Trial Report Effect of normobaric and hyperbaric hyperoxia treatment on symptoms and cognitive capacities in Long COVID patients: [placebo RCT], 2025, D’hoore+

[forestglip]

Effect of normobaric and hyperbaric hyperoxia treatment on symptoms and cognitive capacities in Long COVID patients: a randomised placebo-controlled, prospective, double-blind trial

Leen D’hoore, Peter Germonpré, Bert Rinia, Leonard Caeyers, Nancy Stevens, Costantino Balestra

[Line breaks added]

Introduction
Long COVID syndrome is a major health issue. Multiple treatments have been proposed but efficacy is inadequately investigated. Hyperbaric oxygen therapy (HBOT) has been promoted based on a small number of publications. As there is potential for a placebo effect and the financial cost of HBOT is high, we sought to investigate the effects of HBOT in Long COVID in a randomised trial.

Methods
We randomised 101 patients into four treatment groups, receiving 10 sessions of oxygen ‘treatment’ inside a pressure chamber, according to one of four modalities: A – 100% oxygen at 253 kPa (2.5 atmospheres absolute); B – 40% oxygen at 253 kPa; C – 100% oxygen at 101.3 kPa (1 atmosphere absolute); D – 21% oxygen at 101.3 kPa. Groups B and C thus received a similar effective oxygen dose of 101.3 kPa.

Quality of life symptom scores (Visual Analogue Scale; EQ-5D-5L, C19-YRSm), a 6-minute walking test and five neurocognitive tests were administered before and after the treatment series. At three months post-treatment, a telephone questionnaire probed for lasting effects.

Results
All groups were comparable with regards to demographics, Long COVID symptoms and severity. After treatment, there were no significant differences in subjective symptoms, functional scores, and cognitive performance between any groups.

The response to treatment was highly variable, with some patients in even the ‘placebo’ group D reporting a significant improvement in their well-being. This was not reflected in any objective outcome scores. No subgroups of patients responded better to any of the treatments.

Conclusions
There was no significant effect from different doses of oxygen in a hyperbaric chamber. It is possible that the very modest improvements reported in other studies were due to a placebo effect. Claims that HBOT has a significant effect on Long COVID need further investigation before indiscriminately prescribing or promoting HBOT.

Link (Diving Hyperbaric Medicine) [Paywall?]

 

[rvallee]

The response to treatment was highly variable, with some patients in even the ‘placebo’ group D reporting a significant improvement in their well-being. This was not reflected in any objective outcome scores.

This is the correct framing. This is essentially identical to all trials done in ME/CFS, including PACE, which frame the same results as being undeniably effective. It's exactly what we find all over alternative medicine: people report a bit positively, but it makes no difference. It's even a common joke, the difference between medicine and alternative medicine? Medicine works. Objectively. "Feeling a bit better" is something every single alternative medicine practitioner happily reports, truly or not. It is not a valid benefit when it has nothing to do with the problem.

So much is contained in so few words:

Multiple treatments have been proposed but efficacy is inadequately investigated.

It's truly remarkable how mostly identical things are interpreted in completely different ways. In psychobehavioral hands, if this were some psychobehavioral woowoo, this would be a rousing success and anyone saying otherwise is being a big meany to the idea of mental illness. In other hands, like this, they simply report results in simple words and that's that.

Something that will radically have to change in medical research is honest reporting using clear, simple language. This paper does that. Almost all research on chronic illness fails to do so, with the explicit intent of misreporting failure into the appearance of success.

But the main difference is that most patients will accept those results, because we want something that is truly effective, a dramatic contrast with most evidence-based medicine, where the motivations are more in line with "I spent 5 hours cooking this horrible inedible mess, and by god you will eat it and you will pretend to like it".

 

[Utsikt]

Nice to see a properly done trial for once, with what appears to be correct reporting of the outcomes if the abstract is to be believed.

All but the last author are affiliated with Centre for Hyperbaric Oxygen Therapy, Queen Astrid Military Hospital, Brussels, Belgium. A positive result would have been a goldmine for them. Kudos for following the evidence.

 

[hotblack]

A positive result would have been a goldmine for them.

Do they sell services privately or are they focused on military personal? I’m not sure how it works in Belgium. But possibly because they’re a military hospital is why they care about rigour and results, that is they’re focused on finding effective treatments for personal.

 

[Utsikt]

Do they sell services privately or are they focused on military personal? I’m not sure how it works in Belgium. But possibly because they’re a military hospital is why they care about rigour and results, that is they’re focused on finding effective treatments for personal.

According to this, it also serves the public. It specialises in the following areas:
emergency and disaster medicine
acute and chronic treatment of serious injuries and rehabilitation
surgical treatment of locomotor disorders and rehabilitation
mental health care, with particular emphasis on crisis psychology
infectious diseases and tropical medicine
hyperbaric medicine
specialised medicine
aeronautical medicine
hypobaric medicine

---