Abstract
INTRODUCTION: In a previously published randomised, placebo-controlled trial, 800 mg/day of pharmaceutical-grade chondroitin sulfate (CS) was shown to be superior to placebo in reducing pain and improving function over 6 months in patients with symptomatic knee osteoarthritis (OA). The aim of the current post hoc analyses was to evaluate the cost-effectiveness of CS compared with placebo in a European perspective using individual patient data from this clinical trial. METHODS: Patients with knee OA randomised to CS or placebo were followed up at 1, 3 and 6 months. The algo-functional Lequesne index was used to derive the EuroQol Five-Dimension Five-Level (EQ-5D-5L) score based on a validated formula. The EQ-5D-5L scores at each time point were used to calculate the changes in quality-adjusted life years (QALYs) with the area under the curve method. Costs were assessed using the average price of CS in the countries where the original study took place and where CS is currently marketed. The costs of CS in three countries were then used (i.e. the Czech Republic, Italy and Switzerland). The incremental cost-effectiveness ratio (ICER) threshold for CS to be considered cost-effective was set at 91,870 EUR per QALY (equivalent to the usually recommended threshold of US $100,000). The study used an intention-to-treat population, i.e. patients who received one dose of the study drug, and imputed missing values using the basal observation carried forward method. RESULTS: No significant differences in baseline characteristics were observed between the CS group (N = 199) and the placebo group (N = 205). The mean cost of CS for 6 months of treatment was 194.74 EUR. After 6 months of treatment, CS showed a mean ICER of 33,462 (95% CI 5130-61,794) EUR per QALY gained, indicating cost-effectiveness compared with placebo. The acceptability curve for cost-effectiveness shows that the CS treatment is likely to be cost-effective compared with placebo, with a 93% probability when the ceiling ratio is set at 91,870 EUR per QALY gained. CONCLUSIONS: These results highlight the role of CS as a cost-effective therapeutic option in the management of OA. However, further studies taking into account the use of other healthcare resources are warranted for a more complete understanding.