Cost-utility analysis of risk-based stratified primary care for common musculoskeletal pain presentations: a cluster-randomised, controlled trial

Background Risk-based stratified care (SC) has demonstrated cost-effectiveness versus usual primary care for non-specific low back pain. The STarT MSK trial investigated the cost-effectiveness of risk-based stratified care versus non-stratified usual primary care for patients with the five most common musculoskeletal pain presentations. Methods A cost-utility analysis was undertaken over 6-months. The base-case analysis estimated the incremental costs per additional quality-adjusted life year (QALY), using the EQ-5D-5L to generate QALYs, for the overall trial population and for each risk subgroup (low, medium, high risk) for persistent disabling pain. The base-case analysis used the intention-to-treat principle and was performed from an NHS and personal social services (PSS) perspective. Uncertainty was explored with cost-effectiveness acceptability curves. Sensitivity analyses included a healthcare and societal perspective, complete-case, and risk subgroup analyses. Results Risk-based stratified primary care showed similar costs to usual primary care, with a small QALY gain of 0.0041 (95% CI -0.0013, 0.0094). The incremental cost-effectiveness ratio was £1,670 per QALY with a likelihood that stratified care represents cost-effective use of resources of 73% at a willingness-to-pay threshold of £20,000 per QALY. In subgroup analyses, stratified care was only likely to be cost-effective for the subgroup of patients at high risk of poor outcome. Conclusions Risk-based stratified primary care for patients with the five common musculoskeletal pain presentations resulted in similar costs and small QALY gains compared to usual, non-stratified primary care overall and therefore, showed inconclusive results overall. Trial Registration: ISRCTN Registry ISRCTN15366334; http://www.isrctn.com/ISRCTN15366334.