Cost-effectiveness analysis of a placebo controlled randomised surgical trial evaluating the effectiveness of arthroscopic subacromial decompression in patients with subacromial shoulder pain (CSAW)

Journal article

Aims The aims of this study were to compare the use of resources, costs and quality of life outcomes associated with subacromial decompression, arthroscopy only (placebo surgery) and no treatment for subacromial pain in the United Kingdom National Health Service, and to estimate their cost-effectiveness. Patients and Methods The use of resources, costs and quality-adjusted life years (QALYs) were assessed in the trial at six months and one year. Results were extrapolated to two years after randomisation. Differences between treatment arms, based on the intention-to-treat principle, were adjusted for covariates; missing data were handled using multiple imputation. Incremental cost-effectiveness ratios were calculated, with uncertainty around the values estimated using bootstrapping. Results Cumulative mean QALYs /mean costs of health care service use and surgery per patient from baseline to 12 months were estimated as 0.640 (standard error (SE) 0.024)/ £,3147 (SE 166) in the decompression arm, 0.656 (SE 0.020)/ £2830 (SE 183) in the arthroscopy only arm and 0.522 (SE 0.029)/ £1,451 (SE 151) in the no treatment arm. Statistically significant differences in cumulative QALYs and costs were found at six and 12 months for the decompression vs. no treatment comparison only. The probabilities of decompression being cost-effective compared with no treatment at a willingness-to-pay threshold of £20,000 per QALY were close to 0% at six months and approximately 50% at one year, with this probability potentially increasing for the extrapolation to two years. Discussion The evidence for cost-effectiveness at 12 months was inconclusive. Decompression may be cost-effective in the longer-term, but results of this analysis are sensitive to the assumptions made about how costs and QALYs are extrapolated beyond the follow-up of the trial.

Authors: Rombach, I; Merritt, N; Shirkey, B; Rees, J; Cook, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: British Editorial Society of Bone and Joint Surgery
• Journal: Bone and Joint Journal
• Volume: 101
• Issue: 1
• Publication date: 2019-01-02
• Acceptance date: 2018-10-17
• DOI: 10.1302/0301-620X.101B1.BJJ-2018-0555.R1
• EISSN: 2049-4408
• ISSN: 2049-4394
• Keywords: subacromial decompression; health economics; shoulder impingement; placebo surgery; cost-effectiveness analysis; quality adjusted life years