Objectives: Evidence for the effectiveness of intensive interdisciplinary pain treatment (IIPT) for pediatric chronic pain is growing; however, little research has considered factors that contribute to differences in patients' treatment response. The present study utilized multilevel modeling to examine trajectory of change over time in functional disability from clinic assessment to 6-month follow-up in pediatric patients participating in IIPT, considering spatial distribution of pain, coping efficacy, and pain intensity.
Materials and methods: Participants included 110 pediatric patients (Mage=14.65, SD=2.37; localized pain, 27.3%; widespread pain, 72.7%) consecutively admitted into IIPT. Patients completed self-report measures of functional disability, pain intensity, and coping efficacy at pretreatment assessment, admission, weekly during IIPT, discharge, and several follow-ups.
Results: Analysis identified a model with 3 three-way interactions, including time, time squared, pain intensity, coping efficacy, and pain distribution, on functional disability. The spatial distribution of pain had the greatest impact on treatment trajectory in patients with widespread pain, high pain intensity, and poor coping efficacy; these patients demonstrated greater functional disability compared with patients with localized pain. In addition, patients with widespread pain and poor coping efficacy had the most functional disability across all levels of pain intensity. Patients with localized pain and poor coping efficacy demonstrated initial treatment gains, but evidenced an increase in functional disability at follow-up.
Discussion: Overall, spatial distribution of pain, coping efficacy, and pain intensity played an important role in patients' response to treatment. Better understanding of these variables could improve treatment response, particularly for the most severely disabled chronic pain patients.