Burden of illness in patients with treatment refractory myasthenia gravis

Introduction: This study assessed the clinical burden of refractory myasthenia gravis (MG), relative to nonrefractory MG. Methods: Rates of myasthenic crises, exacerbations, inpatient hospitalizations, and emergency room (ER) visits over a 1-year period were measured for 403 refractory, 3,811 nonrefractory, and 403 non-MG control patients from two administrative health plan databases. Results: Compared with nonrefractory patients, a significantly greater percentage of refractory patients had at least one myasthenic crisis (21.3% vs. 6.1%; P < 0.001) and at least one exacerbation (71.2% vs. 32.4%; P < 0.001) over a 1-year period. Refractory patients were also significantly more likely to be hospitalized and/or have an ER visit than nonrefractory patients and non-MG controls (P < 0.001 for all). Discussion: Refractory MG patients have significantly greater clinical burden and are more likely to utilize intensive healthcare resources than nonrefractory patients. Furthermore, refractory patients may be at greater risk of crises throughout the disease course than previous studies have suggested. Muscle Nerve 58: 99–105, 2018.