Decreasing rates of gastroprotective agent (GPA) adherence among users of cyclooxygenase-2 (COX-2) inhibitors is linked to an increased risk of upper GI complications, according to a recent study. Current clinical guidelines recommend that GPAs, such as proton pump inhibitors and misoprostol(Drug information on misoprostol), be prescribed for patients who are receiving NSAIDs and COX-2 inhibitors and are at high risk for upper GI events. Previous research showed that the protective effect of GPAs is diminished in NSAID users who do not adhere to the GPA regimen, but evidence about the effect of adherence to a GPA regimen with COX-2 inhibitor use is limited.
Valkhoff and colleagues at Erasmus University Medical Center in the Netherlands analyzed data from population-based primary care registries on 14,416 patients aged 50 years and older for whom COX-2 inhibitors and GPAs were prescribed. GPA adherence was calculated as the proportion of the COX-2 inhibitor treatment days covered by a GPA prescription. Cases were part of the COX-2 blocker plus GPA group who had an upper GI complication (GI bleeding or symptomatic ulcer). Most patients used COX-2 inhibitors for less than 30 days.
During the study, 74 patients had an upper GI event; the incidence rate was 11.9 per 1000 COX-2 inhibitor user-years. The risk of upper GI complication was higher in low GPA adherers (the GPA was taken, on average, 1 of 5 days of COX-2 blocker use or less) than in full adherers (the GPA was taken on 4 of 5 days of COX-2 inhibitor use or more). For every 10% decrease in GPA adherence, there was a 9% increase in the risk of GI complications.
The findings confirm that GPA adherence is beneficial in reducing the risk of upper GI complications from the use of COX-2 inhibitors and that nonadherence is a modifiable risk factor, the investigators noted. The study appeared in Arthritis & Rheumatism, an American College of Rheumatology publication.