Association between hospital-acquired pneumonia and proton pump inhibitor prophylaxis in patients treated with glucocorticoids: a retrospective cohort study based on 307,622 admissions in China

BACKGROUND: Prophylaxis with proton pump inhibitor (PPI) in patients treated with glucocorticoid therapy is a common phenomenon in the general wards of Chinese hospitals. Many of these prescriptions are inappropriate and lead to overuse. Hospital-acquired pneumonia (HAP) is a possible adverse effect for this combination but remains controversial. METHODS: We designed a retrospective cohort study using electronic medical record databases from multiple hospitals to investigate whether PPI prophylaxis increases the risk of HAP in hospitalized patients receiving glucocorticoid therapy. The study population was adult patients who were not critical and treated with at least 1 dose of glucocorticoid during hospitalization and the exposure factor was PPIs prophylaxis. The odds ratio of HAP between the exposed and unexposed groups was calculated based on the cohort which was established by propensity score matching. The dose-effect relationship between PPI prophylaxis and HAP was also evaluated. RESULTS: Among the 307,622 admissions eligible for the study, a total of 217,460 (70.7%) admissions had a record of PPI prophylaxis. After reconstructed the cohort by propensity score matching, the exposed and unexposed groups both included 83,786 admissions. The incidence of HAP in the exposed group was higher than that in the unexposed group (2.1% vs. 1.5%, OR: 1.4, 95% CI: 1.3 to 1.5). The risk of HAP increased when the cumulative dose of PPI during hospital was more than 2 defined drug doses. Compared to the unexposed group, the adjusted odds ratio was 1.3 (95% CI: 1.2 to 1.4) in the medium-dose group (2–7 defined drug doses) and 1.9 (95% CI: 1.8 to 2.1) in the high-dose group (>7 defined drug doses). CONCLUSIONS: PPI prophylaxis increased the risk of HAP in hospitalized patients treated with glucocorticoid therapy and the risk of HAP increased as the dose of PPIs accumulated.