Background & Aims
Treatment expectations (TEs) influence patient outcomes in clinical practice and could modify chronic pain treatment responses. However, evidence is mainly derived from adult studies focused on musculoskeletal pain and pharmacological and a few alternative interventions (e.g., acupuncture). Given the suggested powerful placebo analgesia in children and the robust evidence for psychological interventions in youth with chronic pain, this study explored TEs in clinical trials of digital cognitive-behavioral therapy (CBT) in youth with chronic pain. We aimed to evaluate the direct impact (i.e. main effect) of TEs on pain outcomes over time regardless of treatment assignment, and whether TEs modified treatment efficacy of CBT relative to education control (i.e. moderation effect). Informed by the placebo mechanism, we hypothesized that higher TEs predicted greater improvement in outcomes over time, and in youth with higher TEs, the treatment efficacy of CBT compared to control was reduced.
Methods
Data from two randomized controlled trials of digital CBT for youth with chronic pain were analyzed, including predominantly White youth with primary chronic pain (Sample 1, n=273, ages 11-17, 75% female) and youth with sickle cell pain who were predominantly Black (Sample 2, n=111, ages 12-18, 59% female). TEs were defined in three ways: 1) a global item measuring the overall belief in the intervention’s (i.e., digital CBT) usefulness for youth with chronic pain, 2) domain-specific items measuring beliefs about how the intervention might reduce pain, increase activities, boost happiness, and improve pain coping, and 3) a multidimensional scale measuring perceived intervention benefits across different life domains. Linear mixed effect regression models examined the main effect of baseline TEs in improving pain-related outcomes at 2 and 6 months, as well as the moderation effect of TEs in CBT efficacy (relative to education control).
Results
In Sample 1, consistent with hypotheses, higher TEs predicted greater improvement in general and pain-specific anxiety, as well as greater improvement in sleep quality, with most of the significant main effects observed for the global TEs and outcomes at 6 months. Also as expected, higher TEs were associated with reduced digital CBT efficacy (relative to education control) in improving depressive and anxiety symptoms at 6 months, with the largest moderation effects seen for the multidimensional TEs. In Sample 2, hypotheses were partially supported: higher TEs predicted greater improvement in negative thinking and mobility at 2 and 6-months, but less improvement in pain intensity and pain coping at 2 months and mood at 6 months; most of the significant main effects were seen for the global and multidimensional TE measures. For moderation, higher multidimensional TEs were associated with greater CBT efficacy (relative to education control) in improving mood and mobility at 2-months.
Conclusions
In this secondary analysis of clinical trials of digital CBT for youth with chronic pain, the hypothesized main and moderation effects of TEs were mainly supported in White youth with chronic primary pain, but refuted or at least inconsistent in Black youth with sickle cell pain. Findings highlight the need to explore the meaning of TEs in youth, refine and standardize the measurement of TEs, and consider population characteristics in understanding the role of TEs in chronic pain treatment responses.
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Presenting Author
Rui Li
Poster Authors
Rui Li
PhD
Center for Child Health, Behavior and Development, Seattle Children’s Research Institute, Seattle, Washington, USA
Lead Author
Kavin Srinakarin
BS
Center for Child Health, Behavior and Development, Seattle Children’s Research Institute, Seattle, Washington, USA
Lead Author
Rocío de la Vega
PhD
Facultad de Psicología y Logopedia, Universidad de Málaga, Málaga, Spain
Lead Author
Tonya M Palermo
PhD
Center for Child Health, Behavior and Development, Seattle Children’s Research Institute, Seattle, Washington, USA
Lead Author
Topics
- Evidence, Clinical Trials, Systematic Review, Guidelines, and Implementation Science