No sex-based differences in odds of starting or time to treatment of generalized myasthenia gravis: A single center cohort study

Benjamin Beland MD, Tefani Perera MD, Angela Lee MD, Jamie Greenfield MPH, Lawrence Korngut MD, FRCPC, Gordon Jewett MD, FRCPC

Introduction/Aims Females with generalized myasthenia gravis (gMG) report lower quality of life (QoL) and have more severe disease than males. Sex differences in disease characteristics exist, however whether there are sex differences in the treatment of gMG that may contribute to QoL disparities is unknown. Our objective is to determine whether there are sex differences in the treatment of gMG.

Methods We performed a single-center retrospective study of people diagnosed with gMG at the University of Calgary between 1997 and 2021. Primary outcome was proportion starting treatment and secondary outcome was time from diagnosis to treatment initiation. Treatments included pyridostigmine, prednisone, steroid sparing therapies (azathioprine, mycophenolate mofetil [MMF], methotrexate [MTX], or tacrolimus), intravenous immunoglobulin (IVIg), plasmapheresis, rituximab, eculizumab, cyclosporine, stem cell transplantation, and thymectomy. Multivariable logistic and Cox proportional hazards regression models were used to examine treatment associations with sex, adjusted for time from onset to diagnosis, age at diagnosis, presence of thymoma, and antibody status.

Results A total of 179 people with gMG were included (41.9% female). Odds of starting treatment were not statistically associated with sex after adjustment for confounders and correction for multiple testing. Results of the secondary analysis using time to treatment initiation as the outcome were similar.

Discussion We found no sex differences in odds of starting treatment or time to treatment initiation that might explain previously observed sex-based differences in QoL. Future work should capture physician and patient treatment preferences that may influence disease management.

---