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

Abstract

Background: Research showing an association between proton pump inhibitors (PPIs) and Clostridium difficile infections has largely been undertaken in Europe and North America. Clostridium difficile strains vary by region and may influence risk estimates across regions. Aim: 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 Asian countries. Results did not vary by individual PPI. The temporal analysis showed effects within the first two weeks of PPI initiation. Conclusion: When analysis was limited to the Asian countries, pooled risk estimates were higher than those which had been observed in European and North American populations. Research to identify reasons underpinning any risk difference in the Asian region is required.