Use and costs of anti-secretory and cardiovascular co-medication in osteoarthritis patients treated with selective or non-selective NSAIDS.

OBJECTIVE: This study aims to compare use and costs of anti-secretory and cardiovascular co-medication in osteoarthritis patients treated with selective or non-selective NSAIDs.
METHOD: A retrospective study examined Belgian patients aged 65 years or more who suffer from osteoarthritis and are chronic users of selective NSAIDs (n=1,376) or non-selective NSAIDs (n=8,482). A before-and-after analysis compared drug use and costs between period 1 (first 6 months of 2002) and period 2 (several 1-year periods stretching over 2003-2004). A cohort analysis contrasted patients taking selective NSAIDs with patients taking non-selective NSAIDs. MAIN OUTCOME MEASURES: Anti-secretory co-medication included histamine H2-receptor antagonists and proton pump inhibitors. Cardiovascular co-medication referred to cardiac glycosides, anti-arrhythmics, anti-thrombotics, anti-angina drugs, anti-hypertensive drugs and serum-lipid-reducing drugs. Volume of drug use was expressed as number of packages and costs were computed in Euro.
RESULTS: The volume of anti-secretory co-medication increased by 36% with selective NSAIDs and by 55% with non-selective NSAIDs between periods 1 and 2. Cardiovascular co-medication rose by 18% with selective NSAIDs and by 12% for non-selective NSAIDs. Focusing on patients who did not take anti-secretory co-medication in period 1, patients taking selective NSAIDs were just as likely to start anti-secretory co-medication in period 2 as patients taking non-selective NSAIDs (odds ratio: 1.05; 95% confidence interval: 0.90-1.23). Patients taking selective NSAIDs were just as likely to start cardiovascular co-medication as patients taking non-selective NSAIDs (odds ratio: 1.03; 95% confidence interval: 0.78-1.36). Annual costs of treating osteoarthritis in ambulatory care amounted to 756 <euro> with selective NSAIDs and 416 <euro> with non-selective NSAIDs. This originated from higher acquisition costs (278 <euro> vs. 24 <euro>) and higher costs of co-medication (477 <euro> vs. 392 <euro>) with selective NSAIDs.
CONCLUSIONS: The use of selective and non-selective NSAIDs is accompanied by a higher use of co-medication over time. The increase in anti-secretory co-medication was more prominent with non-selective NSAIDs. The rise in cardiovascular co-medication was more pronounced with selective NSAIDs. Treatment of osteoarthritis with selective NSAIDs is more expensive than with non-selective NSAIDs in terms of acquisition costs and costs of co-medication.