Increased Out-of-Hospital Cardiac Arrest Risk in Cancer

BACKGROUND: Although cancer patients face an increased risk of cardiovascular disease, their risk of out-of-hospital cardiac arrest (OHCA) remains poorly characterized. OBJECTIVES: The objective of the study was to investigate the hazard of OHCA among patients with cancer and identify clinical factors associated with increased hazard compared with cancer-free controls. METHODS: This population-based, matched cohort study included adults (≥18 years) diagnosed with cancer from 2010 to 2022, matched 1:5 on age, sex, and region, to cancer-free controls. Using 7 national registers, we assessed the hazard of OHCA for all cancers combined and across subgroups, including cancer site, metastasis status, and cardiovascular risk factors, using Cox proportional hazards models and model-based estimates of cumulative incidence. RESULTS: A total of nearly 800,000 patients with cancer and 3,700,000 controls were included. Cancer was associated with a 55% higher hazard of OHCA (adjusted HR: 1.55; 95% CI: 1.50-1.60), than controls. The greatest excess hazards were observed in lung, gastrointestinal, and neurological cancers. The association was strongest within the first year after cancer diagnosis, but remained increased throughout follow-up. Lung and neurological cancers were associated with the greatest short-term hazards, approximately 6-fold higher than controls, whereas lung cancer and multiple myeloma showed the highest long-term excess hazards, approximately 2- to 3-fold higher. CONCLUSIONS: Patients with cancer had a higher hazard of OHCA than cancer-free controls. Cancer site, time since diagnosis, and metastasis status were key factors associated with the hazard of OHCA. These findings may help inform tailored cardiovascular risk assessment, preventive strategies, shared decision-making, and end-of-life planning in oncology care.