Importance of adherence to gastroprotection during cyclooxygenase 2 inhibitor treatment

Evidence shows that suboptimal adherence to gastroprotective agents (GPAs) decreases the beneficial effects on the risk of upper gastrointestinal (GI) complications (UGIC) associated with the use of traditional non steroidal anti-inflammatory drugs (NSAIDs) [1]. There is less evidence about the role of GPA adherence for lowering the risk of UGIC in selective cyclooxygenase (COX)-2 inhibitors users. A recent nested case-control study by Valkhoff et al [2] aimed to determine the association between GPA adherence and upper GI (UGI) tract events (an UGIC or a symptomatic ulcer) among selective COX-2 inhibitors users. Authors obtained the data from three dynamic population-based primary care databases of UK, The Netherlands and Italy. Three kinds of exposure cohorts were created. The first was the total selective COX-2 treated cohort, which was split into the other 2 cohorts: selective COX-2 minus GPA-treated cohort and selective COX-2 plus GPA treated cohort. The case-control study nested within selective COX-2 inhibitors plus GPA treated cohort. Cases were patients who were newly starting treatment with selective COX-2 inhibitors plus GPA (at least 1 day of GPA exposure) and had a UGI tract event during the selective COX-2 inhibitor treatment or within a maximum of 60 days thereafter. Each case was matched with all eligible patients without UGI events in treatment with selective COX-2 inhibitors and GPA for age, sex, database