Cost-effectiveness of steroid (methylprednisolone) injections versus anaesthetic alone for the treatment of Morton's neuroma: economic evaluation alongside a randomised controlled trial (MortISE trial).

BACKGROUND: Morton's neuroma is a common foot condition affecting health-related quality of life. Though its management frequently includes steroid injections, evidence of cost-effectiveness is sparse. So, we aimed to evaluate whether steroid injection is cost-effective in treating Morton's neuroma compared with anaesthetic injection alone. METHODS: We undertook incremental cost-effectiveness and cost-utility analyses from the perspective of the National Health Service, alongside a patient-blinded pragmatic randomised trial in hospital-based orthopaedic outpatient clinics in Edinburgh, UK. Of the original randomised sample of 131 participants with Morton's neuroma (including 67 controls), economic analysis focused on 109 (including 55 controls). Both groups received injections guided by ultrasound. We estimated the incremental cost per point improvement in the area under the curve of the Foot Health Thermometer (FHT-AUC) until three months after injection. We also conducted cost-utility analyses using European Quality of life-5 Dimensions-3 Levels (EQ-5D-3L), enhanced by the Foot Health Thermometer (FHT), to estimate utility and thus quality-adjusted life years (QALYs). RESULTS: The unit cost of an ultrasound-guided steroid injection was £149. Over the three months of follow-up, the mean cost of National Health Service resources was £280 for intervention participants and £202 for control participants - a difference of £79 [bootstrapped 95% confidence interval (CI): £18 to £152]. The corresponding estimated incremental cost-effectiveness ratio was £32 per point improvement in the FHT-AUC (bootstrapped 95% CI: £7 to £100). If decision makers value improvement of one point at £100 (the upper limit of this CI), there is 97.5% probability that steroid injection is cost-effective. As EQ-5D-3L seems unresponsive to changes in foot health, we based secondary cost-utility analysis on the FHT-enhanced EQ-5D. This estimated the corresponding incremental cost-effectiveness ratio as £6,400 per QALY. Over the recommended UK threshold, ranging from £20,000 to £30,000 per QALY, there is 80%-85% probability that steroid injection is cost-effective. CONCLUSIONS: Steroid injections are effective and cost-effective in relieving foot pain measured by the FHT for three months. However, cost-utility analysis was initially inconclusive because the EQ-5D-3L is less responsive than the FHT to changes in foot health. By using the FHT to enhance the EQ-5D, we inferred that injections yield good value in cost per QALY. TRIAL REGISTRATION: Current Controlled Trials ISRCTN13668166.