Protocol for an economic analysis of the randomised controlled trial of improving the wellbeing of people with opioid treated chronic pain : I-WOTCH study

Introduction: Over the last two decades, the use of opioids for the treatment of chronic pain in England has steadily increased despite lack of evidence of both long term effectiveness in pain relief and significant, well documented physical and mental adverse events. Guidelines recommend tapering when harms outweigh benefits, but the addictive nature of opioids hinders simple dose reduction strategies. Improving the Wellbeing of people with Opioid Treated CHronic pain (I WOTCH) trial tests a multicomponent self-management intervention aimed to help patients with chronic non malignant pain taper opioid doses. This paper outlines the methods to be used for the economic analysis of the I WOTCH intervention compared to the best usual care. Methods and analysis: Economic evaluation alongside the I WOTCH study, prospectively designed to identify, measure, and value key healthcare resource use and outcomes arising from the treatment strategies being compared. A within trial cost consequences analysis and a model based long-term cost effectiveness analysis will be conducted from the National Health Service and Personal Social Service perspective in England. The former will quantify key parameters to populate a Markov model designed to estimate the long-term cost and quality adjusted life years of the I-WOTCH programme against best usual care. Regression equations will be used to estimate parameters such as transition probabilities, utilities, and costs associated with the model’s states and events. Probabilistic sensitivity analysis will be used to assess the impact of parameter uncertainty onto the predicted costs and health outcomes, and the resulting value for money assessment of the I-WOTCH programme. Ethics and dissemination: Full ethics approval was granted by Yorkshire & The Humber – South Yorkshire Research Ethics Committee on September 13th, 2016 (16/YH/0325). Current protocol: version 1.7, date 31 July 2019. Findings will be disseminated in peer reviewed journals, scientific conferences, newsletters, and websites. Registration details: International Standard Randomised Controlled Trial Number: 49470934 (6 Feb 2017).