Underestimating or Overestimating Improvement in Pain on a Smartphone Pain App: Role of Disability, Negative Affect, and Pain App Engagement

Abstract

Clinicians often ask people with chronic pain about their perceived benefit from interventions designed to improve their pain. The aim of this study is to identify factors that contribute to underestimating or overestimating perceived changes in daily pain intensity over a month of daily assessments. We examined data from individuals with chronic pain who provided at least 28 daily assessments using a pain app as secondary analyses. Participants provided baseline demographic information and completed questionnaires assessing pain, activity interference, mood, pain disability, and catastrophizing. Using the pain app, they entered daily ratings of pain (0 = none, 10 = worst pain possible) and impressions of perceived day-to-day change (0 = better, 5 = same, and 10 = worse). Two hundred fifty-two (N = 252) subjects with chronic pain met the inclusion criteria of completing at least 28 daily assessments. Those who underestimated their improvement tended to have higher pain intensity at baseline (P < .001), reported greater activity interference and disability (P < .001), and were prone to greater catastrophizing and anxiety and depression (P < .01). People who were more accurate in assessing their improvement engaged less with the app with fewer 2-way messages compared with those who either underestimated or overestimated their improvement and who had more 2-way messaging (P < .05). This longitudinal study suggests that those who report greater levels of catastrophizing and anxiety and depression are more likely to underestimate any improvements in their pain over time but seem to engage more with a pain app. Future research will help in our understanding of what magnitude of perceived change in pain ratings is clinically meaningful. PerspectiveThose who report greater levels of pain, disability, anxiety, depression, and catastrophizing are most prone to underestimate improvements of their pain over time.