One‐year follow‐up of disease burden and medication changes in patients with myasthenia gravis: From the MG Patient Registry

INTRODUCTION/AIMS: We studied the progression of myasthenia gravis (MG) disease burden and medication adjustment among MG Patient Registry participants. METHODS: Participants diagnosed with MG (age ≥18 years), registered between July 1, 2013 and July 31, 2018 and completing both 6‐ and 12‐month follow‐up surveys, were included in this investigation. Participants were grouped into high‐burden (Myasthenia Gravis Activity of Daily Living scale [MG‐ADL] score ≥6) and low‐burden (MG‐ADL <6) groups based on MG‐ADL scores at enrollment. Demographics and disease history were compared between groups. MG‐ADL score change and medication changes (escalation, no change, de‐escalation) between enrollment and 12‐month follow‐up were compared between groups. Minimal symptom expression (MSE, MG‐ADL <2) at 12 months was compared between groups. Logistic regression analysis was performed to study factors associated with MSE at 12 months. RESULTS: In total, 520 participants (56% female) were included in high‐burden (n = 248) and low‐burden (n = 272) groups. Those in the high‐burden group were more likely to be younger, female, and have shorter disease duration. At 12 months, MSE was achieved in 6% of the high‐burden group and newly achieved (42 of 201, 21%) or maintained (52 of 71, 73%) in the low‐burden group. In the multivariable analysis, being in the high‐burden group and use of pyridostigmine were associated with less likelihood of MSE, whereas MG‐ADL score improvement (>2 or >20%) at 6 months significantly increased the likelihood of achieving MSE at 12 months (P = .0004). DISCUSSION: In both groups, but more so in the high‐burden group, patients infrequently achieved MSE after 1 year of MG treatment. Baseline low disease burden, improvement at 6 months and no pyridostigmine use were associated with a higher likelihood of MSE at 12 months.