Cost-effectiveness analysis
pain
SECONDARY, EMERGENCY, SENSITIVITY
The cost-effectiveness analysis was from an NHS secondary care perspective with a four-year time horizon. The groups were compared as randomised. Inpatient stays, outpatient visits (including physiotherapy and OT appointments), procedures and Emergency Department attendances clinically judged (by NH, blinded to treatment arm) to be related to the patient’s TKR or ongoing pain in their knee were included in the analysis. NHS reference costs for 2020–2021 were used to value the resource use data obtained 12 to 48 months after randomisation [Sensitivity analyses were used to address uncertainty. Different discount rates were used for costs and outcomes (1.5% and 5%). The base case analysis had used short stay (less than two days) costs and long stay costs (two days or more) to value the inpatient stays. This was altered to a value of an elective inpatient stay in the 2020-21 NHS reference costs. Finally, to explore assumptions in relation to missing data the following approach was taken. For each arm separately, a weighting factor was calculated by dividing the 12-month costs and utilities of those who did not complete the longer-term follow-up questionnaire with those who did. The weighted mean cost/utility was then used to impute missing longer-term follow-up cost and utility data.