Pre-hospital factors and survival after out-of-hospital cardiac arrest according to population density, a nationwide study
Sidsel Møller, Shahzleen Rajan, Steen Møller-Hansen, Kristian Kragholm, Kristian Bundgaard Ringgren, Fredrik Folke, Carolina Malta Hansen, Freddy Lippert, Lars Køber, Gunnar Gislason, Christian Torp‐Pedersen, Mads Wissenberg
Abstract
AIM: This study aimed to examine the impact of population density on bystander cardiopulmonary resuscitation (CPR) and survival after out-of-hospital cardiac arrest (OHCA). METHODS: ). The association between population density, bystander cardiopulmonary resuscitation (CPR) and survival was examined using logistic regression, adjusted for age, sex, comorbitidies and calendar-year. RESULTS: 18,248 OHCAs were identified. Patients in areas of high compared to low population density were older, more often female, had more comorbidities, more witnessed arrests (very high: 59.6% versus low: 55.0%), shorter response time (very high: 10 min versus low: 14 min), but less bystander CPR (very high: 34.3% versus low: 45.1%). Thirty-day survival was higher in areas of higher population density (very high: 10.2% vs. low 5.3%), also in best-cases of witnessed arrests with bystander CPR and response time <10 min (very high: 33.6% versus low: 13.8%). The same trends were found in adjusted analyses with lower odds for bystander CPR (odds ratio [OR] 0.55 95% confidence interval [CI] 0.46-0.66) and higher odds for 30-day survival (OR 2.78, 95%CI 1.95-3.96) in the highest population density areas compared to low. CONCLUSIONS: Having an OHCA in higher populated areas were found associated with less bystander CPR, but higher survival. Identification of area-related factors can help target future pre-hospital care.