Abstract
BACKGROUND: Past studies have reported regional differences in the prognosis of out-of-hospital cardiopulmonary arrest (OHCA) in Japan, but there is a lack of sufficient information to explain the changes in neurological prognosis over time. METHODS: Using the All-Japan Utstein Registry, a nationwide population-based OHCA database, we included non-traumatic OHCA patients resuscitated by emergency responders across all seven regions from January 1, 2011, to December 31, 2017. The primary endpoint was a favorable neurological outcome one month after cardiac arrest, compared among these seven regions. The secondary endpoint was one-month survival after OHCA. RESULTS: There were 880,043 OHCA patients, of whom 721,455 (82.0%) were included in the analysis. Overall, a total of 17,685 (2.45%) patients survived with favorable neurological outcomes. Unadjusted neurological favorable outcomes varied regionally, ranging from 1.64% to 3.37% (rate difference: 1.73%; 95%CI: 1.57-1.89%). The East and Northeast had a significantly lower rate compared to the Midwest region (unadjusted rate ratio: 0.73; 95%CI: 0.70-0.76; p<0.001, 0.63; 95%CI: 0.59-0.67; p<0.001, respectively). The significant difference remained after adjustment for patient factors and prehospital factors (adjusted rate ratio: 0.68; 95%CI: 0.64-0.72, p<0.01, 0.70; 95%CI: 0.67-0.73, p<0.01, respectively). The secondary outcome, survival at one month, also showed similar regional differences. CONCLUSION: In this post-hoc analysis, nationwide, population-based study in Japan, we found that regional differences in the neurologic prognosis of OHCA patients persist. The difference has narrowed from previous years, but the causes still need to be investigated and improved in the future.