Patterns of pain-related activity: replicability, treatment-related changes, and relationship to functioning.

Changes in activity patterns frequently accompany the experience of chronic pain. Two activity patterns, avoidance and overdoing, are hypothesized to contribute to the development of ongoing pain and pain-related disability, while activity pacing is frequently introduced to enhance pain management and functioning. Two studies were conducted to assess whether reliable subgroups with differing activity patterns could be identified in different pain populations and to evaluate changes in these subgroups after a group format, pain management program. In study 1, individuals with ongoing pain being assessed for treatment at 2 different tertiary care pain centres completed a measure of pain-related activity. Separate cluster analyses of these samples produced highly similar cluster solutions. For each sample, a 2-cluster solution was obtained with clusters corresponding to the activity patterns described by the avoidance-endurance model of pain. In study 2, a subset of individuals completing a 12-session, group format, pain management program completed measures of pain-related activity, pain intensity, and physical and psychological functioning at the beginning and end of the program. At the conclusion of the program, 4 clusters of pain-related activity were identified. Individuals who used high levels of activity pacing and low levels of avoidance consistently reported significantly better functioning relative to all other individuals. Observed changes in activity patterns from pre-treatment to post-treatment suggested that decreasing the association between activity pacing and avoidance was associated with better functioning. These results have implications for both the assessment of activity pacing and for its use as an intervention in the management of ongoing pain.