EQ-5D-5L and SF-6D health utility index scores in patients with myasthenia gravis.

BACKGROUND AND PURPOSE: Health utilities are a preference-based method of valuing health states that are used in healthcare research, such as economic evaluations. There are limited health utility valuation data for patients with myasthenia gravis (MG). The aim of the study was to describe health utilities for patients with MG and different health states, using the EQ-5D-5L and SF-6D utility instruments, and to explore clinical and demographic determinants of utilities in this population.

METHODS: Patients completed the EQ-5D-5L and SF-6D. In addition, patients were assessed with the Myasthenia Gravis Foundation of America classification, Myasthenia Gravis Impairment Index and MG-QOL15 as disease-specific measures, and the Neuro-QoL Fatigue scale. We calculated mean utilities for each Myasthenia Gravis Foundation of America severity class. We built regression models for the EQ-5D-5L and SF-6D to determine the clinical and demographic factors that determine patients' valuation of their health state.

RESULTS: Among 254 patients, mean EQ-5D-5L health utilities were as follows: Remission, 0.94 ± 0.03; Minimal Manifestations, 0.92 ± 0.04; Class I, 0.89 ± 0.06; Class II, 0.78 ± 0.16; Class III, 0.58 ± 0.24 and Class IV, 0.61 ± 0.22. Mean SF-6D health utilities were as follows: Remission, 0.83 ± 0.07; Minimal Manifestations, 0.86 ± 0.14; Class I, 0.82 ± 0.14; Class II, 0.67 ± 0.12; Class III, 0.56 ± 0.11 and Class IV, 0.50 ± 0.10. The limb/axial scores were more highly correlated to health utilities than ocular or bulbar scores.

CONCLUSIONS: We present estimates of health utilities for patients with MG that can be used in cost-utility and decision analyses. Limb/axial symptoms had a higher impact on health utilities than ocular or bulbar symptoms, which might reflect the impact of mobility on health valuation.