Zinc supplementation and COVID-19 mortality: a meta-analysis

Abstract

Background and aims: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a pneumonia outbreak and was called 2019 novel coronavirus disease (COVID-19). COVID-19 emerged in December 2019 and now considered a pandemic. Zinc supplementation can reduce mortality in patients with severe pneumonia. This study aimed at meta-analysis of the results of related studies and evaluate the effect of zinc supplementation on COVID-19 mortality.

Methods: A systematic search has conducted for manuscripts through PUBMED/Medline and Google Scholar (Cochrane guideline has considered it as the gray literature) up to September 2021. This meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Guideline for evaluation of the effect zinc supplementation on COVID-19 mortality. Based on the heterogeneity a fixed-effect or random-effect model, the OR and 95% CI were used to assess the combined risk.

Results: After assessment, five studies with 1506 participants in case and control groups were included in meta-analysis. The OR for one study was not estimable, and the pool OR was estimated for other studies with 1398 participants. The meta-analysis showed that zinc supplementation in cases led to a significant lower risk of mortality when it was compared with the control group; pooled OR (95% CI) was 0.57 [0.43, 0.77] (P < 0.001).

Conclusion: This meta-analysis has suggested that zinc supplementation is associated with a lower mortality rate in COVID-19 patients. Zinc supplementation could be considered as a simple way and cost benefit approach for reduction of mortality in COVID-19 patients.

Keywords: COVID-19; Meta-analysis; Mortality; SARS-CoV-2; Zinc.

Fig. 1

Flowchart of literature search for meta-analysis

Fig. 2

Forest plot showing the effect of zinc on COVID-19 mortality. The OR for one study that was conducted by Thomas et al. [15] was not estimable. OR  odds ratio

Fig. 3

Risk of bias graph and summary: review authors’ judgements about each risk of bias item presented as percentages across eligible studies. Studies that have done by Yao et al. [16] and Carlucci et al. [13] have categorized as good studies about the risk of bias based on the modified Newcastle-Ottawa Scale by the authors’ judgement

Fig. 4

Funnel plot for publication bias