Mesenchymal Stem Cells on Mortality in COVID-19 Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BackgroundThe Coronavirus disease-2019 (COVID-19) pandemic continues, and the death toll continues to surge. This meta-analysis aimed to determine the efficacy of mesenchymal stem cells (MSCs) on mortality in patients with COVID-19.MethodsA systematic search was made of PubMed, Embase, Cochrane Library, and clinicaltrials.gov, without language restrictions. Randomized controlled trials (RCTs) on treatment of COVID-19 with MSCs, compared with placebo or blank, were reviewed. Studies were pooled to risk ratios (RRs), with 95% confidence intervals (CIs).ResultsSeventeen RCTs (enrolling 1019 participants) met the inclusion criteria. MSCs showed significant effect on 28-day mortality (RR 0.76, 95% CI 0.62 to 0.93; P = 0.008). There was no statistically significant difference in 60-day mortality (RR 0.87, 95% CI 0.70 to 1.09; P = 0.22), and 90-day mortality (RR 0.91, 95% CI 0.72 to 1.15; P = 0.44) between the two groups.ConclusionsMSCs significantly reduced 28-day mortality in patients with COVID-19. The long-term effect of MSCs on mortality require further study.Graphical AbstractMSCs Significantly reduced 28-day mortality in hospitalized patients with COVID-19