Manual therapy, exercise therapy, or both, in addition to usual care, for osteoarthritis of the hip or knee. 2: Economic evaluation alongside a randomized controlled trial

Objective: To evaluate the cost effectiveness of manual physiotherapy, exercise physiotherapy, and a combination of these therapies for patients with osteoarthritis of the hip or knee. Methods: 206 Adults who met the American College of Rheumatology criteria for hip or knee osteoarthritis were included in an economic evaluation from the perspectives of the New Zealand health system and society alongside a randomized controlled trial. Resource use was collected using the Osteoarthritis Costs and Consequences Questionnaire. Quality-adjusted life years (QALYs) were calculated using the Short Form 6D. Willingness-to-pay threshold values were based on one to three times New Zealand's gross domestic product (GDP) per capita of NZ$ 29,149 (in 2009). Results: All three treatment programmes resulted in incremental QALY gains relative to usual care. From the perspective of the New Zealand health system, exercise therapy was the only treatment to result in an incremental cost utility ratio under one time GDP per capita at NZ$ 26,400 (-$ 34,081 to $ 103,899). From the societal perspective manual therapy was cost saving relative to usual care for most scenarios studied. Exercise therapy resulted in incremental cost utility ratios regarded as cost effective but was not cost saving. For most scenarios combined therapy was not as cost effective as the two therapies alone. Conclusions: In this study, exercise therapy and manual therapy were more cost effective than usual care at policy relevant values of willingness-to-pay from both the perspective of the health system and society.Trial registration number Australian New Zealand Clinical Trials Registry ACTRN12608000130369.