Measures of outcome for trials and other studies

[Jonathan Edwards]

@Jonathan Edwards, I know you're not keen on the SF-36 scales, but I think SF-36 physical function has some benefits:

1. It's widely used, so you can compare scores with the general population and patients with other illnesses. That's been very useful when analysing e.g. the pace trial outcomes.
2. It doesn't have a ceiling effect in terms of poor health, or severely poor health. So deterioration and improvement in very ill patients can be monitored. (The chalder fatigue scale is a horrendously unhelpful scale because a significant proportion of patients score close to the maximum score, so deterioration can't be measured in all patients.)
3. It's a less relative/subjective questionnaire: It asks questions about engagement in specific activities rather than asking you to rate subjective symptoms in relation to a previous (long-forgotten) health status.

I think perhaps the the biggest negative is that, to keep things simple, the questions aren't very nuanced, and so it's not a very subtle measure of change.

I'm not familiar with many other self-report scales, so I can't compare it with many others, but I've always thought that SF-36 physical function is OK-ish for a broad indicator of changes in function.

I don't know if others would agree.

I am happy to accept that there is value to be found in these scores but I am still wanting to get clear in my head what each component of a composite would really do. So I am not so much disagreeing with anyone as throwing out thoughts about where things do not quite gel for me.

The potential for comparisons with other studies I can see is an advantage, although one might worry about context dependent biases. So gathering an SF-36 dataset might be a good thing for such secondary purposes.

There also seems to be an issue about remembering previous status. Some people here have suggested that it is easier to compare two levels of well being than give an absolute indicator at any one time. (I think the outcome measure has to be a comparison so that is fine from that angle.) But others have suggested that it is easy to forget what you were like at the beginning. What would seem sensible to me would be for the trialist and patient to go through all the issues that impact on the global illness problem, symptomatic and functional and to record them. SF-36 may be a good way to collect those data and if it is done again at the end then you have a pretty good idea of what the comparison is. (Looking back at the old score may help the patient come to an assessment of how much better they are.

The downside of using something like an SF-36 as the basis for scoring improvement in a stereotyped way, possibly using some pre-defined scoring system, is that the SF-36 can only ever be 'the closest standard dataset to an indication of what really matters for that patient'. By definition it cannot be better than sitting down and deciding, after mulling over the SF-36 results, what does really matter to the patient. Surely, the patient is likely to say 'that pretty much figures but actually for me this problem is much more important than that one now that I think about it'. Maybe SF-36 is clever enough to handle that but I doubt it.

This is where my individualised criteria come in - you sit down and agree what is really important for this person at the beginning. It needs to be within reasonable limits but as for lupus I suspect that a short list can be drawn up. You then have an outcome which cannot be charged with being irrelevant to patient needs. But if you do the SF-36 first to get your eye in I have no problem with that - and you still have your data for comparison with other groups.

On a wider issue I note that you suggest SF-36 is good for function. But in the framework I was suggesting it has to fall under number 1 because it is open to reporting bias. Number 1 is allowed to be largely or completely based on functional deficit but number 3 needs to be free of any reporting issues. It has to be what actually happened in terms of functioning - probably by some sort of actimetry. Not that this generates a problem. Using SF-36 function and whatever else as at least a preliminary sorting exercise for 1 still makes sense to me.

A final mischievous thought is that maybe assessments should be done monthly for a year and the time point of the outcome assessment decided by some third party and sealed in a brown envelope at the start (or you might need 12 brown envelopes, 11 saying no and one saying yes). Then neither the therapist nor the patient know which month is the one that matters. That should scotch any chance of patients struggling to get a better score on the assessment day, having rested for a week in preparation.

 

[MeSci]

I am happy to accept that there is value to be found in these scores but I am still wanting to get clear in my head what each component of a composite would really do. So I am not so much disagreeing with anyone as throwing out thoughts about where things do not quite gel for me.

