The Impact of Myasthenia Gravis in the Real World

The EQ-5D-5L comprises two parts - the EQ-5D-5L descriptive system and the EQ Visual Analogue Scale (EQ VAS).

The descriptive system comprises 5 dimensions (mobility, self care, usual activities, pain/discomfort, and anxiety/depression), each with 5 levels (no problems, slight problems, moderate problems, severe problems, and extreme problems - i.e., higher scores represent worse health). The digits for 5 dimensions can be combined in a 5-digit number describing the respondent's health state.

The EQ VAS records the respondent's self-rated health on vertical, visual analogue scale with endpoints labelled 'the best health you can imagine' and 'the worst health you can imagine'. Higher scores represent better self-perceived health.

The MG-ADL is a myasthenia gravis-specific 8-item scale, which assesses the severity of the following symptoms: talking, chewing, swallowing, breathing, impairment of ability to brush teeth/comb hair, impairment of ability to rise from a chair, double vision, and eyelid droop. Each of the 8 items has 4 response options; 0 (Mild), 1 (Moderate), 2 (Mild) and 3 (Severe). The MG-ADL total score can be calculated by totalling all 8 items out of a maximum score of 24. A higher score indicates severe impairment.

The MG-QOL15r is a myasthenia gravis-specific health-related quality of life survey, which assesses the impact of myasthenia gravis over the past few weeks on the following domains: emotions, physical health, self-care, social life, and impact on role. Each of the 15 items has three response options: 0 (Not at all), 1 (Somewhat), and 2 (Very much). The MG-QoL15r total score can be calculated by totalling all 15 items out a maximum score of 30. A higher score indicates severe impairment.

The HADS is a frequently used self-rating scale developed to assess psychological distress in non-psychiatric patients. It consists of two subscales, Anxiety and Depression. The instrument comprises 14 items, 7 for the anxiety subscale and 7 for the depression subscale. Each item is scored on a 4-point response scale, scale wording changes for each item with each coding response corresponding with greater impairment or severity. Domain scores can be calculated by totalling all 7 items out of a maximum score of 21. High scores indicate greater severity of that impairment

The HUI3 is a generic 8-item survey, which provides descriptive evidence on multiple dimensions of health status, a score for each dimension of health, and a health-related quality of life score for overall health.Health dimensions include vision, hearing, speech, ambulation/mobility, pain, dexterity, emotion and cognition. Each dimension has five or six response options. It has recall periods of either 'usual health', the past week, two weeks, or four weeks. Scores on individual items are combined to given a combined health state which can then be converted to health utilities. Lower health utilities represent worse health.

This is a bespoke survey designed to understand the impact of COVID-19 on study participants. It includes questions about whether participants have had COVID, and the consequences if so, whether they have been vaccinated, and how the wider pandemic has affected their MG treatment and quality of life.

The SSQ is a single question that asks respondents what percentage of normal they feel with respect to their MG. The PASS is a single question that asks respondents whether they would consider their current disease state to be satisfactory if they had to stay in it for the next few months. The SSQ and PASS will be presented to participants at the same time, as a question pair.

The EQ-5D-3L is a three-level version of the EQ-5D-5L. It includes the same dimensions as the EQ-5D-5L, but each has only three levels: no problems, some problems, and extreme problems. The EQ VAS is unchanged from the EQ-5D-5L version.

The PROMIS sleep disturbance measure assesses self-reported frequency, severity, and duration of dyspnea (shortness of breath) over the last 7 days using either a 0-10 numeric rating scale or 0-4 rating scale to assess dyspnea characteristics.Each item is evaluated individually according to the numeric rating scale. No total score is calculated for this instrument. Higher scores on items indicate more severe symptoms.

The FACIT-Fatigue measure is a generic 13-item survey which assesses fatigue levels and impact over the past 7 days. The level of fatigue is measured on a 4-point Likert scale (4 = not at all fatigue to 0 = very much fatigued). Scores range from 0-52. The higher the score, the better the quality of life.

The PROMIS sleep disturbance measure assesses self-reported perceptions of sleep quality, sleep depth, and restoration associated with sleep over the last 7 days using a 5-point scale. Scores range from 6-30. Higher scores represent worse sleep disturbance.