OBJECTIVES: Myasthenia Gravis (MG) is a rare autoimmune neuromuscular disease resulting in muscle weakness affecting vision, swallowing, speech, mobility, dexterity and respiratory function. This analysis compared utility values (based on the five-level version of EQ-5D (EQ-5D-5L) and on the Health Utility Index (HUI3)) of adult MG patients with utilities from the general population.

METHODS: The MyRealWorld-MG study is a digital, observational, multi-country study (US, UK, Canada, Italy, Germany, Spain, Japan) among adult MG patients. Patients entered personal and disease characteristics via a smartphone application, and filled in the EQ-5D-5L and the HUI3.

The POPUP observational study collected similar data and was conducted in the US, UK, Canada, Belgium, Italy, Germany, Netherlands and Spain. POPUP enrolled members of the general public and national samples were representative by age, gender, education and region. POPUP data were age-gender matched to the proportions observed in MyRealWorld-MG.

RESULTS:

POPUP enrolled 9,000 participants whereas MyRealWorld-MG enrolled 1,859 patients; 70% were female and 16.5% was 18-34 years, 44.5% was 35-54 years, 39% was >54 years old. Mean EQ-5D-5L utilities based on the UK (crosswalk) value set were 0.795 in POPUP versus 0.683 in MyRealWorld-MG, a utility decrement of 0.113. This difference is twice the minimally important differences (MID) of 0.05 for EQ-5D-5L. The decrement was similar when other value sets were applied: 0.137 (US), 0.103 (Spain), 0.096 (Italy), 0.081 (Canada), 0.076 (Germany). EQ-5D-5L utilities were associated with disease severity: 0.774, 0.563 and -0.060 for mild, moderate and severe MG, respectively (UK value set).

HUI3 utilities were 0.747 in POPUP compared to 0.483 in MyRealWorld-MG, a decrement of 0.264 (compared to the MID=0.032). HUI3 utilities were more sensitive as the disease impact on vision, speech and dexterity was additionaly included.

CONCLUSIONS: Adult MG patients experience numerically and meaningfully lower health utility values than an age-gender matched general population sample.