The impact of pain management on quality of life


ResearchBlogging.org

What exactly is quality of life? And what is pain management? This article, presented at a 2002 Roundtable on ‘The role of coxibs in successful pain management’ is written by a medical researcher, which should give you a bit of a clue about how pain management is defined for the purpose of this paper (i.e. pain control). Much of the discussion about quality of life measures, however, is useful, and the article itself is reasonably short – and it talks the language of doctors, which I thought gives an interesting slant.

Firstly, the point is made that quality of life involves assessment over multiple dimensions, with the World Health Organisation’s ‘Domains and factors of quality of life’ being used as an example of the domains that can be considered. For those who haven’t reviewed this recently, there are six domains:
1. Physical
2. Psychological
3. Level of independence
4. Social relationships
5. Environmental health
6. Spirituality
and a final ‘general’ facet that evaluates ‘overall perceptions of health and quality of life’.  This link to WHOQOL leads directly to the Seattle Quality of Life Group website.

The point is made that pain affects cognitive, motivational, affective, behavioural and physical components, and quality of life has a similarly all-encompassing nature. Katz points out that ‘quality of life … can be defined as an individual’s ability to perform a range of roles in society and to reach an acceptable level of satisfaction from functionoing in those roles’, but at the same time recognising that quality of life research is relatively new, and the effects of pain on quality of life is only just beginning to be investigated.

When we’re choosing any assessment tool, there are some practical things to consider – quite apart from the psychometric properties of the instruments we may think of. Katz nicely identifies some considerations:
1. Which is more applicable – a disease-specific or generic instrument? He identifies that there are both advantages in specific measures (for example, able to detect more subtle change) as well as disadvantages (difficulty comparing across patient groups). The SF-36 (Medical Outcomes Study Short Form 36) is suggested as a general health status measure that combines the ‘best’ of both worlds.
2. What dimensions of quality of life need to be measured? Katz acknowledges that quality of life measures are multi-dimensional since ‘an instrument that does not include several dimensions will make it impossible to determine the nature of a score change’. The areas of physical, psychological, social, somatic, and spiritual are thought to be important, and again the SF-36 is identified as a key contender because of the breadth of dimensions included.
3. How much responder burden is acceptable? This refers to the amount of work needed to complete the questionnaires – an important consideration when we recognise that many people don’t like paperwork, or have relatively low reading levels.
4. What administrative issues need to be considered? Ahhh, now that’s an excellent point! A very comprehensive database that I know of has been abandoned from time to time because of difficulty obtaining clerical time to score and enter questionnaires, and in the mists of time, some of the original scoring ‘rules’ have been lost… Questionnaires used in pain outcome measurement need to be applied at least twice, more appropriately three or four times – and ‘compliance’ or the number of people who complete all of the measures all of the time reduces over time…
5. Has the instrument been validated, and is it reliable? Well, this goes without saying… and should be a ‘given’ for people working in the area of pain management.

There are a number of issues that this paper does not cover well.
Firstly, there is an assumption that if quality of life is reduced when pain is experienced, an individual’s quality of life should improve simply by reducing pain intensity. While this intuitively makes sense, it assumes that pain intensity alone is responsible for loss of quality of life. Reports of pain intensity are influenced by things like psychological distress, fear of injury, fear of being out of control, low mood, health anxiety and so on (e.g. Severeijns, Vlaeyen, van den Hout & Weber, 2001). When analgesia is used, while it may reduce pain intensity it may not address underlying issues such as low mood, health anxiety, and most especially fear of injury. The latter is one reason some patients tell me they don’t want to take medication, because it ‘masks’ pain!

Katz suggests that ‘analgesic agents should be compared … incorporating the use of symptom distress scales, which may be the most sensitive way of discriminating among analgesics in effects of quality of life’. I suggest that distress scales may not be the most appropriate measure of effectiveness in quality of life, and in fact changes across several domains such as Physical, Psychological, Level of Independence, and Social Relationships should be observed before an intervention should be considered ‘successful’.

Another issue is that although Katz indicates that taking repeated measures is important, he makes little mention of the need for longer-term followup. At least part of the initial response from any intervention is likely to be due to the ‘meaning response’, or expectancies or placebo response that people have simply from having been given a treatment. As a result, it’s important to measure changes in quality of life (and any other outcome measure) some months or even years later after the treatment is first initiated. The risk otherwise is that an initial lifting of mood, sense of hope, even physiological changes secondary to placebo can subside over time – and in the end, it’s the effects that are sustained that are important.

However, it’s difficult to argue with Katz on this: quality of life measures should be included as a key variable in future pharmacological research. Personally, I think it should be included as an outcome measurement of any pain management intervention.

For further information on a broader range of outcome measures that are being considered for pain management, this article by Dworkin and colleagues provides some insights into the areas that the IMMPACT group recommend: (1) pain; (2) physical functioning; (3) emotional functioning; (4) participant ratings of improvement and satisfaction with treatment; (5) symptoms and adverse events; and (6) participant disposition.  Worth a read – and they’re continuing to publish more on this area.

Katz, N. (2002). The Impact of Pain Management
on Quality of Life. Journal of Pain and Symptom Management, 24(1S), S38-S47.

Severeijns, R., Vlaeyen, JWS., van den Hout MA., & Weber, JWA., (2001)Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment. The Clinical journal of pain vol. 17, no2, pp. 165-172

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