Long-term Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-analysis.

IMPORTANCE

Data on long-term survival beyond 12 months after out-of-hospital cardiac arrest (OHCA) of a presumed cardiac cause are scarce.

OBJECTIVE

To investigate the long-term survival of adult patients after surviving the initial hospital stay for an OHCA.

DATA SOURCES

A systematic search of the EMBASE and MEDLINE databases was performed from database inception to March 25, 2021.

STUDY SELECTION

Clinical studies reporting long-term survival after OHCA were selected based on predefined inclusion and exclusion criteria according to a preregistered study protocol.

DATA EXTRACTION AND SYNTHESIS

Patient data were reconstructed from Kaplan-Meier curves using an iterative algorithm and then pooled to generate survival curves. As a separate analysis, an aggregate data meta-analysis was performed.

MAIN OUTCOMES AND MEASURES

The primary outcome was long-term survival (>12 months) after OHCA for patients surviving to hospital discharge or 30 days after OHCA.

RESULTS

The search identified 15 347 reports, of which 21 studies (11 800 patients) were included in the Kaplan-Meier-based meta-analysis and 33 studies (16 933 patients) in an aggregate data meta-analysis. In the Kaplan-Meier-based analysis, the median survival time for patients surviving to hospital discharge was 5.0 years (IQR, 2.3-7.9 years). The estimated survival rates were 82.8% (95% CI, 81.9%-83.7%) at 3 years, 77.0% (95% CI, 75.9%-78.0%) at 5 years, 63.9% (95% CI, 62.3%-65.4%) at 10 years, and 57.5% (95% CI, 54.8%-60.1%) at 15 years. Compared with patients with a nonshockable initial rhythm, patients with a shockable rhythm had a lower risk of long-term mortality (hazard ratio, 0.30; 95% CI, 0.23-0.39; P < .001). Different analyses, including an aggregate data meta-analysis, confirmed these results.

CONCLUSIONS AND RELEVANCE

In this comprehensive systematic review and meta-analysis, long-term survival after 10 years in patients surviving the initial hospital stay after OHCA was between 62% and 64%. Additional research is needed to understand and improve the long-term survival in this vulnerable patient population.