Cost-utility and Physiological Effects of ACT and BATD in Patients With Chronic Pain and Depression

Overview

Objectives: (1) To analyze the effectiveness of adding a group-based form of Acceptance and Commitment Therapy (ACT) or a behavioural activation program for depression (TACD) to the treatment as usual (TAU) for patients diagnosed of chronic pain and comorbid mild-moderate major depression; (2) To examine the cost-utility of these psychological treatments from healthcare and societal perspectives; (3) To measure a set of biomarkers alongside the RCT in order to know the physiological underpinnings of these psychological therapies and to identify potential predictors of treatment response. Methodology: 12-month multisite, randomised, controlled trial (RCT) Centres: Parc Sanitari Sant Joan de Déu (St. Boi de Llobregat) and Hospital del Mar (Barcelona). Participants. 225 adult patients with chronic pain that meet the diagnostic criteria for mild-moderate major depression will be randomly assigned to one of the three study arms: TAU + ACT vs. TAU + TACD vs. TAU. Primary outcome: Quality of life. Secondary outcomes: pain intensity, depression severity, anxiety symptoms, pain catastrophising, and pain acceptance. Costs to the healthcare system and to society and quality adjusted life years (QALYs). In addition, the empirically validated app Multicenter Pain Monitor® will be used to monitor participants alongside the treatments (ecological momentary assessment). Biomarkers: hair cortisol and cortisone, corticosteroid-binding globulin (CBG), ACTH and cortisol in plasma, and genotyping of 5 polymorphisms in the FKBP5 gene involved in the regulation of the hypothalamic-pituitary-adrenal axis activity, cytokines, Th1: IL-6, IL-8, TNF-α; cytokines Th2: IL-10 + hsCRP test, and vitamin D levels. Main statistical analyses: Intention-to-Treat analyses that will include all participants who undergo random allocation, using multiple imputation to replace missing values. Linear mixed-effects models will be performed using Restricted Maximum Likelihood to estimate the parameters. Calculation of between-groups effect sizes using Cohen's d and of the number-needed-to-treat. Economic evaluation: cost-utility ratios evaluated by applying bootstrapping techniques, acceptability curves, and sensitivity analyses.

The IMPACT Project's main objective is to determine the effectiveness of adding to the standard care of patients with chronic pain and mild to moderate major depression a group programme based on ACT or a group programme based on BATD and analyse the cost-utility of these psychological treatments from a health and social perspective. Likewise, both in chronic pain and in other usually associated psychiatric diseases, there is a ubiquitous lack of knowledge about what specific psychological and physiological mechanisms are modified by these third generation psychotherapies and how they relate to the observed clinical results. The potential predictors of response to these treatments are also unknown. In chronic musculoskeletal pain where central sensitization plays an important role, alterations have been found in different markers associated with an increased experience of pain. Some of these alterations in markers (e.g. high levels of pro-inflammatory cytokines) would also appear to be shared with other psychiatric diseases (major depression), a fact that would suggest a possible common mechanism involved in the etiopathogenesis of these diseases. Third generation psychotherapies have proven effective for pain management and regulation of the immune response. The IMPACT Multicentre Project (Improving Pain and Depression with ACT and BATD) will significantly expand the limited knowledge available about how ACT and BATD therapies exert their effects on relevant clinical improvement variables and will try to identify response predictive factors to these treatments.