Impact of preoperative sarcopenia on postoperative complications and prognosis of gastric cancer resection: A meta-analysis of cohort studies

•Preoperative sarcopenia increases the risk of overall postoperative complications in patients of gastric cancer resection.•Preoperative sarcopenia reduced the overall survival rate of patients after gastric cancer resection.•For patients with gastric cancer, sarcopenia evaluation and active intervention should be performed early to reduce the risk of postoperative complications, improve poor prognosis, and improve the quality of life of patients. Background The effect of preoperative sarcopenia on postoperative complications and prognosis in patients undergoing gastrectomy for gastric cancer has been controversial. The purpose of this study was to explore the effect of preoperative sarcopenia on postoperative complications and prognosis of patients with gastric cancer through meta-analysis method, providing new ideas for the prognosis study of patients undergoing gastrectomy for gastric cancer. Methods From databases establishment to April 2021, we systematically searched PubMed, Embase, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP, WanFang Data, and Chinese Biomedical Literature Database (CBM) to collect cohort studies on the effect of sarcopenia on postoperative complications or prognosis of gastric cancer. Based on the inclusion and exclusion criteria, two researchers independently screened the literature and extracted the data. The Newcastle-Ottawa Scale was used to evaluate the quality of the included studies and Revman 5.3 software was used for the meta-analysis. Result A total of 20 studies (11 prospective cohort studies and 9 retrospective cohort studies) involving 7615 patients were finally included. Meta-analysis showed that: 1) preoperative sarcopenia significantly increased the risk of overall complications (risk ratio[RR] =2.89, 95% confidence interval[CI]: 1.86, 4.49; P