Long-term outcomes after out-of-hospital cardiac arrest: A systematic review and meta-analysis

Aims Long term outcomes after out-of-hospital cardiac arrest (OHCA) are not well understood. This study aimed to evaluate the long-term (1-year and beyond) survival outcomes, including overall survival and survival with favorable neurological status and the quality-of-life (QOL) outcomes, among patients who survived the initial OHCA event (30 days or till hospital discharge). Methods Embase, Medline and PubMed were searched for primary studies (randomized controlled trials, cohort and cross-sectional studies) which reported the long-term survival outcomes of OHCA patients. Data abstraction and quality assessment was conducted, and survival at predetermined timepoints were assessed via single-arm meta-analyses of proportions, using generalized linear mixed models. Comparative meta-analyses were conducted using the Mantel-Haenszel Risk Ratio (RR) estimates, using the DerSimonian and Laird model. Results 67 studies were included, and among patients that survived to hospital discharge or 30-days, 77.3% (CI = 71.2–82.4), 69.6% (CI = 54.5–70.3), 62.7% (CI = 54.5–70.3), 46.5% (CI = 32.0–61.6), and 20.8% (CI = 7.8–44.9) survived to 1-, 3-, 5-, 10- and 15-years respectively. Compared to Asia, the probability of 1-year survival was greater in Europe (RR = 2.1, CI = 1.8–2.3), North America (RR = 2.0, CI = 1.7–2.2) and Oceania (RR = 1.9, CI = 1.6–2.1). Males had a higher 1-year survival (RR:1.41, CI = 1.25–1.59), and patients with initial shockable rhythm had improved 1-year (RR = 3.07, CI = 1.78–5.30) and 3-year survival (RR = 1.45, CI = 1.19–1.77). OHCA occurring in residential locations had worse 1-year survival (RR = 0.42, CI = 0.25–0.73). Conclusion Our study found that up to 20.8% of OHCA patients survived to 15-years, and survival was lower in Asia compared to the other regions. Further analysis on the differences in survival between the regions are needed to direct future long-term treatment of OHCA patients.