Effect of a home-based inspiratory muscle training programme on functional capacity in postdischarged patients with long COVID: the InsCOVID trial

Abstract

BackgroundFatigue and exercise intolerance are the most common symptoms in patients with long COVID.AimsThis study aimed to evaluate whether a home-based inspiratory muscle training (IMT) programme improves maximal functional capacity in patients’ long COVID after a previous admission due to SARS-CoV-2 pneumonia.MethodsThis study was a single-centre, blinded assessor, randomised controlled trial. Twenty-six patients with long COVID and a previous admission due to SARS-CoV-2 pneumonia were randomly assigned to receive either a 12-week IMT or usual care alone (NCT05279430). The physiotherapist and participants were not blinded. Patients allocated to the IMT arm were instructed to train at home twice daily using a threshold inspiratory muscle trainer and to maintain diaphragmatic breathing during the training session. The usual care arm received no intervention.The primary endpoint was the change in peak oxygen consumption (peakVO2). Secondary endpoints were changes in quality of life (QoL), ventilatory efficiency and chronotropic response during exercise (evaluated by chronotropic index-CIx- formula). We used linear mixed regression analysis for evaluating changes in primary and secondary endpoints.ResultsThe mean age of the sample and time to first visit after discharge were 50.4±12.2 years and 362±105 days, respectively. A total of 11 (42.3%) were female. At baseline, the mean of peakVO2, ventilatory efficiency and CIx were 18.9±5 mL/kg/min, 29.4±5.2 and 0.64±0.19, respectively. The IMT arm improved their peakVO2significantly compared with usual care (+Δ 4.46 mL/kg/min, 95% CI 3.10 to 5.81; p<0.001). Similar positive findings were found when evaluating changes for CIxand some QoL dimensions. We did not find significant changes in ventilatory efficiency.ConclusionIn long COVID patients with a previous admission due to SARS-CoV-2 pneumonia, IMT was associated with marked improvement in exercise capacity and QoL.Trial registration numberNCT05279430.

Can inspiratory muscle training benefit patients with COVID‐19? A systematic review and meta‐analysis

“…Six eligible studies were added together in our meta‐analysis, which all in all, resulted in 210 patients in the experimental group and 139 patients in the control group. Five studies enrolled patients with post‐COVID‐19 conditions 14–16,19,20 . Three studies included patients who had been hospitalized for COVID‐19 15,19,21 and one study included patients who had never been hospitalized for COVID‐19 20 .…”

“…20 Only one study compared IMT to sham IMT 16 while the other five studies compared IMT to other PR programs or no training. Four studies conducted the IMT program in a home-based way via a threshold pressure device 14,16,19,20 while the other two studies were under supervision in health facilities. 15,21 Details of included studies were shown in Table 1.…”

Respiratory Muscle Strength Training in Patients Post-COVID-19: A Systematic Review

“…However, in those studies that used the 6MWT to measure physical capacity, outcomes ranged from 42.1 to 119.1 m post-intervention, which exceeds the reported MCID of 30 m for the 6MWT in those with chronic lung disease (Singh et al, 2014). Five studies used a home-based respiratory muscle-strengthening exercise as a standalone intervention (Abodonya et al, 2021; Del Corral et al, 2023a; McNarry et al, 2022; Morgan et al, 2023; Palau et al, 2022).…”

“…Some studies did not mention or have blinding processes related to study design, leading to n/a ratings in this category (Table 1). Using the OCEBM instrument to evaluate the level of evidence for each study, six of the studies had a 1b level of evidence (Del Corral et al, 2023a;Jimeno-Almazan et al, 2023;Liu et al, 2020;McNarry et al, 2022;Nagy et al, 2022;Palau et al, 2022), three had a 2b level of evidence (Abodonya et al, 2021;Hayden et al, 2021;Nopp et al, 2022), and two had a 2c level of evidence (Hockele et al, 2022;Morgan et al, 2023) (Table 2). These relatively high levels of methodological quality led to the inclusion of these studies in the review.…”

“…Among the 11 included studies, five were randomized controlled trial studies (Del Corral et al, 2023a;Jimeno-Almazan et al, 2023;McNarry et al, 2022;Nagy et al, 2022;Palau et al, 2022), one was quasi-experimental (Liu et al, 2020), and five were prospective (Abodonya et al, 2021;Hayden et al, 2021;Hockele et al, 2022;Morgan et al, 2023;Nopp et al, 2022). All of the studies focused on respiratory muscle strength training in individuals experiencing post-COVID-19 symptoms, with four including an aerobic or peripheral strengthening exercise component in the intervention (Hayden et al, 2021;Hockele et al, 2022;Liu et al, 2020;Nopp et al, 2022), and one including a diaphragmatic release intervention (Nagy et al, 2022).…”