On 2014 Jan 04, Tom Kindlon commented:
The dropping of actometers as an outcome measure and other points relating to the outcome measures being used
(I'm posting this e-letter/comment from 2008 here for the same reason as the first e-letter below)
In their reply to my comments, Peter White and colleagues say they are using [i]"several objective outcome measures"[/i] [1]. If they think these tests are useful as objective outcome measures, why is at least one of them not being used as a primary outcome measure rather than the current situation where there are only two subjective outcome measures being used.
I have already made some points on the outcome measures but another one is that the bimodal Chalder Fatigue Scale hardly seems a very good outcome measure for a "CFS/ME" trial where there is likely going to be so many maximum or near maximum scoring initially[2]
Also, there are so many (14) secondary outcome measures in this study, along with so many (18) predictor variables, that it seems unlikely all the different methods of looking at the secondary outcome measures can be explored in the final published paper, given authors are encouraged not to make papers too long (especially journals that have paper editions). The protocol itself is 20 pages long when all the different aspects of it are listed! At least some of the information will need to be re-iterated in the final paper.
It is of course important to take the burden on participants into account when deciding what outcome measures to use. However I find the following point very strange:
"Although we originally planned to use actigraphy as an outcome measure, as well as a baseline measure, we decided that a test that required participants to wear an actometer around their ankle for a week was too great a burden at the end of the trial." Firstly they clearly don't find it that great a burden that they drop it altogether as it is being used on patients before the start. If they feel it was that big of a burden, it should probably have been dropped altogether.
Of course, other studies in the area have used measuring over a similar or longer period. For example, Bazelmans [3] used an actometer over 14 days, Black [4] used actigraphy over 14 days, Sisto[5] used actigraphy over 7 days, Vercoulen[6] used an actometer over 12 days and Van der Werf [7] used an actometer for 12 days.
Also if one wants to reduce the burden on patients, why not take out one or both of the exercise tests instead. As the clinicians in the study would know, post-exertional symptoms are part of the condition.
For example, Nijs[8] performed a gentle walking exercise on patients where they walked on average 558m(+/-340) (range: 120-1620) at a speed of 0.9m/s (+/-0.2) (range: 0.6-1.1). This resulted in a statistically significant (p<0.05) worsening of scores in the following areas when comparing pre-exercise, post-exercise and 24 hour post-exercise scores using ANOVA: VAS fatigue, VAS musculoskeletal pain, VAS sore throat, SF-36 bodily pain and SF-36 general health percention. 14 out of 24 subjects experienced a clinically meaningful change (worsening) in bodily pain (i.e. a minimum change of the SF-36 bodily pain subscale score of at least 10).
Those results are similar to another study[9] which involved the acute effects of 10 discontinuous 3-minute exercise bouts on a treadmill in 10 CFS patients. In between exercise bouts, there was a 3-minute recovery period between exercise bouts. The participants walked at a comfortable walking pace self-selected by the subjects. On average, the subjects walked at a speed of 0.71+/-0.20 m/s. Some patients reported experiencing headaches, leg pain, fatigue or sore throats.
In another study, Lapp [10] (not to be confused with Clapp[9]) reported on the effects of 31 patients to his practice who were asked to monitor their symptoms three weeks before to 12 days after a maximal exercise test. 74% of the patients experienced worsening fatigue and 26% stayed the same. None improved. The average relapse lasted 8.82 days although 22% were still in relapse when the study ended at 12 days. There were similar changes with exercise in lymph pain, depression, abdominal pain, sleep quality, joint and muscle pain and sore throat.
These are just a small selection of the studies which show patients experience an exacerbation of their symptoms following exercise testing. So these are the sorts of symptoms the patients may expect following the exercise. This reminds me that there seems to be a lot of concentration on measuring fatigue in this study - there are many other symptoms that are part of "CFS/ME".If they had used actometers instead of, say, doing one of the exercise tests, the response to the exercise could have been followed to see how long and how severe an effect the exercise had on the patient. Or they could have dropped both the exercise tests altogether.
As well as "subjective" findings following exercise testing, there have also been objective findings. Arnold et al[11] found excessive intracellular acidoss of skeletal muscles with exercise. Jammes[12] found an increase of damaging oxidative stress following exercise testing. So patients could not just endure temporary sysptom but possibly also longer-term harm from exercise testing. There are numerous other exercise abnormalities.As the clinicians involved in the study probably hear from patients, one of the frustrating things about ME or CFS is that people don't realise the payback that they can have from doing things. This would have been an opportunity to investigate this as part of the study. But now the effort patients will put in and the payback they will feel in some ways is being wasted as the effects won't be measured.
Anyway, to repeat again, given the authors familiarity with the literature, I find it strange that they would decide using an actometer would be worse than putting patients through two exercise tests.
I also find it surprising that in a study part-funded by the Department of Work and Pensions (DWP) that the objective outcome measures (not involving questionnaires) are all once-off exercise tests. It has been established that patients need to be able to do things on several days during a week before they can be passed fit for work. I have mentioned using actometers following exercise tests after an exercise test above; of course, actometers wouldn't have to be used at that time but also during a "normal week".
Proponents of pacing methods including APT would say that there is a "ceiling of activity" that patients can't go above without experiencing a worsening of symptoms. Black[13] has found evidence of this. Proponents of CBT or GET for "CFS/ME" would suggest that patients can gradually just increase how much activity they can do. Actometers would also have tested the hypothesis. As it stands, the study will not give us information on this as just because patients answer questionnaires saying they're improved (which could simply be because they think they're better) or improve their exercise results (which might simply be because they're willing to push themselves more) doesn't prove that they don't have an activity ceiling above which they experience disabling symptoms (esp. when, as in this study, there is no follow-up period following the exercise testing). This is the real "heart" of the issue but given the current design, the question won't be answered.
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