The potential for comparisons with other studies I can see is an advantage, although one might worry about context dependent biases. So gathering an SF-36 dataset might be a good thing for such secondary purposes.

There also seems to be an issue about remembering previous status. Some people here have suggested that it is easier to compare two levels of well being than give an absolute indicator at any one time. (I think the outcome measure has to be a comparison so that is fine from that angle.) But others have suggested that it is easy to forget what you were like at the beginning. What would seem sensible to me would be for the trialist and patient to go through all the issues that impact on the global illness problem, symptomatic and functional and to record them. SF-36 may be a good way to collect those data and if it is done again at the end then you have a pretty good idea of what the comparison is. (Looking back at the old score may help the patient come to an assessment of how much better they are.

The downside of using something like an SF-36 as the basis for scoring improvement in a stereotyped way, possibly using some pre-defined scoring system, is that the SF-36 can only ever be 'the closest standard dataset to an indication of what really matters for that patient'. By definition it cannot be better than sitting down and deciding, after mulling over the SF-36 results, what does really matter to the patient. Surely, the patient is likely to say 'that pretty much figures but actually for me this problem is much more important than that one now that I think about it'. Maybe SF-36 is clever enough to handle that but I doubt it.

This is where my individualised criteria come in - you sit down and agree what is really important for this person at the beginning. It needs to be within reasonable limits but as for lupus I suspect that a short list can be drawn up. You then have an outcome which cannot be charged with being irrelevant to patient needs. But if you do the SF-36 first to get your eye in I have no problem with that - and you still have your data for comparison with other groups.

On a wider issue I note that you suggest SF-36 is good for function. But in the framework I was suggesting it has to fall under number 1 because it is open to reporting bias. Number 1 is allowed to be largely or completely based on functional deficit but number 3 needs to be free of any reporting issues. It has to be what actually happened in terms of functioning - probably by some sort of actimetry. Not that this generates a problem. Using SF-36 function and whatever else as at least a preliminary sorting exercise for 1 still makes sense to me.

A final mischievous thought is that maybe assessments should be done monthly for a year and the time point of the outcome assessment decided by some third party and sealed in a brown envelope at the start (or you might need 12 brown envelopes, 11 saying no and one saying yes). Then neither the therapist nor the patient know which month is the one that matters. That should scotch any chance of patients struggling to get a better score on the assessment day, having rested for a week in preparation.

It would seem a shame not to use every month's data if you have them. Hope I have understood you right - having a bad-brain day.

I agree with the emphasis on what matters for the patient in terms of improvement/non-improvement, but presumably these aspects will need to be relevant to ME/SEID, i.e. be part of the diagnostic criteria used?

When I look at my list of improvements on my leaky-gut diet, I note that some of the problems are not included in diagnostic criteria, and perhaps most people do not have the problems in the first place. However, for myself they do form part of my ME-related pathology; specifically I think that they are related to causative factors arising from abnormalities in gut and immune system. I'm thinking for example of weight and appetite normalisation and clearance of dermatitis.

 

[Bob]

The downside of using something like an SF-36 as the basis for scoring improvement in a stereotyped way, possibly using some pre-defined scoring system, is that the SF-36 can only ever be 'the closest standard dataset to an indication of what really matters for that patient'. By definition it cannot be better than sitting down and deciding, after mulling over the SF-36 results, what does really matter to the patient. Surely, the patient is likely to say 'that pretty much figures but actually for me this problem is much more important than that one now that I think about it'. Maybe SF-36 is clever enough to handle that but I doubt it.

I agree that SF-36 PF is a course instrument. There's not much nuance and not much subtlety about it. I think that's one of its weaknesses. And, as you say, the questions might be unimportant to ME patients.

 

[Bob]

There also seems to be an issue about remembering previous status. Some people here have suggested that it is easier to compare two levels of well being than give an absolute indicator at any one time. (I think the outcome measure has to be a comparison so that is fine from that angle.) But others have suggested that it is easy to forget what you were like at the beginning.

