Supplementary Material for: Helicobacter pylori infection as predictor of treatment outcomes of gastric cancer: a systematic review and metanalysis

Background: Helicobacter pylori infection is strongly associated with gastric cancer. However, there is currently no consensus on the association between H. pylori and gastric cancer prognosis. Methods: A systematic search was conducted on studies in PubMed, EMBASE, and Web of Science up to March 10, 2022. The quality of all included studies was assessed using the Newcastle-Ottawa Scale. The hazard ratio (HR) and its 95% confidence interval (95%CI) were extracted to analyze the association between H. pylori infection and prognosis of gastric cancer. In addition, subgroup analysis and publication bias were performed. Results: A total of 21 studies were involved. The pooled HR was 0.67 (95%CI, 0.56-0.79) for overall survival (OS) in H. pylori-positive patients, with the control (HR=1) being the H. pylori-negative group. In the subgroup analysis, the pooled HR was 0.38 (95%CI, 0.24-0.59) for OS in H. pylori-positive patients who received surgery combined with chemotherapy. The pooled HR for disease-free survival was 0.74 (95%CI, 0.63-0.8), and 0.41 (95%CI, 0.26-0.65) in patients received surgery combined with chemotherapy. Conclusions: H. pylori-positive gastric cancer patients have a better overall prognosis than negative patients. Helicobacter pylori infection has improved the prognosis of patients undergoing surgery or chemotherapy, among which the improvement was most obvious in patients undergoing surgery combined with chemotherapy.