Increased 5-year risk of stroke, atrial fibrillation, acute coronary syndrome and heart failure in out-of-hospital cardiac arrest survivors relative to population controls: a nationwide register-based

Background Out-of-hospital cardiac arrest (OHCA) survivors are a selected group of patients with younger age and less comorbid conditions relative to non-survivors. Long-term risk of stroke, atrial fibrillation or flutter (AF), acute coronary syndrome (ACS) and heart failure (HF) in OHCA survivors not diagnosed with any of these conditions as part of the cardiac arrest is unknown. Purpose To examine 5-year risk of stroke, AF, ACS and HF in 30-day OHCA survivors relative to age- and sex-matched population controls. Methods OHCA 30-day survivors and age- and sex-matched population controls not previously diagnosed with stroke, AF, ACS or HF or during the first 30 days after cardiac arrest were included using Danish Cardiac Arrest Registry data from 2001–2015 as well as the Danish Civil Registration System. Characteristics are compared using totals and percentages for categorical data and median and 25–75% percentiles for continuous data. Five-year outcomes are compared using cumulative incidence plots as well as Shared Frailty Cox regression modeling, unadjusted and adjusted for potential confounders including age, sex, hypertension, diabetes, chronic obstructive pulmonary disease (COPD), peripheral arterial disease (PAD), chronic ischemic heart disease (IHD), transient ischemic attack (TIA), thyroid disease, cholesterol-lowering, antiplatelet and anticoagulant agents. Results Of 4362 30-day survivors, 1063 were stroke-, AF-, ACS- and HF-naïve and 1051 were matched to population controls using age, sex and time of OHCA event as matching variables. The figure depicts the risk of stroke beyond day 30 to 5 years of follow-up was 4.7% versus 1.7% for OHCA survivors vs. controls. Risks of AF, ACS and HF were 7.0% vs. 2.1%, 4.7% versus 1.2% and 12.2% vs. 1.0%, respectively. OHCA 30-day survivors were significantly more likely to have PAD relative to controls, 4.9% vs. 1.1%. Differences in IHD (22.0% vs. 1.7%), hypertension (28.1% vs. 14.6%), diabetes (9.5% vs. 4.1%), lipid-lowering agents (27.6% vs. 9.5%), COPD (11.3% vs. 2.2%) were also significant. When adjusting for these comorbidities as well as for thyroid diseases, chronic kidney disease, cancer, antiplatelet and anticoagulant therapy, differences remained highly significant: HR stroke 3.33 [95% CI 2.21–5.02], HR AF 3.26 [2.28–4.66], HR ACS 3.36 [2.14–5.27] and HR HF 11.50 [8.02–16.48]. Conclusion We demonstrate an increased five-year risk of stroke, atrial fibrillation or flutter, acute coronary syndrome and heart failure in out-of-hospital cardiac arrest survivors without prior existence of any of these conditions. These results indicate that OHCA survivors continue to remain high-risk patients for cardiovascular events and prevention intervention is warranted. Funding Acknowledgement Type of funding source: None