I can't quite follow this - I can't work out if you're suggesting that SF-36 PF is a relative or absolute indicator. I consider it to be an absolute indicator. Here's a discussion we've had about it previously, in case interesting...

SF-36 and subjectivity: try it yourself

Lots of people have suggested that the improvements in the SF-36 Physical Function subscale (and Chalder Fatigue Scale too)for the CBT & GET groups are the result of a change in perception by participants, not a real change in activity levels (or fatigue). I thought I'd see how this might work out in practice for the SF-36 score for me and I think the results are illuminating - others might like to try it too.

How the SF-36 PF scale works:
There are ten questions asking what physical activity people can do. The answers to each question are scored:
Limited a lot=0 points
Limited a little=5 points
Not limited at all=10points

Max 100 points in total.

SF-36 Questions
- vigorous activities such as running
- Moderate activities, such as moving a table, pushing a vacuum cleaner, bowling, or playing golf (yes, weird)
- Lifting or carrying groceries
- Bending, kneeling, or stooping
- climbing several flights of steps
- Climbing one flight of stairs
- walking more than a mile
- Walking several hundred yards
- Walking one hundred yards
- Bathing or dressing yourself

For me, the first thing is that on 8 of these I'm clearly either a 0 (eg walking more than a mile)or a 10 (bending, kneeling).

However, for 'climbing one flight of stair' I would score me as a 5 (limited a little)in that usually I can do this fine but can struggle on bad days of if I've just done something else physical like walking round the house a bit. But maybe after a bit of CBT I'd focus more on what I can do and score a 10 (not limited at all); it wouldn't take a very big shift in perspective. The same applies to one other question where I could also pretty easily upgrade from a 5 to a 10.

Conclusion: I could easily add 10 points to my score just by taking a slightly more upbeat view of things, though it would be very hard to boost my score by more than 10 points, at least without the help of mind-altering drugs. Coincidentally, CBT and GET both came in with SF-36 scores about 10 points higher than the SMC group.

I'd be interested to know how this would work for other people. I'm sure most people won't want to discuss personal details of how their illness effects them, but it would be useful to know a likely 'change in score' due to a more upbeat perspective.

 

[Jonathan Edwards]

It would seem a shame not to use every month's data if you have them. Hope I have understood you right - having a bad-brain day.

They could still be made use of for secondary analyses.

 

[A.B.]

As mild to moderately affected patient I would get a very high score on the PF-36 physical functioning scale. I'm physically capable of all these things (some might be uncomfortable). The issue is lack of energy over time (stamina) and feeling sick after doing too much which the PF-36 cannot capture at all.

Edit: I meant high.

 

[WillowJ]

I'm not familiar with many other self-report scales,

for fatigue alone, I found a review paper, but haven't yet felt up to getting the full text.

I thought this was significant from the abstract:

Only four measures (BFI, FSS, FSI, and MAF) demonstrated the ability to detect change over time.

 

[Bob]

As mild to moderately affected patient I would get a very low score on the PF-36 physical functioning scale. I'm physically capable of all these things (some might be uncomfortable). The issue is lack of energy over time (stamina) and feeling sick after doing too much which the PF-36 cannot capture at all.

The scale doesn't ask if you are capable of carrying out those activities, but it allows you to indicate if you are limited in any of those activities. If you can't do them easily, or repeatedly, or without discomfort, or without them making you sick, then I'd interpret that as limited or very limited.

 

[WillowJ]

The scale allows you to indicate if you are limited in any of those activities. If you can't do them easily, or repeatedly, or without discomfort, or without them making you sick, then I'd interpret that as limited.

Or as not at all, depending on how severe the problem is. (I probably can literally use 1/2 to 1 flight of stairs with great difficulty and lots of rest stops, but I don't because I'd be crippled for at least a week after.... it's not a fair trade for whatever is at the end of the stairs--if there is no elevator it is effectively inaccessible to me--so I mark it as 0, I cannot)

 

[Jonathan Edwards]

I can't quite follow this - I can't work out if you're suggesting that SF-36 PF is a relative or absolute indicator. I consider it to be an absolute indicator. Here's a discussion we've had about it previously, in case interesting...

