Avoid or engage? Outcomes of graded exposure in youth with chronic pain using a sequential replicated single-case randomized design

Abstract

Pain-related fear is typically associated with avoidance behavior and pain-related disability in youth with chronic pain. Youth with elevated pain-related fear have attenuated treatment responses; thus, targeted treatment is highly warranted. Evidence supporting graded in vivo exposure treatment (GET) for adults with chronic pain is considerable, but just emerging for youth. The current investigation represents the first sequential replicated and randomized single-case experimental phase design with multiple measures evaluating GET for youth with chronic pain, entitled GET Living. A cohort of 27 youth (81% female) with mixed chronic pain completed GET Living. For each participant, a no-treatment randomized baseline period was compared with GET Living and 3- and 6-month follow-ups. Daily changes in primary outcomes fear and avoidance and secondary outcomes pain catastrophizing, pain intensity, and pain acceptance were assessed using electronic diaries and subjected to descriptive and model-based inference analyses. Based on individual effect size calculations, a third of participants significantly improved by the end of treatment on fear, avoidance, and pain acceptance. By follow-up, over 80% of participants had improved across all primary and secondary outcomes. Model-based inference analysis results to examine the series of replicated cases were generally consistent. Improvements during GET Living was superior to the no-treatment randomized baseline period for avoidance, pain acceptance, and pain intensity, whereas fear and pain catastrophizing did not improve. All 5 outcomes emerged as significantly improved at 3- and 6-month follow-ups. The results of this replicated single-case experimental phase design support the effectiveness of graded exposure for youth with chronic pain and elevated pain-related fear avoidance.

Conflict of interest statement

Disclosures: This investigation was supported by American Pain Society/Sharon S. Keller Chronic Pain Research Grant, Deborah Munroe Noonan Memorial Research Fund, and NIAMS/R21 AR072921 awarded to LES). Johan W.S. Vlaeyen is supported by the research program “From acute aversive sensations to chronic bodily symptoms”, a long-term structural Methusalem funding (METH/15/011) by the Flemish government, Belgium. There are no conflicts of interest to report.

Figures

Figure 1.. GET Living phases and assessments.

Enrollment begins at the Baseline assessment with electronic diary surveys occurring daily until Discharge. It is hypothesized that daily diary reports will be stable during the randomized baseline period (7–25 days). During Education (Phase 1–3 of GET Living) it is hypothesized that daily diary reports will remain relatively stable with significant improvements (decreased fear, avoidance, pain, catastrophizing; increased acceptance [increase not depicted for simplicity]) observed during Exposure (Phase 4 of GET Living). It is hypothesized that 7-day daily diary reports at 3-month and 6-month follow-up will be stable and reflect sustained improvements in outcomes.

Figure 2.

CONSORT Flowchart of Enrollment.

Figure 3.. Raw data from Treatment Responder.

The raw daily diary data across outcomes and timepoints for a Treatment Responder is depicted for visual inspection and descriptive analysis. Via visual inspection, the baseline values across outcomes is relatively stable with modest improvements observed during the Education phase of treatment. The slope of improvement was much steeper during the Exposure phase, with stable improvement at 3-month follow-up, with re-emergence of pain related distress at 6-month follow-up. Comparing baseline to end of treatment (means phase A minus means phase B), Fear=1.04 (0.66), Avoidance=2.86 (0.90), and Acceptance=1.78 (0.84) improved with medium individual effects. Comparing baseline to 3-month follow-up (means phase A minus means phase C), Fear=5.01 (1.0), Avoidance=8.75 (1.0), Catastrophizing=3.84 (1.0), Pain=5.88 (1.0), and Acceptance=6.57 (1.0) improved with large individual effects. Interestingly at 6-month follow-up when compared baseline (means phase A-= minus means phase D), Avoidance=2.29 (1.0), Pain=5.53 (1.0), and Acceptance=3.60 (1.0) remained improved with large individual effects but fear and catastrophizing have re-emerged. Detailed individual data combining visual inspection and effect size calculation affords a focused view of the data that can immediately inform treatment delivery for this specific participant.

Figure 4.. Raw data from Treatment Non-responder.

The raw daily diary data across outcomes and timepoints for a Treatment Non-responder is depicted for visual inspection and descriptive analysis. Via visual inspection, no improvements are observed across outcomes. Via individual effect size calculations, when comparing baseline to 6-month follow-up (means phase A minus means phase D), Pain=2.22 (0.78) improved with medium individual effects. No other outcomes or significant effects were observed. Detailed individual data combining visual inspection and effect size calculation affords a focused view of the data that can immediately inform treatment delivery for this specific participant.

Figure 5.. Estimated regression lines based on the multilevel model for fear.

Individual participant trajectories are shown in color (N = 27), the overall average trajectory across participants is shown in black.

Figure 6.. Estimated regression lines based on the multilevel model for avoidance.

Individual participant trajectories are shown in color (N = 27), the overall average trajectory across participants is shown in black.