Serious infections in patients with myasthenia gravis: population‐based cohort study

Abstract

Background and purpose To characterize the frequency and risk of serious infections in patients with myasthenia gravis (MG) relative to age/sex/area‐matched comparators. Methods This was a population‐based cohort study in Ontario, Canada of patients with newly‐diagnosed MG and 1:4 age/sex/area‐matched general population comparators accrued from 1 April 2002 to 31 December 2015. The main outcome was a serious infection, defined by a primary diagnosis code on a hospitalization or emergency department record. We computed crude overall and sex‐specific rates of infection among patients with MG and comparators, and the frequency of specific types of infection. Adjusted hazard ratios and 95% confidence intervals were estimated using Cox regression. Results Among 3823 patients with MG, 1275 (33.4%) experienced a serious infection compared with 2973/15 292 (19.4%) of comparators over a mean follow‐up of over 5 years. Crude infection rates among patients with MG were twice those in comparators (72.5 vs. 35.0 per 1000 person‐years, respectively). The most common infection types were respiratory infections, particularly bacterial pneumonia. After adjustment for potential confounders, MG was associated with a 39% increased infection risk (adjusted hazard ratio, 1.39; 95% confidence intervals, 1.28–1.51). Conclusions Patients with MG are at a significantly higher absolute and relative risk of serious infections compared with age/sex/area‐matched comparators. This needs to be considered when selecting MG treatments and when planning vaccination/prophylaxis. Determining whether this risk is due to the use of immunosuppressive medications (vs. MG itself) is an important area for future research.

Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial

“…The rate of infections is of special interest because patients with myasthenia gravis are predisposed to infec tions, probably exacerbated by concomitant immuno suppressive treatments. 31,32 In the efgartigimodtreated group, 46% of patients had an infection compared with 37% in the placebo group. Most infections were mild to moderate, with only two graded as severe in the efgartigimodtreated patients.…”

Neuromuscular Diseases Care in the Era of COVID-19

“…Long term corticosteroids is the drug that increase most the risk of infections (20-50%) (23,24) and are often administered in various NMDs: MG, chronic dysimmune neuropathies, Duchenne/Becker Muscular Dystrophy (DMD/BMD) and patients with spinal muscular atrophy (SMA) treated with Onasemnogene abeparvovec-xioi (steroids must be administered for the first 2 months since the administration of the gene therapy). Although considered a risk factor given the associated immunosuppression, in general terms they should not be discontinued abruptly as they can cause a worsening of the underlying disease.…”

Opinions on Pneumocystis jirovecii prophylaxis in autoimmune neuromuscular disorders

“…In rheumatologic patients, the estimated overall PJP incidence is approximately 2% to 3%, being highest for systemic vasculitic conditions like granulomatosis with polyangiitis (1.5% to 30%) and much lower for rheumatoid arthritis (0.1% to 0.3%) 10‐15 . Available data suggest that the incidence of PJP in patients with myasthenia gravis (MG) and nonsystemic autoimmune neuropathies is less than 1%, whereas the incidence in autoimmune myopathies is less than 2% 16‐22 …”