Okubo M, et al. - Researchers quantified the variation in patient outcomes following out-of-hospital cardiac arrest (OHCA) across emergency medical services (EMS) agencies in this cohort study. Findings revealed significant unexplained variation in survival rates following OHCA across EMS agencies in North America, irrespective of controlling for documented patient and agency characteristics.

Methods

• They conducted this observational cohort study in the Resuscitation Outcomes Consortium (ROC) Epistry, a prospective multicenter OHCA registry, at 10 sites in North America.
• They included any adult with OHCA treated by an EMS from April 2011 through June 2015.
• They analyzed data from May 2017 to March 2018.
• Treating EMS agency was included in the exposure.
• Survival to hospital discharge was the primary outcome.
• Return of spontaneous circulation at emergency department arrival and favorable functional outcome at hospital discharge (defined as a modified Rankin scale score of ≤ 3) were the secondary outcomes.
• In order to adjust confounders and clustering of patients within EMS agencies, multivariable hierarchical logistic regression models were used, and calculated median odds ratios (MORs) were used to quantify the extent of residual variation in outcomes between EMS agencies.

Results

• A total of 43,656 patients with OHCA treated by 112 EMS agencies were identified.
• The investigators observed large variations in survival to hospital discharge (range, 0% to 28.9%; unadjusted MOR, 1.43 [95% CI, 1.34-1.54]), return of spontaneous circulation on emergency department arrival (range, 9.0% to 57.1%; unadjusted MOR, 1.53 [95% CI, 1.43-1.65]), and favorable functional outcome (range, 0% to 20.4%; unadjusted MOR, 1.54 [95% CI, 1.40-1.73]) at the EMS agency level.
• Results demonstrated the persistence of variation despite adjustment for patient-level and EMS agency–level factors known to be associated with outcomes (adjusted MOR for survival 1.56 [95% CI 1.44-1.73]; adjusted MOR for return of spontaneous circulation at Emergency Department arrival, 1.50 [95% CI, 1.41-1.62]; adjusted MOR for functionally favorable survival, 1.53 [95% CI, 1.37-1.78]).
• This variation persisted even after restricting the analysis to those who survived > 60 minutes post-hospital arrival and including hospital treatment characteristics (adjusted MOR for survival, 1.49 [95% CI, 1.36-1.69]; adjusted MOR for functionally favorable survival, 1.34 [95% CI, 1.20-1.59]).