The incidence and prevalence of proton pump inhibitor usage among internal medicine patients after hospital admission: A retrospective cohort study

Background The use of proton pump inhibitors (PPIs) has increased over the past decades. One potential gateway into new PPI use is following a hospital admission. The study aimed to examine the incidence of new PPI usage following admission to internal medicine services and the ratio of new persistent users. Methods A retrospective descriptive study was conducted among all adults who had been admitted to internal medicine wards at the National University Hospital of Iceland from 2010–2020. Data was obtained from the Icelandic Internal Medicine Database. The proportion of patients who started treatment with PPI within 3 months of discharge (new users) and the proportion of patients who continued to use it after 3 months (persistent users) were examined. Results Among 85.942 admissions during the study period, 7238 (15.6%) became new users, and of those 4942 (68%) were new persistent users. The incidence of new PPI use was highest for patients discharged from gastroenterology (32.2%), hematology (31.8%), and oncology (29.2%). Patients with new PPI use more commonly had a history of malignancy (19.5%) and liver disease (22.7%) and more commonly were admitted to the ICU during their hospitalization. The highest ratio of persistent usage was among patients discharged from geriatric medicine (84%). Conclusion One in every six patients admitted to internal medicine wards filled out a prescription for PPI within 3 months from discharge, and a large proportion of them became persistent users. The high rate of new PPI users from oncology and hematology is noteworthy and requires further research.