P229 Cardiopulmonary exercise testing in patients with long covid 2022 Mistry et al

Abstract
Objective Examine the relationship between symptoms and exercise physiological parameters in patients with long covid.

Methods Patients with long covid symptoms 6–12 months after covid19 infection referred to the long covid clinic were invited for Cardiopulmonary Exercise Testing (CPET). None had required ventilatory support during covid19 infection. All patients had normal transthoracic echocardiograms and normal resting flow-volume curves and gas transfer measurements. All patients underwent standard cycle ergometer symptom-limited CPET. Treatment guided by the CPET was offered and follow-up CPET was performed at 3 months.

Results 32 patients had a first CPET. The commonest symptoms were breathlessness (30/32), fatigue (26/32), cough (7/32), ‘brain fog’ (6/32) and chest pain (5/32). The main CPET physiological abnormalities were a borderline low peak oxygen uptake (mean 82.5% predicted), a low anaerobic threshold (AT, mean 47.6% of predicted maximal oxygen uptake) and a low oxygen uptake/work rate slope (mean 9.4 ml/min/W). The oxygen pulse curve flattened early in exercise, but peak oxygen pulse was normal (mean 88.9%).

20 patients underwent a second CPET. 14 patients had improved symptoms: breathlessness (11/20), fatigue (9/20), cough (2/20), ‘brain fog’ (3/20) and chest pain (0/20). Symptom improvement was associated with a rise in peak oxygen uptake (to mean 85.3% predicted) and oxygen pulse (to mean 94.1% predicted) although both remained within the normal range. The AT remained low (mean 46.4% predicted maximal oxygen uptake). The ventilatory equivalent for carbon dioxide (VE/VCO2) was normal 28.6 L/L at AT.

6 patients with unchanged symptoms had a reduction in oxygen pulse to mean 81.5% predicted compared to the first CPET but a rise in VE/VCO2 to 33.7 L/L at AT.

Conclusions

1. Long covid is associated with impaired peak oxygen uptake, AT and oxygen pulse. This suggests an oxygen delivery or uptake disorder or deconditioning. The transthoracic echocardiograms were normal suggesting a disorder at the muscle level.
   
   
2. A targeted treatment programme based on CPET improves symptoms and physiological parameters in long covid patients.

Patients with unchanged symptoms after 3 months of treatment had persistent physiological abnormalities but appeared to develop features of dysfunctional breathing syndrome.

https://thorax.bmj.com/content/77/Suppl_1/A206

 

That's a 38% loss of data. No one in their right mind would use anything where 38% of the data from an experiment is not accounted for. It would be different if there were some obligation to account for the missing data but nooooo, instead it's basically abused to eke out fake signal out of noise that is at least 38% to begin with.

And with the article paywalled, it's impossible to tell what this "treatment programme" comes from or what it is has to do with CPET. Especially with a 38% loss of data. Are they attributing the 14 patients who improved to the CPET? What is happening here? How is medical research so scattershot and weird?

I wouldn't change my mind much about sausages seeing what goes on in a sausage factory. I have a good idea already. But seeing this? Now that is cause for concern. I'm starting to see why the automatic reflex to attack anyone who criticizes anything out of medicine, if people saw how it works behind the scenes they would be horrified and rightfully so.