I am stumped. Here is a common clinical quandary – one of the most important outcomes from pain management is to increase participation in daily activity (occupation), yet the measures we use just don’t quite cut it for me. Here’s a couple of examples: in the IMMPACT recommendations from 2008 (in the paper I’ve cited below and from the one I cited earlier this week) two ‘disability’ measures are suggested as a way to assess disability. One is the ‘Interference’ subscale from the Multidimensional Pain Inventory, and the other is the Pain Disability Index. Both of these have sound psychometric properties, have been used for a long time in pain management research and clinical use – but both of them have problems.
The problems are about floor and ceiling effects – so they don’t measure very high and very low levels of disability, both are not especially sensitive to small amounts of change so a person needs to make quite significant changes for these measures to capture them, and most importantly to me – they give each domain of functioning equal weighting. As well – neither of these measure participation in our social world particularly well – what about being an effective parent or being able to go shopping or go to a restaurant or catch a bus? And how were these measures developed? Were people with pain asked to generate these domains or were they derived from what clinicians and researchers believe is important.
As I mentioned in my previous post on what people with pain think is important, I don’t believe the ‘client-focused’ aspects of these measures is especially well-developed. In other words, the measures that are currently available don’t really represent individual’s ability to do what matters in their lives. And of course these measures are somewhat culturally-bound.
This area of health measurement is something that needs more attention – how to accurately measure, across patient groups and diagnoses, the degree to which pain interferes with doing things. There’s a tussle between focusing on the components: can the person move each limb, walk, bend, reach and so on; and the larger ‘whole’ of being able to get around the community, have good relationships, manage home life, go to work.
I don’t know what the answer is, but I am looking! I think there is merit in working towards a reasonably short questionnaire (because seriously, we can give people SO many to complete!) that involves people ranking the importance of an activity as well as their perception of how much pain interferes with being able to do it.
Now before the occupational therapists remind me of COPM (the Canadian Occupational Performance Measure) I need to remind them that this measure takes time and is very individual. This isn’t quite as helpful in either a clinical or research setting as a pen and paper tool because it does require an occupational therapist to administer it, and I’m not entirely certain of the inter-rater reliability of it. To me, a measure that needs a clinician to facilitate answering it introduces another set of variables that can’t be easily controlled for, making analysis quite difficult especially in a clinical setting rather than a research setting. And I do live in a real world where there are three occupational therapists in the Pain Management Centre, and all with quite different ways of eliciting information from people. Not to mention that one of the reasons I’m currently looking at these measures is the need to find something that can be introduced to another Pain Management Centre so we can compare results!
Whew! Got that off my chest!
Where to from here?
I’ve a suspicion that it might be possible to work with the findings of the IMMPACT group of Turk, Dworkin, Revicki et al. (2008). Maybe if we attended to the concerns about function and participation that people with chronic pain want addressed, and started to develop a measure based on their needs, we might find a way to really monitor useful outcomes.
I think it will take some time – and I hope that people with a strong interest in participation and occupation (ie my occupational therapy colleagues) will get involved in this, along with the physiotherapists and psychologists.
The measure needs to incorporate how well the person with pain is able to get involved in the community, as well as his or her individual activities. We need to move beyond ‘can you walk?’ and look much more at ‘can you walk where you want to go?’, and we need to recognise that not all domains of functioning are equal.
How this is done is a methodological issue with loads of challenges – but it’s so important that I’m concerned that it hasn’t been looked at before. What a challenge for us as clinicians!
Dworkin, R., Turk, D., Farrar, J., Haythornthwaite, J., Jensen, M., Katz, N., Kerns, R., Stucki, G., Allen, R., & Bellamy, N. (2005). Core outcome measures for chronic pain clinical trials: IMMPACT recommendations Pain, 113 (1-2), 9-19 DOI: 10.1016/j.pain.2004.09.012