Factors of importance to 30-day survival after in-hospital cardiac arrest in Sweden – A population-based register study of more than 18,000 cases

Background and objective In-hospital cardiac arrest (IHCA) constitutes a major contributor to cardiovascular mortality. The aim of the present study was to investigate factors of importance to 30-day survival after IHCA in Sweden. Methods A retrospective register study based on the Swedish Register of Cardiopulmonary Resuscitation (SRCPR) 2006–2015. Sixty-six of 73 hospitals in Sweden participated. The inclusion criterion was a confirmed cardiac arrest in which resuscitation was attempted among patients aged >18 years. Results In all, 18,069 patients were included, 39% of whom were women. The median age was 75 years. Thirty-day survival was 28.3%, 93% with a CPC score of 1–2. One-year survival was 25.0%. Overall IHCA incidence in Sweden was 1.7 per 1000 hospital admissions. Several factors were found to be associated with 30-day survival in a multivariable analysis. They included cardiac arrest (CA) at working days during the daytime (08–20) compared with weekends and night-time (20–08) (OR 1.51 95% CI 1.39–1.64), monitored CA (OR 2.18 95% CI 1.99–2.38), witnessed CA (OR 2.87 95% CI 2.48–3.32) and if the first recorded rhythm was ventricular fibrillation/tachycardia, especially in combination with myocardial ischemia/infarction as the assumed aetiology of the CA (OR for interaction 4.40 95% CI 3.54–5.46). Conclusion 30-day survival after IHCA is associated with the time of the event, the aetiology of the CA and the degree of monitoring and this should influence decisions regarding the appropriate level of monitoring and care.