Su1766 Gastroprotective Strategies in Chronic NSAID Users: A Cost-Effectiveness Analysis Comparing Single Tablet Formulations With Individual Components

Abstract

Background: Non-steroidal anti-inflammatory drugs (NSAID) are associated with gastrointestinal (GI) side effects. Co-therapy with gastroprotective agents (GPA) is therefore recommended in patients at high risk for GI complications. However, compliance with GPAs is low. Single tablet formulations combining GPA with NSAID may enhance compliance and reduce complications. Aim: To evaluate the cost-effectiveness of competing GPA strategies, including combination formulations, in the prevention of GI complications in chronic arthritis patients. Methods: We performed a cost-utility analysis to compare eight gastroprotective strategies including variations of NSAID, cyclooxygenase-2 inhibitors, proton pump inhibitor (PPI), histamine-2 receptor antagonists, misoprostol, and combination tablets. The time horizon was 5 years for a hypothetical 60-year old patient with chronic arthritis requiring long term NSAID-therapy. We derived estimates for outcomes and costs from the medical literature. The primary outcome was incremental cost per quality adjusted life year gained (ICER). Sensitivity analyses were performed to assess the effect of gastrointestinal complications, compliance rates, and drug costs on the outcomes. Results: For the average risk patient, NSAID+PPI co-therapy was a cost-saving and more effective strategy compared to NSAID monotherapy. With an ICER of €35,075 the NSAID/PPI single tablet formulation could only become “viable” (i.e. ICER < €20,000 per QALY gained) when the price decreased from €0,78 to €0,56 per tablet, or when PPI compliance fell below 51% in the NSAID+PPI strategy. All other strategies were more costly and less effective. The model was highly sensitive to the risk of GI complications, costs of PPI and NSAID/PPI single tablet formulation, and compliance. In patients with a 3-fold higher risk of GI complications, both NSAID+PPI co-therapy and the single tablet formulation were cost-effective. With the latter yielding an ICER of €9917. When the costs of PPIs exceeded €0.42/day or compliance to PPIs fell below 33%, the single tablet formulation became a dominant strategy (i.e. more effective and less costly than NSAID+PPI co-therapy). Conclusions: NSAID+PPI co-therapy is a cost-effective and cost-saving strategy in chronic arthritis patients at average risk for GI complications due to NSAID use. The NSAID/PPI single tablet formulation was only cost-effective in highrisk patients. Compliance to PPI was found to be an important and influential factor determining cost-effectiveness for both average and high risk patients.