Ngan N. Lam

Background: Kidney transplant recipients are commonly prescribed proton-pump inhibitors (PPIs), but due to concern for polypharmacy, chronic use should be limited. Objective: The objective was to describe PPI use in kidney transplant recipients beyond their first year of transplant to better inform and support deprescribing initiatives. Design: We conducted a retrospective, population-based cohort study using linked health care databases. Setting: This study was conducted in Alberta, Canada. Patients: We included all prevalent adult, kidney-only transplant recipients between April 2008 and December 2017 who received their transplant between May 2002 and December 2017. Measurements: The primary outcome was ongoing or new PPI use and patterns of use, including frequency and duration of therapy, and assessment of indication for PPI use. Methods: We ascertained baseline characteristics, covariate information, and outcome data from the Alberta Kidney Disease Network (AKDN). We compared recipients with evidence of a PPI prescription in the 3 months prior to study entry to those with a histamine-2-receptor antagonist (H2Ra) fill and those with neither. Results: We identified 1823 kidney transplant recipients, of whom 868 (48%) were on a PPI, 215 (12%) were on an H2Ra, and 740 (41%) were on neither at baseline. Over a median follow-up of 5.4 years (interquartile range [IQR] = 2.6-9.3), there were almost 45 000 unique PPI prescriptions dispensed, the majority (80%) of which were filled by initial PPI users. Recipients who were on a PPI at baseline would spend 91% (IQR = 70-98) of their graft survival time on a PPI in follow-up, and nephrologists were the main prescribers. We identified an indication for ongoing PPI use in 54% of recipients with the most common indication being concurrent antiplatelet use (26%). Limitations: Our kidney transplant recipients have access to universal health care coverage which may limit generalizability. We identified common gastrointestinal indications for PPI use but did not include rare conditions due to concerns about the validity of diagnostic codes. In addition, symptoms suggestive of reflux may not be well coded as the focus of follow-up visits is more likely to focus on kidney transplant. Conclusions: Many kidney transplant recipients are prescribed a PPI at, or beyond, the 1-year post-transplant date and are likely to stay on a PPI in follow-up. Almost half of the recipients in our study did not have an identifiable indication for ongoing PPI use. Nephrologists frequently prescribe PPIs to kidney transplant recipients and should be involved in deprescribing initiatives to reduce polypharmacy.