Abstract
BACKGROUND: Although numerous studies have investigated out-of-hospital cardiac arrest, few studies have been conducted on in-hospital cardiac arrest (IHCA). Knowledge of the nationwide epidemiology of IHCA in Japan, with its super-aging society, is important to understand the current situation of IHCA and to establish evidenced-based medicine in the future. The present study aimed to determine the incidence and outcomes of IHCA and their trends in Japan. METHODS: This observational cohort study was performed using a national administrative inpatient database for more than 1600 acute-care hospitals covering about 50% of all acute-care hospital beds in Japan from April 2011 to March 2018. We defined cardiac arrest patients who received cardiopulmonary resuscitation (chest compression) during hospitalization as IHCA. We excluded out-of-hospital cardiac arrest patients from the source population. The incidence of IHCA per 1000 hospital admissions and survival to discharge rate was reported with trend analyses by calendar year 2011-2017. RESULTS: Among 53,871,101 hospitalized patients without out-of-hospital cardiac arrest patients in 1626 hospitals, 2,136,038 (4.0%) had cardiac arrest. Of them, 274,664 (12.9%) received cardiopulmonary resuscitation at least once during hospitalization and were identified as IHCA, and 1,861,374 (87.1%) did not receive cardiopulmonary resuscitation. The incidence of IHCA per 1000 hospital admissions was 5.1, with a significant decreasing trend from 6.1 in 2011 to 4.6 in 2017 (P for trend = 0.033). Our estimated incidence can be translated to approximately 87,000 IHCA cases in Japan each year. The percentage of IHCA patients among cardiac arrest patients was 12.9%, with a significant decreasing trend from 14.0% in 2011 to 12.2% in 2017 (P for trend = 0.006). The overall rate of survival to discharge was 12.7%, with a significant increasing trend from 10.5% in 2011 to 14.0% in 2017 (P for trend < 0.001). CONCLUSIONS: We found substantial associations between mortality and loss of health and IHCA in Japan. The incidence of IHCA showed a decreasing trend over time, the percentage of treated cardiac arrest patients also had a decreasing trend, and the overall survival to discharge rate improved over time.