Cost-utility analysis of multimodal occupational therapy in patients with thumb base osteoarthritis

Abstract

Purpose: Patient education, hand exercises, and use of assistive devices and orthoses are regarded as first-line treatment for patients with hand osteoarthritis (OA), however there is limited evidence for the cost-effectiveness of such treatment. The purpose of this study is to assess the cost-utility of a multimodal occupational therapy treatment delivered in the waiting period before surgical consultation in patients with thumb base OA compared to usual care. Methods: This study presents an economic evaluation assessing the difference in health care use and quality-of-life during a 24-month period in a Norwegian multicenter randomized controlled trial designed to assess if multimodal occupational therapy in the waiting period before surgical consultation is more cost-effective compared to usual care. The outcomes in this study was to measure the quality adjusted life years (QALYs) in both the intervention and control group. All patients referred to surgical consultation due to thumb base OA at three departments of rheumatology between 2013 and 2015 were eligible for inclusion. In total, 180 patients were included and randomized to a control group or a multimodal occupational therapy group (90 patients in each group). During the waiting period between referral and actual surgical consultation, the control group continued with usual care which was staying on the waiting list and receiving information on hand OA. The intervention group got information on hand OA, ergonomic principles and use of assistive devices, and they were instructed in home-based hand exercises and received a prefabricated day orthosis and a customized night orthosis. The intervention group was instructed to use the orthoses and assistive devices as much as possible and perform home exercises three times per week for 12 weeks. They returned for adjustment of the exercise program and orthoses after 14 days. The patients were assessed at baseline, before surgical consultation (after approximately 4 months) and after 18 and 24 months. The within-trial economic analysis reports the incremental cost-effectiveness ratio (ICER) reflecting the between-group difference in incremental cost per QALY over 24 months. ICER is defined as the ratio of the difference in costs to the difference in effectiveness between two strategies. A generic health-related quality of life questionnaire, the EuroQol 5 Dimension (EQ-5D-5L) was used to calculate the QALYs at baseline, 4, 18 and 24 months. Costs were collected from different sources, taking a health care perspective; The occupation therapist reported the number of consultations related to the intervention; surgical procedure and post-operative follow-up were collected from patients’ journals; and additional consumption of primary and specialist health care was self-reported by the patient. Sensitivity analyses were performed to assess the robustness of the reported Results. The results are presented in a cost-effectiveness plane using bootstrapping. Willingness-to-pay threshold is set to be € 27 500 linked to the severity of this condition. Results: The mean age of the included patients was 63 years (SD 7.6) and 142 (79%) were women. There was a total between-group difference in QALYs of 0.07 utilities after 24 months, in favour of the intervention group. Operations constituted the main costs with 22 operations in the intervention group compared to 33 in the control group. The between-group difference in costs due to health care consumption was estimated to € 500 in favour of the intervention group (Figure 1). Conclusions: The Results in this within-trial analysis indicate that multimodal occupational therapy in the waiting period before surgical consultation compared to usual care is a cost-effective alternative taking a health care perspective.