Effect of a home-based inspiratory muscle training programme on functional capacity in postdischarged patients with LC: the InsCOVID trial 2022 Palau

Abstract

Background
Fatigue and exercise intolerance are the most common symptoms in patients with long COVID.

Aims
This 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.

Methods
This 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.

Results
The 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 peakVO2 significantly 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 CIx and some QoL dimensions. We did not find significant changes in ventilatory efficiency.

Conclusion
In long COVID patients with a previous admission due to SARS-CoV-2 pneumonia, IMT was associated with marked improvement in exercise capacity and QoL.

Open access, https://bmjopenrespres.bmj.com/content/9/1/e001439

 

Regardless of the details and the loose applicability, one of their conclusions is that home-based is equivalent to a supervised program, in that they produce similar results without really saying nothing else about it. Which we've known for a long time. Same with mobile apps doing CBT, it's just as useful as dozens of séances with a therapist, because it's fully generic and very trivial, especially as any benefit from better fitness will only keep applying as long as it's continuously maintained. A study of holding their breath showing they can improve on this with time tells us about as much as this here.

I remain convinced that this type of study tells us nothing useful. It's too subject to bias and manipulation and about as valid as someone's opinion.

 

It’s got to the stage when I have no idea if I have read about the various new LC studies or not. They all are increasingly repetitive, inconclusive and simplistic.

 

It suggests that persistent dyspnea was not the cause of the drop in VO2 peak (and potentially other symptoms as well).

VO2Max is about how much oxygen can be delivered to the muscle - people with severe lung disease, or athletes who have reached their peak physical (aerobic) fitness can be limited by the lungs, but everyone else is limited by the heart/vascular system.

Lastly, the differences is QoL ratings can be typical response bias - this study is not conclusive by any means.

Note that part of the difference between groups was a drop in VO2Peak in the non-intervention group of around 5%, compared to a 22% increase in the intervention group. VO2Max is actually more fluid than people realise - many studies show healthy people can achieve 25-30% VO2Peak gains in 10 week programmes and 2 weeks of inactivity compared to prior activity patterns can lead to a 10% drop (it doesn't keep dropping, the body adjusts to the new activity level).