Effect and safety of mesenchymal stem cells for patients with COVID-19: Systematic review and meta-analysis with...

The objective of this study was to assess whether mesenchymal stem cells (MSCs) therapy could offer survival advantages for patients with novel coronavirus disease 2019 (COVID-19). An electronic search of PubMed, Embase, Cochrane Library, Web of Science, WanFang, and CNKI was performed from December 1, 2019 to December 25, 2022. The primary outcome was all-cause mortality. Trial sequential analysis (TSA) was conducted in this meta analysis. Besides, subgroup analysis and meta-regression was performed using a random-effects model to find the potential sources of heterogeneity. Seventeen randomized controlled trials (RCTs) involving a total of 1073 patients with COVID-19 were included in this study. Compared with the control group, patients in the MSCs groups were associated with significantly reduced all-cause mortality (MSCs 18.4% vs. control 25.5%; risk ratio [RR] 0.73; 95% confidence interval [CI] 0.59-0.90; p = 0.004; I² = 0%). For all secondary outcomes, there wasn't significant improvement in the experimental group versus the control group regarding symptom remission rate (53.2%, 201/378 vs. 46.5%, 164/353; RR 1.15; 95% CI 1.00-1.32; p = 0.05; I² = 43%), but the pooled analysis revealed significant differences between the groups in length of hospital stay (MD: -3.82, 95% CI: -5.87 to -1.77; p = 0.0003, I2 = 0%), requirement of invasive mechanical ventilation (RR 0.52; 95% CI 0.33-0.82; p = 0.005; I²  = 0%) and post-CRP level (MD: -31.61; 95% CI -46.74 to -16.49; p < 0.0001). Moreover, regarding the incidence of adverse events (AEs) (RR 0.73; 95% CI 0.35-1.52; p = 0.39; I² = 44%) and serious adverse events (sAEs) (RR 0.87; 95% CI 0.40-1.92; p = 0.73; I² = 39%), no significant differences were observed between MSCs and control groups. The TSA analysis showed that the result of all-cause mortality might be false-positive result. Based on the pooled results in this study, compared with standard treatment, MSCs therapy may reduce all-cause mortality of patients with COVID-19 with no increase risk of AEs and sAEs, but may not improve symptom remission rate. Further more high-quality and large-sample RCTs should be performed to confirm these findings.