The prevalence of medication-related hospital readmissions after bariatric surgery: a retrospective observational study.

Introduction: Bariatric surgery may induce changes in the effects of oral medication, which may result in medication related problems. Therefore, tailored pharmacotherapy is necessary for individual patients following surgery. In case pharmacotherapy is not adjusted, adverse drug events and even unplanned hospital readmissions may occur. The prevalence of these medication-related readmissions is not known.

Aim: The primary objective of this study was to determine the prevalence of medication-related readmissions within two years after bariatric surgery. Secondary objectives were to determine the percentage of potentially preventable medication-related readmissions. The reasons for readmission, the associated medication, and medication errors involved in the potentially preventable readmissions were also determined.

Method: A retrospective, observational study in a large Dutch teaching hospital was performed. Unplanned readmissions of patients who underwent primary bariatric surgery between January 1, 2018 and August 31, 2020 were included with a follow-up of two years. Records were screened to identify potential medication-related reasons for readmissions. Identified records were independently assessed using adjusted versions of the algorithms of Kramer, Schumock & Thornton for causality and preventability by a doctor and pharmacist. All readmissions assessed as possibly (Kamer scores 0 through 3) or probably (Kramer score 4) related to medication were included. In addition, reasons for readmission, associated medication and medication errors were recorded. Descriptive statistics were used to analyze the data.

Results: In total, 606 unplanned readmissions of 356 individual patients were included. Eighty-three of 606 (13.7%, 95% CI 11.1-16.7%) readmissions were identified as medication-related with a median time between index hospitalization and readmission of 152 days (IQR 16-438). Of these readmissions 36 (43.3%) from 32 unique patients were potentially preventable. The most frequently occurring reasons for readmissions were abdominal pain and infections. Medication most frequently associated with readmissions were Proton Pump Inhibitors, opioids and antibiotics. Medication errors involved in the preventable readmissions were most often prescribing errors followed by non-adherence.

Conclusion: Medication-related readmissions frequently occur after bariatric surgery. More attention is needed for correct pharmacotherapy and patient education in this population.