Have COX-2 inhibitors influenced the co-prescription of anti-ulcer drugs with NSAIDs?

Abstract

To quantify usage of COX-2 inhibitors compared with nonselective NSAIDs and to determine their impact (including financial) on the co-prescription of antipeptic ulcer (anti-PU) drugs. The Irish General Medical Services prescription database (covering 1.2 million people) was examined for NSAID prescriptions during December 1999-November 2001. NSAID users were excluded during the first 6 months. During the next 12 months (study period) patients on NSAIDs (>or= 3 prescriptions) were identified. The study period and final 6 months provided data on co-prescription of anti-PU drugs. Age, gender, number of concomitant prescriptions, co-prescribing of anti-PU drugs and monthly cost were evaluated for 8 NSAIDs (n= 4 non-selective NSAIDs and n= 4 COX-2 inhibitors) and odds ratios (OR) calculated using logistic regression. COX-2 inhibitors were prescribed more frequently in older, female patients and those receiving multiple medications. After adjustment for age, gender and polypharmacy, anti-PU drugs were prescribed more frequently with COX-2 inhibitors (OR = 1.31 (1.23,1.40)). COX-2 inhibitors were up to 10-fold more expensive, median monthly costs (including anti-PU drugs) ranging from Euros 34.61 (COX-2 inhibitors) to Euros 3.26 (nonselective NSAIDs). Since COX-2 inhibitors are associated with increased rates of co-prescription of anti-PU drugs and are more expensive than non-selective NSAIDs, these results suggest that the expected cost-savings with COX-2 inhibitors may not be occurring in practice.