Abstract 267: Differences Of Temporal Trends In Outcomes After Out-of-hospital Cardiac Arrest Between Urban And Rural Regions In Japan: A 4-year Observational Study From 2016 To 2019

Abstract

Introduction: Recently, multiple studies have demonstrated improvement in survival after out-of-hospital cardiac arrest (OHCA). However, outcomes after OHCA vary with region and city worldwide. Hypothesis: Differences of temporal trends in outcomes after OHCA between rural and urban regions in Japan were postulated. Methods: We included 98,496 patients (aged ≥18 years) using an All-Japan Utstein-style Registry who were witnessed by bystanders after OHCA of presumed cardiac origin between January 1, 2016 and December 31, 2019. Based on population density, patients were classified into urban (n=76,411, 28 prefectures with a population of ≥200 inhabitants/km 2 ) and rural (n=22,085, 19 prefectures with a population of <200 inhabitants/km 2 ) groups. The study endpoints were 1-month survival and neurologically intact survival, defined with a cerebral performance category (CPC) score of 1 or 2. Results: The mean age in rural regions significantly increased from 77.1 years to 77.8 years ( P <0.01) despite unchanged patients’ age in urban regions for 4 years ( P =0.45). The bystander cardiopulmonary resuscitation (B-CPR) rate in urban regions significantly increased from 54.0% to 55.7% ( P <0.01) unlike in rural regions ( P =0.45). The overall crude 1-month survival and CPC 1-2 rates during the study periods were 10.9% and 6.8%, respectively. The overall 1-month survival and CPC 1-2 rates significantly improved from 2016 to 2019; the corresponding risk-adjusted ratios per year were 1.04 [95% confidence interval (CI), 1.02-1.07, P <0.01] and 1.03 [1.01-1.06, P <0.05]. In the urban group, 1-month survival and CPC 1-2 rates significantly improved from 2016 to 2019; the corresponding risk-adjusted ratios per year were 1.05 [95% CI, 1.03-1.08, P <0.01] and 1.04 [1.01-1.07, P <0.01]. However, in the rural group, 1-month outcomes did not significantly improve from 2016 to 2019; the corresponding risk-adjusted ratios per year were 0.99 [95% CI, 0.95-1.04, P =0.68] and 1.01 [0.95-1.07, P =0.74]. Conclusions: One-month outcomes after OHCA significantly improved over the recent 4 years in urban regions, unlike in rural regions in Japan. No change in B-CPR rate in rural regions was noted, and an increase in the B-CPR rate in urban regions may be associated with these results.