Impact of intraindividual pain variability on functional pain outcomes among adults with chronic pain: an ecological momentary assessment study.

Chronic pain is a significant public health problem linked to notable functional impairment and economic burden. Despite considerable research attention, chronic pain treatments only yield small to medium sized effects for pain complaints. Better understanding the pain experience may help improve treatment outcomes for pain. Specifically, intraindividual variation in pain intensity represents a potentially important avenue that captures the dynamic nature of pain and may improve overall understanding of pain. Limited work has examined metrics of intraindividual pain variation across chronic pain populations, but no work has examined how these metrics are associated with pain functional outcomes (pain-related disability, negative affect, and activity avoidance). Therefore, the current study utilized ecological momentary assessment to assess pain intensity, pain-related disability, negative affect, and activity avoidance, 5 times a day for 7 days, among 48 adults with chronic pain. Results suggested that pain instability metrics (e.g., intraindividual standard deviation) were associated with pain-related activity avoidance, while dynamic metrics of variability (e.g. % of time in high pain) were directly associated with pain-related disability and negative affect. Results from the current study have important clinical implications that can be applied to the assessment of pain to guide further treatment planning. Contextualizing pain as a dynamic experience that can be captured via intensive self-report assessment may improve overall intervention outcomes.