Impact on the Incremental Cost-Effectiveness Ratio of Using Alternatives to EQ-5D in a Markov Model for Multiple Sclerosis

OBJECTIVES This study responds to a request in the National Institute for Health and Care Excellence (NICE) guidance to assess the impact of using alternative sources of utility values, applied to multiple sclerosis (MS). METHODS Incremental cost-effectiveness ratios (ICERs) were calculated using utility values based on UK and Dutch values of EQ-5D, two UK mappings and one Dutch mapping of EQ-5D and two condition-specific instruments: the UK eight-dimensional Multiple Sclerosis Impact Scale (MSIS-8D) and the Dutch Multiple Sclerosis Impact Scale Preference-Based Measure (MSIS-PBM). Deterministic and Monte-Carlo simulation-based ICERs were estimated for glatiramer acetate versus symptom management using a lifetime Markov model. RESULTS For both UK and Dutch perspectives, mapped and condition-specific utility values expressed significantly higher quality of life for the worst health state of the model than did EQ-5D. The ICER of glatiramer acetate with EQ-5D was US$182,291 for The Netherlands and US$153,476 for the UK. Ratios for mapped and condition-specific utilities were between 20 and 60 % higher. CONCLUSION The overestimation of quality of life of patients with MS by mapped EQ-5D or condition-specific utility values, relative to observed EQ-5D, increases the ICER substantially in a lifetime Markov model.