals. Whether hospitals with high IHCA survival also excel in "preventing" IHCA, and the extent to which both outcomes are associated with hospital variables, remains unclear.

This study sought to examine the correlation between hospital IHCA incidence and survival and to evaluate the association of hospital variables with both outcomes.

In this observational cohort study, we used 2013-2019 Get With The Guidelines-Resuscitation data linked with Medicare and American Hospital Association data to identify all patients ≥65 years with IHCA at participating hospitals. We calculated hospital rates of IHCA incidence adjusted for case-mix index and risk-standardized rate of survival to discharge (RSSR) for IHCA adjusted for patient variables using hierarchical multivariable regression models. We used linear regression to examine the association between hospital IHCA incidence and RSSR and to evaluate their association with hospital variables.

Among >10 million Medicare admissions at 335 hospitals, 77,676 patients experienced an IHCA between 2013 and 2019. After case-mix adjustment, the median IHCA incidence was 7.9 per 1,000 admissions (Q1-Q3: 5.9-10.3 per 1,000 admissions; range: 1.2-25.9 per 1,000 admissions) and the median RSSR was 22.3% (Q1-Q3: 19.5%-24.9%; range: 11.5%-35.7%). Before considering hospital characteristics, there was a modest negative correlation between case-mix adjusted IHCA incidence and RSSR (ρ = -0.12; P = 0.03). Additional adjustment for hospital variables attenuated the negative association between IHCA incidence and RSSR (ρ = -0.08; P = 0.13). A higher nurse-patient ratio was the only modifiable variable significantly associated with lower IHCA incidence and higher RSSR.

Hospital IHCA incidence rates were only modestly correlated with IHCA survival rates, suggesting that hospital IHCA incidence rates can be considered an independent quality metric. Given that IHCA survival has plateaued in recent years, efforts to reduce IHCA incidence rates, such as higher nurse-staffing, may yield additional gains in reducing IHCA deaths.