All outcome measures in trials are going to be changes in some measurement attributable to a change in treatment (usually initiation of treatment but not always). I agree that a single SF-36 record gives an absolute measure but in this situation it is being used to derive a change from baseline.

But I guess 'absolute' is a can of worms here, as others have been saying. Limited a lot in climbing three flights of stairs might mean very different things to different people. I used to be able to do six flights of stairs at a run two steps at a time in Hillingdon Hospital when the lift was broken. No way would I do more than one flight like that now, but I do not see myself as limited, just a bit more dignified.

 

[Ellkaye]

my view on VO2 max testing :

charting consecutive (or single) VO2 max test scores is probably the best measure of improvement but only if patients are improving very significantly and sustainably after a confirmed and safe period of time when they know their bodies are strong again, thus confirming improvement beyond any reasonable doubt from any kind of treatment received. Only snag is you need before and after measurements to see if any such targeted pharmacological treatment is working, and below a certain function % I reckon it can be inappropriate to do these tests for obvious reasons..

it totally and inexcusably inappropriate for those who are not improving significantly to do this test, for obvious reasons as I say, unless they need to prove disability I guess. But again what a ghastly way to have to do so given the post exertional malaise they would endure. But I guess some people just don't have a choice or any other way to prove how sick and incapacitated they are with people not believing them given all the bad media and bad science out there. In my book it's not worth it and potentially dangerous and wouldn't do it personally below a baseline of 60% function on the Bell disability scale. No way. Hats off and full respect to those who do as they have no other choice though.

my VO2 max scores three years ago were around 26-27 so in the very lowest category for my age, but I was at 60% function on the Bell scale (so just on the borderline in my view for it being ok to do this otherwise unwarranted test). But there was no real significant day 1 or day 2 change. Score was more or less the same. I went in there thinking there would be a difference so as to prove it to myself as I had been reading about reports of significant day 2 changes. But the scores just came out the same on both days. In retrospect a bit of a waste of time I thought then initially but I m interested to know what my score is now three years on I must admit.... Perhaps depends on how sick you are, if you are below 50% then you see the day 1 day 2 drop.... In which case as I say I reckon you need to have some reason to have to do them and put yourself through it such as consenting to be in a clinical or longitudinal study, or to prove disability but at a risk if you must, or doing it for the greater good! By the way I can't believe Dr Oz spoke of this as a womans disease with MD and PHD Lipkin sitting right next to him and not saying anything..! I really was left scratching my head...
Then again this illness has a history of unfortunate facts attached to it. Three times less people (with all their thousands of cytokines and chemokines after any old virus hitting the immune pathways) actually have this disease actually triggered than is reported and the best science and research never gets followed up and everyone just gets clumped together until overlaps are made to be found from many groups for that window of time when it is possible to see immune activation... ! Mmm Hum... Ah ha....! Smart science ! Wow ! Now you see it now you don't, now you do, now you don't, then you do, then you don't....... ! The three year thing too...
I don't know who is worse. Virus hunters or Psychiatrists ! Or maybe a slow shell game before the last shell comes off with complete disregard for each other, but we both do believe you, really, you are really sick, all of you! !! Hit n run run run ! We'll hit all of you pateints for four after four after four, just to stop you real ones hitting us back with the odd 6 every now n then (three times less that is!). Sorry my American friends if you are not versed in the game of cricket but you may get the idea anyway. Not that much difference between and 4 and a 6 is there! You still use a bat and ball in both cases ! Hell the chemokine cytokine sound the bat makes is the same too be it a 4 or a 6! We don't need to practice our 6's when we can hit so many 4's !!!!!!!

