Background: Proton pump inhibitors (PPIs) play a well-documented role as a gastroprotective agent among NSAID users at an increased risk of peptic ulcer and bleeding. Observational studies have, however, suggested that the clinical efficacy of PPI therapy may be reduced because of poor adherence.
Aim: To study the association between adherence to concomitant PPI in current NSAID users and the risk of peptic ulcer and bleeding.
Materials and methods: Case-control study linking nationwide data from the Swedish Patient Registry with the Swedish Drug Prescription Database. The study population included patients admitted for a first-time peptic ulcer or bleeding and who were incident users of NSAID. Each case was matched on age, sex, NSAID duration, and calendar month with five controls. PPI adherence was calculated as the proportion of NSAID days being covered by PPI therapy. Matched and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using conditional logistic regression.
Results: A total of 3649 cases were identified. Patients with poor adherence (<20% PPI coverage) had a significantly increased risk of upper gastrointestinal complications (OR=1.88, 95% CI 1.22-2.88) compared with fully adherent patients (≥80% PPI coverage). As a continuous variable, the risk of an event increased with 6% points for every 10% decrease in PPI adherence (OR=1.06, 95% CI 1.03-1.10).
Conclusion: The gastroprotective effect of PPI in NSAID users is highly dependent on adherence, with about twice the risk in patients with poor adherence. Efforts to increase adherence should be an integrated part of clinical practice.