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.