Aetiology of in-hospital cardiac arrest and long-term survival after the first 30 days: insights from the Swedish registry for cardiopulmonary resuscitation

AIM: To investigate whether the aetiology of in-hospital cardiac arrest (IHCA) is associated with long-term survival after 30-day survival. METHODS: A nationwide registry-based cohort study was conducted using the Swedish Registry for Cardiopulmonary Resuscitation. Adult IHCA patients in Sweden between 2018 and 2023 who survived ≥30 days were included. Aetiologies were merged into six categories (myocardial ischemia [reference], other cardiac, pulmonary, infectious, haemorrhagic and other non-cardiac). Cox (proportional hazards) regression models were used to estimate crude and multivariable adjusted (demographics, comorbidities, arrest characteristics) hazard ratios (HRs) with 95% CIs for all-cause mortality. RESULTS: Among 2692 30-day survivors (median age 71 years; 67% male), 886 deaths (33%) occurred over a median 3.7-year follow-up; overall one‑year survival was 86%. In the fully adjusted model, higher hazards of death were observed for infectious (HR 1.79, 95% CI 1.30-2.47), haemorrhagic (1.71, 1.20-2.43), and pulmonary aetiologies (1.61, 1.24-2.11), compared to myocardial ischemia. No difference was observed for cardiac and other non‑cardiac aetiologies. CONCLUSIONS: Aetiology of in-hospital cardiac arrest is independently associated with long‑term prognosis after 30‑day survival. Compared with myocardial ischemia, infectious, haemorrhagic and pulmonary causes are associated with higher long‑term mortality. These findings support aetiology‑informed follow‑up after IHCA.