Long-term Use of Oral Corticosteroids and Overall Survival Among Patients with Myasthenia Gravis: A Nationwide Population-based Study
Qian Cai1, Kavita Gandhi2, Nurgul Batyrbekova3, Gabriel Isheden3, Maria Ait-Tihyaty4, Winghan Jacqueline Kwong1
1Janssen Global Services, Health Economics & RWE, USA, 2Janssen Global Services, Market Access Neuroscience, USA, 3Cytel, Real World Evidence, Sweden, 4Janssen Global Services, Global Medical Affairs Neuroscience, Canada
Objective:

To assess the association between long-term oral corticosteroids (OCS) exposure and overall survival (OS) among patients with myasthenia gravis (MG).

Background:

MG is a rare autoimmune neuromuscular disease characterized by muscle weakness and fatigability. OCS are widely used to treat MG; however, the impact of long-term OCS use on OS in patients with MG is unclear.

Design/Methods:

Data for adult patients with ≥1 primary diagnosis of MG (ICD-10-SE G70.0) provided by neurologist from 01-Jan-2006 to 30-Dec-2020 were extracted from four linkable, longitudinal, nationwide population-based Swedish registries. Patients having ≥1 OCS prescription on or after the MG diagnosis and ≥12-month follow-up period were included. Long-term OCS use was defined as continuous OCS use for ≥3 consecutive months and without gaps of >60 days between prescriptions or end of data availability during the 12 months after MG diagnosis (landmark period); patients not meeting these criteria were defined as short-term users. OS was assessed from the end of landmark period to end of follow-up. OS rates were adjusted for age, gender and other differences in Cox-regression models.

Results:

A total of 1,942 patients were included; 272 (22%) were long-term OCS users (mean [SD] age: 65.2 [17.1] years; female, 48.5%); 964 (78%) were short-term OCS users (age, 63.4 [17.0] years; female, 47.4%]). Median OS in long-term OCS users was 10.9 years vs 13.5 years among short-term users (log-rank test: P<0.01). After covariate adjustment, long-term OCS users had a significantly higher risk (42%) of death vs short-term users (adjusted HR: 1.42; 95% CI: 1.10–1.83).

Conclusions:
Long-term OCS use was associated with lower OS among patients with MG in Sweden highlighting potential limitations of OCS use and unmet need for safe and effective treatments in this population.  
10.1212/WNL.0000000000211310
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