Identifying important outcome domains for chronic pain clinical trials: an IMMPACT survey of people with pain.

This two-phase study was conducted to identify relevant domains of patient-reported outcomes from the perspective of people who experience chronic pain. In Phase 1, focus groups were conducted to generate a pool of patient outcome-related domains and their components. The results of the focus groups identified 19 aspects of their lives that were significantly impacted by the presence of their symptoms and for which improvements were important criteria they would use in evaluating the effectiveness of any treatment. Phase 2 was conducted to examine the importance and relevance of domains identified from a much larger and diverse sample of people with chronic pain. A survey was developed and posted on the American Chronic Pain Association website. Participants were asked to rate the importance of each item or domain identified by the focus groups on a scale of 0 to10 (i.e., 0="not at all important" and 10="extremely important"). The survey was completed by 959 individuals. The results indicate that all 19 aspects of daily life derived from the focus groups were considered important with a majority of respondents indicating a score of 8 or greater. In addition to pain reduction, the most important aspects were enjoyment of life, emotional well-being, fatigue, weakness, and sleep-related problems. Chronic pain clearly impacts health-related quality of life. The results of the two phases of the study indicate that people with chronic pain consider functioning and well-being as important areas affected by the presence of symptoms and as appropriate targets of treatment. These multiple outcomes should be considered when evaluating the efficacy and effectiveness of chronic pain treatments.