Key result
COX-2 inhibitors were used by 16% of UK and 21% of US NSAID cohorts, with COX-2 users having more baseline GI and CV risk factors but shorter treatment durations than seen in clinical trials.
Why the study?
What are the real-world patterns of use of COX-2 inhibitors and NSAIDs in the UK and USA populations?
Cohort (n=2,019,315)
Yes
What are the real-world patterns of use of COX-2 inhibitors and NSAIDs in the UK and USA populations?
The typical real-world use of COX-2 inhibitors is for shorter durations and at lower doses than in clinical trials, which may explain discrepancies in observed cardiovascular toxicity between trials and observational studies.
Shorter real-world durations may reconcile trial-observational CV toxicity differences; confirms channelling but leaves generalizability open.
BACKGROUND: COX-2 and NSAIDS differ in their gastrointestinal (GI) and cardiovascular (CV) toxicity from pharmacological, clinical and epidemiologic point of views. OBJECTIVE: Describe the patterns of use of NSAIDS and COX-2 in The Health Improvement Network (THIN) database in UK and the PharMetrics database in USA. METHODS: We examined the experience of 10 distinct cohorts of new users of diclofenac, naproxen, ibuprofen, piroxicam, other NSAIDS, meloxicam, celecoxib, etoricoxib, rofecoxib and valdecoxib. The study period was 1 January 1995 through 2004 (31 March in UK and 28 February in USA). We collected information on covariates including history of upper GI disease, CV disease, hepatic disease, dosage, concomitant medication, and visits to a rheumatologist. RESULTS: We identified 486 076 unique patient-drug pairs in UK and 1 533 239 in USA. In UK population 78 201 (16%) were COX-2 users and in PharMetrics 324 206 (21%) were COX-2 users. Diclofenac and ibuprofen (NSAIDS), and celecoxib and rofecoxib (COX-2) were the agents prescribed most frequently. The duration of therapy was longer among celecoxib and rofecoxib users than among other users. More COX-2 users than NSAIDS users received concomitant gastroprotective agents (GPA), corticosteroids and anti-platelet therapy, and had a history of thromboembolic events and hypertension. PharMetrics patients were prescribed higher doses of NSAIDS and COX-2. The use of any single agent for more than 90 days was uncommon, but more frequent in PharMetrics. Switching was uncommon and was generally to a NSAID. DISCUSSION: Our results confirm some previous findings from other authors such as the presence of both GI and CV channelling to COX-2 agents but refute others, such as the frequency of drug switching between these agents. The typical use of COX-2 agents in practice is for shorter duration, and at lower doses, than was employed in randomized clinical trials. This difference may help clarify the apparent discrepancy with respect to CV toxicity between the results from clinical trials, which showed a higher CV risk with these drugs, and non-experimental epidemiologic studies, which showed lower or no increase in risk.
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Arellano et al. (2006) conducted a cohort in NSAID and COX-2 inhibitor users (n=2,019,315). COX-2 inhibitors vs. NSAIDs was evaluated on Patterns of use (duration, dose, concomitant medications, switching). COX-2 inhibitors were used by 16% of UK and 21% of US NSAID cohorts, with COX-2 users having more baseline GI and CV risk factors but shorter treatment durations than seen in clinical trials.
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