Economic evaluation of tramadol/paracetamol combination tablets for osteoarthritis pain in the Netherlands.

OBJECTIVE: To compare the costs of treating osteoarthritis (OA) pain using combination tramadol/paracetamol tablets, NSAIDs alone, NSAIDs plus proton pump inhibitors (PPIs), or NSAIDs plus histamine H(2)-receptor antagonists (H(2)RAs) from the perspective of the Dutch healthcare system. DESIGN AND METHODS: A decision-analytical model was constructed to model the cost outcomes of the four treatment strategies over 6 months. A cost-minimisation approach was used, which considered data related to resource utilisation, medication costs and costs for the treatment of adverse events. Data, derived mainly from the clinical literature, were supplemented by inputs from a Delphi panel as well as official price and tariff lists. The base-case analysis considered direct medical costs, including those for treating all adverse events with tramadol/paracetamol and gastrointestinal (GI) adverse events with NSAIDs. Separate scenario analyses explored costs of NSAID-based regimens: (i) according to 21 levels of risk for GI adverse events, and (ii) when renal events attributable to NSAIDs were considered. Robustness of the model was tested using univariate sensitivity analysis.
RESULTS: In the base-case analysis, costs for 6 months' treatment of OA pain using tramadol/paracetamol were euro244.45, compared with euro317.32 for NSAIDs + PPIs, euro200.67 for NSAIDs + H(2)RAs, and euro125.86 for NSAIDs alone. This provided a cost saving of euro72.87 per patient over 6 months for tramadol/paracetamol compared with NSAIDs + PPIs. Tramadol/paracetamol became cost saving compared with NSAIDs alone and NSAIDs + H(2)RAs for GI risk levels >13 and >10, respectively. When renal adverse events of NSAIDs were con- sidered, tramadol/paracetamol was cost saving compared with all NSAID-based regimens (saving euro228.40 vs NSAIDs, euro418.42 vs NSAIDs + PPIs, and euro302.69 vs NSAIDs + H(2)RAs [year of costing 2005]). Sensitivity analysis confirmed the model was robust to wide-ranging changes in the value of input parameters.
CONCLUSION: Tramadol/paracetamol is cost saving compared with NSAIDs + PPIs for the treatment of OA pain over a period of 6 months regardless of the risk of GI or renal complications. Tramadol/paracetamol is also cost saving compared with treatment with NSAIDs alone and NSAIDs + H(2)RAs for patients at medium and high risk of GI adverse events and in all cases if considering renal adverse events. Despite not being quantified in monetary terms, the lower incidence of adverse events with tramadol/paracetamol is a clinical benefit.