And if that s not bad enough you've got jesters and jokers dressed up around the pitch catching the ball and saying they know what they're doing with it when in fact they haven't got a damn clue or think they do or are being left to think that they do through the false sense of power a funded study gives them ! what a CIRCUS !!! Fall guys !!!!

When will it all stop?!
Do they know it has stopped/is stopping.....?



With all that said, I am due to go to do my VO2 max tests again to compare them to three years ago. I am not worse than what I was three years ago (when I was at 60% remember). That's all I'll say for now........!


Remember each case is different and any decisions must be taken together with ones physicians.

 

[user9876]

All outcome measures in trials are going to be changes in some measurement attributable to a change in treatment (usually initiation of treatment but not always). I agree that a single SF-36 record gives an absolute measure but in this situation it is being used to derive a change from baseline.

But I guess 'absolute' is a can of worms here, as others have been saying. Limited a lot in climbing three flights of stairs might mean very different things to different people. I used to be able to do six flights of stairs at a run two steps at a time in Hillingdon Hospital when the lift was broken. No way would I do more than one flight like that now, but I do not see myself as limited, just a bit more dignified.

I think one of the big problems with the SF-36 scale is it doesn't relate to what people actually do but what they perceive they can do or how easy it is for them to do it. Its one of the reasons its a particularly poor scale for things like PACE where the treatment is trying to change perception of illness.

I see a big advantage in recording what people actually do in a day. Where people are struggling with activities of daily living these can be a good measure. For more mildly affected patients whose threshold is above this it may not be the case.

 

[duncan]

Every time I go to the NIH, I am requested to fill out an SF-36. Each time I do, I cringe because I know how vague and general the questions are, and I know how my answers may be misconstrued.

Same holds true for parts of neuro-cog evaluations. Here I think the problems are potentially more egregious, and I know testers can manipulate some data to suit their purposes.

I expressed my concerns about both, and I feel confident steps have been taken to change formats for both mechanisms.

 

[Marco]

The following study suggests that there is little to choose between (subjective) self-reported and (objective) performance based measures of physical function. At least in hip fracture patients. So unless you suspect that there's something inherent in ME/CFS patients or the type of therapy (ahem) that would preclude using subjective measures?

Performance-based or self-report measures of physical function: which should be used in clinical trials of hip fracture patients?

CONCLUSIONS:

Findings reveal that the validity, sensitivity, and responsiveness of self-report measures of physical function are comparable to performance-based measures in a sample of patients followed after fracturing a hip. From a psychometric perspective, either type of functional measure would be suitable for use in clinical trials where improvement in function is an endpoint of interest. The selection of the most appropriate type of functional measure as the primary endpoint for a clinical trial will depend on other factors, such as the measure's feasibility or the strength of the association between the hypothesized mechanism of action of the study intervention and a functional outcome measure.

http://www.ncbi.nlm.nih.gov/pubmed/18996244

 

[MeSci]

The following study suggests that there is little to choose between (subjective) self-reported and (objective) performance based measures of physical function. At least in hip fracture patients. So unless you suspect that there's something inherent in ME/CFS patients or the type of therapy (ahem) that would preclude using subjective measures?

Performance-based or self-report measures of physical function: which should be used in clinical trials of hip fracture patients?

CONCLUSIONS:

Findings reveal that the validity, sensitivity, and responsiveness of self-report measures of physical function are comparable to performance-based measures in a sample of patients followed after fracturing a hip. From a psychometric perspective, either type of functional measure would be suitable for use in clinical trials where improvement in function is an endpoint of interest. The selection of the most appropriate type of functional measure as the primary endpoint for a clinical trial will depend on other factors, such as the measure's feasibility or the strength of the association between the hypothesized mechanism of action of the study intervention and a functional outcome measure.

http://www.ncbi.nlm.nih.gov/pubmed/18996244

I would think that outcomes relating to hip fracture are much easier to define and measure, both objectively and subjectively, than those relating to ME, which is much more complex.

