Geographical Association Between Basic Life Support Courses and Bystander Cardiopulmonary Resuscitation and Survival from OHCA in Denmark

Theo Walther Jensen,1– 3 Annette Kjær Ersbøll,3,4 Fredrik Folke,2,3,5 Mikkel Porsborg Andersen,6 Stig Nikolaj Blomberg,1– 3 Mathias Geldermann Holgersen,2,7 Lars Bredevang Andersen,1 Freddy Lippert,2,3 Christian Torp-Pedersen,6,8 Helle Collatz Christensen1,2,9 1Emergency Medical Services Region Zealand, Naestved, Denmark; 2Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; 3Copenhagen Emergency Medical Services, University of Copenhagen, Copenhagen, Denmark; 4National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark; 5Department of Cardiology, Herlev Gentofte University Hospital, Gentofte, Denmark; 6Department of Cardiology, Nordsjaellands Hospital, Hilleroed, Denmark; 7Paediatric Pulmonary Service, Department of Paediatrics and Adolescent Medicine, Copenhagen University Hospital, Copenhagen, Denmark; 8Aalborg University Hospital, Aalborg & Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; 9Danish Clinical Quality Program (RKKP), National Clinical Registries & Department of Clinical Medicine, Copenhagen, DenmarkCorrespondence: Theo Walther Jensen, Emergency Medical Services, Region Zealand and University of Copenhagen, Ringstedgade 61, 13. etage, Naestved, 4700, Denmark, Tel +45 51 21 10 06, Email theje@regionsjaelland.dkIntroduction: Annually, approximately 4% of the entire adult population of Denmark participate in certified basic life support (BLS) courses. It is still unknown whether increases in BLS course participation in a geographical area increase bystander cardiopulmonary resuscitation (CPR) or survival from out-of-hospital cardiac arrest (OHCA). The aim of the study was to examine the geographical association between BLS course participation, bystander CPR, and 30-day survival from OHCA.Methods: This nationwide register-based cohort study includes all OHCAs from the Danish Cardiac Arrest Register. Data concerning BLS course participation were supplied by the major Danish BLS course providers. A total of 704,234 individuals with BLS course certificates and 15,097 OHCA were included from the period 2016– 2019. Associations were examined using logistic regression and Bayesian conditional autoregressive analyses conducted at municipality level.Results: A 5% increase in BLS course certificates at municipality level was significantly associated with an increased likelihood of bystander CPR prior to ambulance arrival with an adjusted odds ratio (OR) of 1.34 (credible intervals: 1.02;1.76). The same trends were observed for OHCAs in out-of-office hours (4pm-08am) with a significant OR of 1.43 (credible intervals: 1.09;1.89). Local clusters with low rate of BLS course participation and bystander CPR were identified.Conclusion: This study found a positive effect of mass education in BLS on bystander CPR rates. Even a 5% increase in BLS course participation at municipal level significantly increased the likelihood of bystander CPR. The effect was even more profound in out-of-office hours with an increase in bystander CPR rate at OHCA.Keywords: basic life support, survival, geography, epidemiology, conditional autoregressive regression