Proton pump inhibitor use and the risk of metachronous gastric cancer after H. pylori eradication in patients who underwent endoscopic resection for gastric neoplasms: A population‐based cohort study

Summary Background The association between proton pump inhibitors (PPI) use and gastric cancer remains controversial. Aims To investigate the impact of long‐term PPI use on metachronous gastric cancer after Helicobacter pylori eradication in high‐risk patients who underwent endoscopic resection of gastric neoplasms. Methods Using the Korean National Health Insurance Services database, we identified 1836 PPI users and 12,218 non‐users among patients who received H. pylori eradication therapy after endoscopic resection for gastric neoplasms between 2009 and 2014. We then compared the incidence of metachronous gastric cancer between the PPI user and non‐user groups. We conducted sensitivity analysis using various time lags and propensity score‐matched analysis to ensure the robustness of the results. Results After a median follow‐up of 7.3 years, the incidence of metachronous gastric cancer was significantly higher in the PPI user group than in the non‐user group, with a crude hazard ratio of 6.20 (95% confidence interval, 5.78–6.65). After adjustment, PPI use was associated with the development of metachronous gastric cancer, with an adjusted hazard ratio of 5.51 (95% confidence interval, 5.12–5.92). The PPI user group was categorised into three subgroups according to the cumulative PPI dose; the increased risk of metachronous gastric cancer remained significant regardless of the PPI dose. Moreover, these results remained robust after applying various time lags and propensity score‐matched analyses. Conclusions Long‐term PPI use is associated with an increased risk of metachronous gastric cancer in patients who undergo H. pylori eradication therapy after endoscopic resection of gastric neoplasms.