OBJECTIVES: Myasthenia Gravis (MG) is a rare autoimmune disorder of the neuromuscular junction (NMJ) characterized by fluctuating weakness and fatigability of the voluntary muscles. The objective was to conduct a systematic literature review (SLR) to assess the incidence and prevalence of MG in US, EU5 and Japan.

METHODS: A literature review was performed using biomedical databases (MEDLINE®, EMBASE®) from 2007-2019. Studies published prior to 2007 were identified by bibliographic searching of systematic reviews. Additional supplementary web based searches were conducted to identify evidence from registries, conference abstracts and grey literature. The quality assessment of relevant studies was conducted and data was extracted.

RESULTS: A total of 34 studies reported data for US (8), UK (8), Spain (2), Italy (12) and Japan (4). Relevant literature was not identified for France and Germany. The prevalence and incidence of MG varied substantially across geographies. The prevalence ranged from 11.8 (Japan) to 64.9 (Italy) per 100,000 persons. Annual incidence ranged from 0.87 (Japan) to 10.4 (US) per 100,000 persons. MG prevalence has increased over time in Italy (11.1 in 1997 to 64.9 in 2014), Japan (1.2 in 1966 to 11.8 in 2011), UK (15 in 1998 to 40.1 in 2016), and US (3.2 in 1956 to 24.3 in 2011). A higher prevalence was reported among elderly population (≥65 years) compared to younger ages (<65 years) in Spain (122 vs 21.8 per 100,000) and UK (46.3 vs 12 per 100,000).

CONCLUSIONS: MG prevalence and incidence was lower in Japanese population compared to Caucasians due to genetic differences. The geographic variations may be due to demographic and methodological differences among studies. The increasing elderly population and enhanced diagnostic and treatment capability may be the reason for increase in prevalence and incidence rates of MG.