Factors associated with increased severity of generalized myasthenia gravis among patients in the United States and Europe

Abstract

Among individuals with generalized myasthenia gravis (gMG), risk factors for increased severity over time are unknown. This study examined the association between demographic and clinical variables and patient progression to a more severe MG Foundation of America (MGFA) classification. Data were drawn from the Adelphi Real World myasthenia gravis Disease Specific Programme™, a cross-sectional survey capturing retrospective data from patients' medical histories. Among 421 individuals, 16% experienced increased gMG severity (progression to higher MGFA class between diagnosis and the time of the survey, 1-7 years later) and for 84%, gMG was stable/improved (MGFA class the same/lower). Logistic elastic net regression determined that increased severity was associated with the occurrence of prior misdiagnosis. Bivariate analyses indicated significant associations between increased severity and longer time between symptom onset and (a) the first consultation with a healthcare practitioner and (b) MG diagnosis. Increased severity was also associated with older age and presence of specific symptoms at diagnosis. gMG stability/improvement was associated with employment status and general fatigue at diagnosis. There is a need for prompt and accurate diagnosis and improved treatment options with the potential to increase the likelihood of stability/improvement for gMG patients.

Keywords: Cross-sectional studies; Misdiagnosis; Myasthenia gravis; Outcome; Real-world evidence; Severity.

Fig. 1

Features of the diagnostic journey for patients with gMG who were diagnosed 1–7 years prior to the survey, stratified according to whether gMG severity had increased or remained stable/improved since gMG diagnosis: (a) time to first consultation, (b) time to diagnosis, (c) proportion of patients who received a misdiagnosis, and (d) condition incorrectly diagnosed prior to gMG diagnosis. gMG, generalized myasthenia gravis; HCP, healthcare practitioner. ^aProgression to a higher MGFA class between diagnosis and the time of the survey; ^bMGFA class either the same at diagnosis and the time of the survey or lower between diagnosis and the time of the survey; ^cThis included transient ischemic attacks and posterior circulation stroke. *p < 0.05; **p < 0.001. Panels a and b show mean and standard deviation. Panel c shows percentage. Panel d shows conditions diagnosed in ≥ 5% of either cohort.

Fig. 2

Positive associations between patient sociodemographic/clinical variables and the likelihood of increased gMG severity (versus remaining the same/improving) since diagnosis, among patients with gMG who were diagnosed 1–7 years prior to the survey. gMG, generalized myasthenia gravis. ^aProgression to a higher MGFA class between diagnosis and the time of the survey; ^bMGFA class either the same at diagnosis and the time of the survey or lower between diagnosis and the time of the survey.