 

[Marco]

I would think that outcomes relating to hip fracture are much easier to define and measure, both objectively and subjectively, than those relating to ME, which is much more complex.

Outcomes relating to the physical improvment in the fracture are more easily defined and measured (X-rays etc) but I don't see why physical function would be any less subjective after all you can develop kinesiophobia after a fracture?

The point being (for me) is that there's no a priori reason to assume that self report measures are any more unsuitable for ME/CFS unless you believe that symptoms/deficits in physical function are exaggerated or that the therapy modulates the reporting irrespective of the disease process.

I get the feeling that we're dismissing subjective measure just because they were inappropriate for use in behavioural trials. They seem to be well accepted elsewhere.

 

[MeSci]

Outcomes relating to the physical improvment in the fracture are more easily defined and measured (X-rays etc) but I don't see why physical function would be any less subjective after all you can develop kinesiophobia after a fracture?

The point being (for me) is that there's no a priori reason to assume that self report measures are any more unsuitable for ME/CFS unless you believe that symptoms/deficits in physical function are exaggerated or that the therapy modulates the reporting irrespective of the disease process.

I get the feeling that we're dismissing subjective measure just because they were inappropriate for use in behavioural trials. They seem to be well accepted elsewhere.

I don't think that subjective measures are being generally dismissed. I got the impression that we were examining the different kinds of measures, looking at their strengths and weaknesses.

I'm sceptical of the term 'kinesiophobia'. Studies I have seen where it has been used have appeared very dubious to me, with obvious alternative explanations that have not been ruled out, not least the fact that patients have learned that certain actions worsen their condition.

Reminds me of when hospital staff have tried to get me to do things I could strongly sense were unwise/inappropriate.

Example 1. A muscle had been removed from my foot. The wound felt very tight, as though it would come open if I put any weight on it. Staff insisted that I put weight on it, despite my protestations. Wound came open, became infected and led to further time in hospital and a very prominent scar.

Example 2. I was extremely tired and sleeping a lot following an overdose. I felt the need for this sleep. I was receiving kidney dialysis. A nurse insisted that I get out of bed, calling me a 'lazy cow' (his charming term for kinesiophobia, perhaps?). Sat in chair, legs swelled up like balloon-sausages, had to be helped back onto bed as could not bend knees and was in considerable pain.

I am sure there are some examples where patients are in fact excessively fearful of movement, but I am equally sure that patients usually perceive their capabilities correctly, but health staff and researchers fail to respect this.

 

[Jonathan Edwards]

The following study suggests that there is little to choose between (subjective) self-reported and (objective) performance based measures of physical function. At least in hip fracture patients. So unless you suspect that there's something inherent in ME/CFS patients or the type of therapy (ahem) that would preclude using subjective measures?

Performance-based or self-report measures of physical function: which should be used in clinical trials of hip fracture patients?

CONCLUSIONS:

Findings reveal that the validity, sensitivity, and responsiveness of self-report measures of physical function are comparable to performance-based measures in a sample of patients followed after fracturing a hip. From a psychometric perspective, either type of functional measure would be suitable for use in clinical trials where improvement in function is an endpoint of interest. The selection of the most appropriate type of functional measure as the primary endpoint for a clinical trial will depend on other factors, such as the measure's feasibility or the strength of the association between the hypothesized mechanism of action of the study intervention and a functional outcome measure.

http://www.ncbi.nlm.nih.gov/pubmed/18996244

Marco; for a start I find this abstract completely incomprehensible. I can get no feel for what any of the measures are telling us because there are no actual data given. That to me is always a sign of phoney science. But maybe the more important point is that there is no trial here. There is no source of bias to come under that wide umbrella we call 'placebo effect'. Patients were not thinking they might have had a good treatment or a dummy.

And as MedSci points out function after hip fracture is a doddle in comparison to ME. Either you can walk this fast or that fast or not at all. All scores are likely to correlate very well - and as said at first I can get no idea of just how well they correlate. They don't actually say what they are testing other than some jargon. Did all the assessments rank the patients in exactly the same order for instance?

