Group cognitive behavioral therapy (CBT) was found to benefit patients with chronic pain with low levels of literacy, education, and cognitive memory more than pain psychoeducation, according to a study published in the Journal of Pain.
Heterogeneity of treatment effects refers to variability in responses to evidence-based treatments due to differences between patients. As psychosocial therapies are increasingly used for the treatment of chronic pain, it is essential to understand the impact of sociodemographic and cognitive variables on their therapeutic effect.
The Learning About My Pain trial was a parallel-design, randomized, controlled, comparative effectiveness study (Clinicaltrials.gov identifier: NCT01967342) designed to evaluate the effect of psychosocial therapies on chronic pain by comparing literacy-adapted group CBT vs psychoeducation vs usual medical care. In this analysis of the trial, the pre- and post-treatment data of a total of 241 participants (mean age, 50.7 years; 71.8% women; 73.0% minority status; 75.6% in poverty; mean education, 11.9 years; mean reading level, grade 7.4) were examined. Study participants received CBT (n=83), psychoeducation (n=80), or usual care (n=78). Patients in the CBT and education groups also received standard medical care.
The CBT and pain psychoeducation regimens consisted of 10 weeks of training. The primary outcome was pain intensity assessed with the Brief Pain Inventory intensity subscale (BPI-Intensity). Secondary outcomes included pain interference evaluated with the BPI-Interference subscale, and depression assessed with the Patient Health Questionnaire-9.
The difference in pain intensity at 10 weeks in patients who had received CBT vs psychoeducation was found to be moderated by education level (P =.043) and primary literacy level (P =.012). The difference in pain interference between CBT and psychoeducation groups was found to be moderated by primary literacy (P =.042), health literacy (P =.023), and working memory (P =.038), and the difference in pain interference between the education and usual care groups was found to be moderated by poverty status (P =.022). Neither minority status nor sex were moderators of any group differences on any of the outcomes, and depression did not have any significant moderators.
Although patients with higher levels of literacy, education, and working memory appeared to benefit from both psychosocial interventions, participants with lower levels of these variables were found to benefit more from the CBT vs psychoeducation intervention. Researchers concluded that the simplification of the literacy-adapted CBT regimen, which was more structured than the psychoeducation regimen, contributed to minimizing outcome disparities.
Study strengths include a large sample size, precautions to minimize bias, and a high response rate. Study limitations include self-selection bias, and the examination of individual vs combined moderators.
“The pattern of findings indicates that the question for providers is less about whether to offer these psychosocial treatments, but which treatment will benefit a given patient most,” noted the authors.
Dyke BPV, Newman AK, Moraís CA, Burns JW, Eyer JC, Thorn BE. Heterogeneity of treatment effects in a randomized trial of literacy-adapted group cognitive-behavioral therapy, pain psychoeducation, and usual medical care for multiply disadvantaged patients with chronic pain. J Pain. April 2019. doi:10.1016/j.jpain.2019.04.006