Respiratory Muscle Dysfunction and Associated Risk Factors Following COVID-19-Related Hospitalisation

Background: Studies have highlighted long-term respiratory muscle dysfunction in COVID-19 survivors, although the underlying risk factors remain unclear. This single-center study assessed respiratory muscle function and individual associated factors at follow-up in patients hospitalised with COVID-19 and related acute respiratory failure. Methods: Data were collected for consecutive patients, aged ≥18 years, at the post-COVID outpatient service of Hospital Policlinico in Modena (Italy) in the time frame of 3 to 6 months after discharge. Data were analysed using single and multiple logistic regression model. Correlation between MIP/MEP, hand-grip values and lung function were further explored. Results: Out of 223 patients (mean age 67 years, 69% male) 121 (54.3%) exhibited MIP or MEP dysfunction which was found to be associated with use of non-invasive ventilation (OR=1.93 [1.08–3.52], p=0.03) and female gender (OR=1.96 [1.1–3.57], p=0.03) as indipendent risk factors. A positive correlation was observed between MIP dysfunction and hand-grip strength (p=0.03 and 0.01), whereas both MIP and MEP were significantly associated with FEV1, FVC, TLC, and DLCO. Conclusions: Respiratory muscle dysfunction is consistently prevalent and parallels peripheral muscle weakness and lung fuction level in patients at follow up after severe COVID-19. The need for non-invasive ventilation during the acute phase and female gender might represent risk factors. MIP/MEP assessment should be recommended to observe respiratory muscle dysfunction in severe post-COVID survivors.