Variation in survival after out-of-hospital cardiac arrest between receiving hospitals in Japan: an observational study

Abstract

Objectives: Patient outcomes after out-of-hospital cardiac arrest (OHCA) varies at multilevel (geographical regions, emergency medical service agencies and receiving hospitals) in the USA. However, it remains unclear whether there is a variation in patient outcomes after OHCA between relevant units of the healthcare system such as receiving hospitals in Japan. Therefore, we aimed to quantify the variation in patient outcomes after OHCA between receiving hospitals in Japan.

Design: Secondary analysis of the prospective multicentre OHCA registry.

Setting: The Japan Association for Acute Medicine OHCA Registry, a prospective multicentre OHCA registry, including 73 medical institutions in Japan.

Participants: 9303 adults (≥18 years old) with OHCA of medical origin, treated at 67 hospitals from June 2014 to December 2015.

Primary and secondary outcome measures: The primary outcome was 1-month survival after OHCA. The secondary outcome was favourable functional status at 1 month, defined as cerebral performance category scale 1 or 2. We constructed a series of multivariable hierarchical logistic regression models predicting outcomes, accounting for patient-level variables and clustering of patients within hospitals. We evaluated the adjusted 1-month survival and functional outcome for each hospital, ranked hospitals for each outcome and calculated median ORs (MORs) to quantify the between-hospital variation in outcomes.

Results: The prevalence of 1-month survival after OHCA was 7.1% (663/9303) and that of favourable functional outcome was 3.6% (331/9303). After adjustment for patient-level factors, we observed variations in 1-month survival (range, 1.6%-13.8%; adjusted MOR 1.34; 95% CI 1.16 to 1.67) and favourable functional outcome (range, 0.7%-7.3%; adjusted MOR 1.53; 95% CI 1.10 to 2.24) between hospitals.

Conclusions: We found substantial variations in patient outcomes after OHCA within a large group of hospitals in Japan, despite adjustment for patient factors that are known to be associated with different outcomes.

Keywords: cardiac arrest; cardiac epidemiology; quality in health care.

Figure 1

Flow diagram for patient selection. OHCA, out-of-hospital cardiac arrest; EMS, emergency medical service; JAAM, Japan Association for Acute Medicine; ROSC, return of spontaneous circulation.

Figure 2

Caterpillar plot for adjusted rate of 1-month survival (A) and favourable functional outcome (B) among OHCA patients within each hospital. Adjusted for age, sex, cause of arrest (cardiac or non-cardiac), initial rhythm (VF/VT or PEA/asystole), witnessed collapse (none, a bystander or EMS personnel), bystander CPR (presence or absence), dispatcher CPR instruction (presence or absence), shock delivery with public AED (presence or absence), prehospital defibrillation (presence or absence), prehospital advanced airway placement with tracheal intubation or supraglottic airway device (yes or no), prehospital epinephrine administration (presence or absence), the interval from the first telephone call to CPR initiation by EMS providers and that from CPR initiation by EMS providers to hospital arrival. AED, automated external defibrillator; CPR, cardiopulmonary resuscitation; EMS, emergency medical service; OHCA, out-of-hospital cardiac arrest; PEA, pulseless electrical activity; VF, ventricular fibrillation, VT, ventricular tachycardia.