December 19, 2024

expert reaction to study looking at a brief outpatient rehabilitation program (with a cognitive and behavioral approach) and self-reported physical function in people with long Covid

A study in JAMA Network Open looks at self-reported physical function in long Covid patients after participating in an outpatient rehabilitation program.

Prof Kevin McConway, Emeritus Professor of Applied Statistics, Open University, said:

“This is a well-designed and, in my view, well-conducted randomised clinical trial, and the methods of statistical analysis are appropriate.  As always, though, it’s important to be clear about what the findings mean.

“The researchers make it clear that it is a pragmatic randomised trial.  That is, they are not seeking to investigate exactly how the intervention, they are trialling, CBT, works.  Instead the point of a pragmatic trial like this is to investigate how effective a treatment is, in something close to everyday use in clinical practice, in comparison with some other treatment.  In this case they are comparing CBT with care as usual, for people with what’s commonly known as long Covid.  In brief summary, what they found is that a standard measure of self-reported physical functioning improved considerably more, at the end of the CBT treatments, in people that had had CBT, than it did in people who had had the usual (non-CBT) care over the same period of time.  Also there was essentially no change in this measure of physical function over a longer term (up to 12 months from recruitment) after the treatment.

“It’s worth pointing out that the researchers are not claiming that the CBT cured the long Covid, and in fact the average level of physical function in the CBT group remained below the average for the Norwegian general population after the treatment ended and for the longer follow-up period.  However, the researchers concluded that the better physical function was clinically significant – in other words, that the patients who had CBT did better on average, from a clinical point of view, than did the patients on usual care.  There’s good statistical evidence that the patients on CBT did better, but I can’t personally say whether the difference is important clinically, simply because I’m not a clinician (though I have no reason to doubt that it is).  As the researchers point out in the Discussion section of their paper, this isn’t the first randomised clinical trial to report a positive effect of CBT.

“There are some limitations.  The trial was carried out only in one centre – other places may have different patient populations, may not use CBT in an identical way, and may have different standard and type of ‘care as usual’ as a comparator.  The patients in this trial had, at worst, what was classed as moderate symptoms when they entered the trial, and hardly any of them had been hospitalised with Covid, so the trial can’t say anything direct about how effective CBT might be in patients with more serious symptoms.

“Also, the nature of CBT means that the treatment could not be disguised from the patients, and the researchers point out that those on usual care had less attention from clinicians that did those who received CBT.  So the trial can’t rule out the possibility that the CBT was more effective simply because of the extra attention the CBT patients received, or because they knew they were receiving a different treatment from the usual.  I’d argue that, in the context of a pragmatic clinical trial, these points are not crucial.  The aim is not to see how the CBT worked, but only to determine whether, in fact, it worked more effectively that the usual care in this centre.

“The researchers explain the theoretical reasons for the using CBT in general, and indeed for the particular CBT intervention they used.  These reasons are to do with interactions between mind and body – though the researchers are certainly not saying they think that long Covid is ‘all in the mind’.  But again, because this is a pragmatic trial, it doesn’t matter to the evaluation of the effectiveness of the CBT whether the researchers’ theoretical reason for using CBT are valid.  The only point of the trial is to find out whether it works effectively, in comparison with care as usual at this centre.

“As in pretty well any clinical trial of any treatment, there will be some patients for whom CBT is not effective at all.  It will also be more effective than average, or less effective than average, in different individuals.  And things may (or may not) look considerable different in other centres.  That’s why the researchers conclude that future research should look at what elements of their approach are the most effective, and should identify subgroups for which various treatments are most effective.”

‘Brief Outpatient Rehabilitation Program for Post–COVID-19 Condition: A Randomized Clinical Trial’ by Tom Farmen Nerli et al. was published in JAMA Network Open at 16:00 UK time on Thursday 19 December 2024.

DOI: 10.1001/jamanetworkopen.2024.50744

Declared interests

Prof Kevin McConway: “Previously a Trustee of the SMC and a member of its Advisory Committee.”