Proton pump inhibitors and risk of Clostridium difficile infection: a multi-country study using sequence symmetry analysis.

Objective: To determine the association between incident proton pump inhibitor (PPI) use and Clostridium difficile infections across multiple countries Method: National data covering the total population in Australia and Korea, the Canadian population over 65 years and a 3 million person random sample data set from Taiwan were assessed, as were data from a worker insurance population and a hospital inpatient/outpatient population in Japan. Sequence symmetry analysis was used to assess the association with oral vancomycin dispensing as the outcome of interest. Results: 54,957 patients were included. Positive associations were observed in Australia; adjusted sequence ratio (ASR) 2.48 (95% CI 1.90, 3.12), Korea ASR 2.15 (95% CI 2.11, 2.19), Canada ASR 1.45 (95% CI 1.16, 1.79), Japan hospital dataset ASR 3.21 (95% CI 2.12, 4.55) and Japan worker insurance dataset ASR 5.40 (95% CI 2.73, 8.75). The pooled result was ASR 2.40 (95% CI 1.88, 3.05) and 3.16 (95% CI 1.95, 5.10) when limited to Japan, Korean and Taiwan. Results did not vary by individual PPI. The temporal analysis showed effects within the first two weeks of PPI initiation. Conclusion: Our study confirms the association between PPI initiation and C. difficile infections across countries in the Asia-Pacific region.