The incidence and outcomes of out-of-hospital cardiac arrest precipitated by drug overdose: A systematic review and meta-analysis

Background: Out-of-hospital cardiac arrests (OHCA) precipitated by drug overdose (OD) are becoming an increasing public health problem in developed countries. Empirical data on the global incidence and outcomes are needed to guide preventive and treatment strategies. Methods: We conducted a systematic review using MEDLINE, Embase, Emcare, All EBM Reviews and CINAHL to identify observational or interventional studies reporting the incidence or outcomes of adult OHCA precipitated by drug OD between 1990 and 2018. Pooled incidence rates per 100,000 person-years and survival outcomes were summarised using random-effects models. Results: Twelve articles met the eligibility criteria, of which six were from North America, four from Europe and two from Asia. Only two studies reported the incidence of EMS-attended cases. The pooled incidence of EMS-treated OHCA was 1.4 cases per 100,000 person-years. The pooled rate of survival to hospital discharge and survival with favourable neurological outcome was 9% (95% CI: 6%, 12%; I² = 90%; p < 0.001) and 6% (95% CI: 2%, 13%; I² = 81%; p < 0.001), respectively. The pooled rate of return of spontaneous circulation was 25% (95% CI: 11%, 41%; I² = 97%; p < 0.001). Drug OD OHCA was associated with an improvement in the odds of survival to hospital discharge (pooled odds ratio 2.2, 95% CI: 1.7, 2.7; I² = 0%; p = 0.45). Conclusion: The incidence and survival outcomes of drug OD OHCA varies substantially across regions. Effective strategies designed to reduce incidence and improve survival outcomes are needed.