Inclusion body myositis (IBM) can result in deadly respiratory consequences. Yet, the mechanism driving this issue remains equivocal. We mapped the literature to identify physiological respiratory characteristics in IBM and the types of respiratory assessments used. We performed a scoping review using seven databases and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Our search yielded 381 studies, of which 17 studies were reviewed. Case studies/series predominated (53%). Studies mainly used pulmonary function testing (76%), suggesting restrictive respiratory abnormalities. However, insufficient reporting of race/ethnicity (82%), disease duration (59%) and severity (77%), and assessment operations (82%) and interpretation (59%) protocols were problematic. Half of the studies relied on standalone assessments, and 75% of studies that reported interpretation protocols applied interpretation cutoff thresholds. Low-level evidence guides our understanding of IBM-induced respiratory dysfunction. Future studies should ensure detailed and transparent reporting and follow current best practices for respiratory assessment to define IBM-induced respiratory dysfunction.
Ambrocio et al. (Mon,) studied this question.