Health Economic Evaluation of a High and Low Molecular Weight Hyaluronic Acid Formulation for the Treatment of Knee Osteoarthritis. Post Hoc Analyses from a Randomized Clinical Trial

INTRODUCTION: In a recent randomized placebo-controlled trial, a single intra-articular injection of a high and low molecular weight hyaluronic acid formulation (HA–HL) was shown to be effective in providing a clinically meaningful reduction in pain and functional limitation up to 24 weeks in subjects with painful knee osteoarthritis (OA). The objective of this post hoc analyses is to assess the cost-effectiveness of HA–HL compared with placebo using individual patient data from this clinical trial in a Swiss health care perspective. METHODS: A total of 692 patients fulfilling the inclusion criteria were randomly allocated to HA–HL or placebo groups. Each patient received one intra-articular injection of HA–HL or placebo at baseline and was then followed-up for a total duration of 24 weeks with five follow-up visits (i.e., after weeks 1, 6, 12, 18, and 24). The EQ-5D-5L five-point verbal Likert scale was used to calculate the health utility and the related quality-adjusted life-years (QALYs) using the area-under-the-curve (AUC) method. For the costs, the price of HA-HL in Switzerland was used. The primary threshold for the incremental cost/effectiveness ratio (ICER) below which HA-HL was considered as cost-effective was 91,540 Swiss francs (CHF) per QALY (i.e., US $100,000). RESULTS: No significant difference between the baseline characteristics of the HA–HL group and the placebo group was observed. With a mean ICER of 27,212 CHF per QALY (95% CI 20,135–34,289), HA–HL was considered as cost-effective compared to placebo. Sensitivity analyses (e.g., using lower or upper limit prices or using other threshold values) gave similar results, i.e., ICERs far below the threshold values of cost-effectiveness. CONCLUSIONS: These results confirm the role of HA–HL as a cost-effective therapeutic option in the management of OA. However, more studies taking into account the utilization of other health care resources are needed.