Fig. 1

Flow chart of the selection process. Flow chart describing the selection steps of the systematic review and meta-analysis of comparing the efficacy and safety of mesenchymal stem cells in patients with systemic sclerosis, showing the number of studies excluded at each step, as well as the reasons for exclusion. *PubMed (n = 100), Ovid (n = 98), Cochrane (n = 11), Web of Science (n = 194), Embase (n = 186), Wanfang Data (n = 23), and China National Knowledge Infrastructure (n = 61). Ultimately, a total of 673 were retrieved from the seven database, and 5 articles were obtained by manual retrieval. Of these 678 studies, nine articles were finally identified, including 7 quantitative studies