Global Excess Mortality during COVID-19 Pandemic: A Systematic Review and Meta-Analysis

BACKGROUND: Currently, reported COVID-19 deaths are inadequate to assess the impact of the pandemic on global excess mortality. All-cause excess mortality is a WHO-recommended index for assessing the death burden of COVID-19. However, the global excess mortality assessed by this index remains unclear. We aimed to assess the global excess mortality during the COVID-19 pandemic. METHODS: We searched PubMed, EMBASE, and Web of Science for studies published in English between 1 January 2020, and 21 May 2022. Cross-sectional and cohort studies that reported data about excess mortality during the pandemic were included. Two researchers independently searched the published studies, extracted data, and assessed quality. The Mantel-Haenszel random-effects method was adopted to estimate pooled risk difference (RD) and their 95% confidence intervals (CIs). RESULTS: A total of 79 countries from twenty studies were included. During the COVID-19 pandemic, of 2,228,109,318 individuals, 17,974,051 all-cause deaths were reported, and 15,498,145 deaths were expected. The pooled global excess mortality was 104.84 (95% CI 85.56-124.13) per 100,000. South America had the highest pooled excess mortality 134.02 (95% CI: 68.24-199.80) per 100,000, while Oceania had the lowest -32.15 (95% CI: -60.53--3.77) per 100,000. Developing countries had higher excess mortality 135.80 (95% CI: 107.83-163.76) per 100,000 than developed countries 68.08 (95% CI: 42.61-93.55) per 100,000. Lower middle-income countries 133.45 (95% CI: 75.10-191.81) per 100,000 and upper-middle-income countries 149.88 (110.35-189.38) per 100,000 had higher excess mortality than high-income countries 75.54 (95% CI: 53.44-97.64) per 100,000. Males had higher excess mortality 130.10 (95% CI: 94.15-166.05) per 100,000 than females 102.16 (95% CI: 85.76-118.56) per 100,000. The population aged ≥ 60 years had the highest excess mortality 781.74 (95% CI: 626.24-937.24) per 100,000. CONCLUSIONS: The pooled global excess mortality was 104.84 deaths per 100,000, and the number of reported all-cause deaths was higher than expected deaths during the global COVID-19 pandemic. In South America, developing and middle-income countries, male populations, and individuals aged ≥ 60 years had a heavier excess mortality burden.