Outcomes relating to the physical improvment in the fracture are more easily defined and measured (X-rays etc) but I don't see why physical function would be any less subjective after all you can develop kinesiophobia after a fracture?

I think it is important to be clear what we are calling subjective. In the context of trials it means open to reporting bias due to the psychological context of being on a treatment (placebo effect in several of its forms). If someone cannot walk because they are terrified of walking that is not subjective in this context. Subjectivity is here the potential for discrepancy between report and reality.

The point being (for me) is that there's no a priori reason to assume that self report measures are any more unsuitable for ME/CFS unless you believe that symptoms/deficits in physical function are exaggerated or that the therapy modulates the reporting irrespective of the disease process.

There is nothing special about ME here. The same worry applies to RA, so we bin any trials in RA that are unblinded and use subjective functional end points - which includes all the old physio trials.

I get the feeling that we're dismissing subjective measure just because they were inappropriate for use in behavioural trials. They seem to be well accepted elsewhere.

I am dismissing the sole use of subjective measures in unblinded trials because that is what is standard in other branches of medicine, nothing to do with behavioural trials. Such usage is completely unaccepted elsewhere in that sense. Subjective measures (open to reporting bias) can be used in blinded trials perfectly well and are the standard endpoint for analgesic studies, but they are no good if the patient knows which treatment they are on, whatever the disease.

 

[Marco]

Marco; for a start I find this abstract completely incomprehensible. I can get no feel for what any of the measures are telling us because there are no actual data given. That to me is always a sign of phoney science. But maybe the more important point is that there is no trial here. There is no source of bias to come under that wide umbrella we call 'placebo effect'. Patients were not thinking they might have had a good treatment or a dummy.

Hard to tell from the abstract. I assume they correlate scores from the various measures with patients' Global Asessment of Improvement which of course is also 'subjective'. The point I was trying to make was that self report appears to be as reliable as 'objective' measures when there's no reason to suspect bias.

And as MedSci points out function after hip fracture is a doddle in comparison to ME. Either you can walk this fast or that fast or not at all.

Not necessarily :

http://www.ncbi.nlm.nih.gov/pubmed/21680032

I think it is important to be clear what we are calling subjective. In the context of trials it means open to reporting bias due to the psychological context of being on a treatment (placebo effect in several of its forms). If someone cannot walk because they are terrified of walking that is not subjective in this context. Subjectivity is here the potential for discrepancy between report and reality.

Fair enough.

I am dismissing the sole use of subjective measures in unblinded trials because that is what is standard in other branches of medicine, nothing to do with behavioural trials. Such usage is completely unaccepted elsewhere in that sense. Subjective measures (open to reporting bias) can be used in blinded trials perfectly well and are the standard endpoint for analgesic studies, but they are no good if the patient knows which treatment they are on, whatever the disease.

Good. So the issue isn't with the use of subjective measures but with blinding.

 

[MeSci]

http://www.ncbi.nlm.nih.gov/pubmed/21680032

This refers to the 'Tampa Scale for Kinesiophobia'.

This gave me a moment. I did some searching and found this document about it. It starts:

By use of this questionnaire, we would like to examine how you feel about your complaints and how you experience them.

You are asked to indicate whether or not you agree with each of the statements listed. It is of prime importance that you only use your own opinion and thought; what others might think is not of interest here.

We do not attend to assess your medical knowledge either. The questionnaire is just about the way you experience your complaints.

The questions remind me of some others I have seen relating to both ME and depression, and frankly I don't see how the answers will be of any use in ascertaining whether someone's fears are justified or not. It seems to me that the patient's answers will just be pitted against the physician's/researcher's opinions, and my own experience in this regard is that my own perception has often been more accurate than that of physicians.

EDIT

and I am concerned to see KDM involved in this kind of thing.