Cost-Utility of Attachment-Based Compassion Therapy (ABCT) and Mindfulness-Based Stress Reduction (MBSR) in the Management of Depressive, Anxious, and Adjustment Disorders in Mental Health Settings: Economic Evaluation Alongside a Randomized Controlled Trial

The initial screening for participants included 104 individuals, 90 of which met the selection criteria (a detailed description of these criteria is presented later within this section). In terms of sociodemographic and clinical characteristics of the participants, we could not observe any statistically significant difference across the three treatment arms at baseline (Table 1). This set of participants was randomly allocated to the three treatment groups: 30 receiving ABCT, 30 receiving MBSR, and 30 receiving TAU as standalone treatment. The attrition rate was reasonable since 23 participants (77%) from the ABCT arm, 21 participants (70%) from the MBSR arm, and 25 (83.3%) from the TAU arm completed the 6-month follow-up assessment, respectively. We did not observe any selective dropout.

In order to be admitted in the study, prospective participants had to meet the following criteria: (1) having an age range within the threshold 18–75 years old; (2) presenting a depressive and/or anxious disorder, or an adjustment disorder with depressive and/or anxious symptomatology (based on the DSM-5 criteria); (3) the depressive/anxious disorder should have a mild-to-moderate severity according to the clinical criteria; (4) being fluent in Spanish; and (5) having signed an informed consent form. Exclusion criteria included (1) having done any type of meditative or contemplative practice within the previous 12 months; (2) presence of any diseases that could affect the central nervous system; (3) presence of any other psychiatric diagnoses or acute psychiatric illnesses; (4) diagnosis of any medical condition or infectious or degenerative disease that could affect mood; and (5) presence of delusional ideas or hallucinations. Diagnoses were conducted by psychiatrists or psychologists using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition Research Version 5 (First et al., 2015). In terms of compliance with the assigned treatments, 73% of ABCT participants and 60% of MBSR participants attended six or more sessions. Figure 1 shows the flow of participants through the economic evaluation.

The study protocol was approved by the Ethics Committee of the General University Hospital of Castellón (7/2017). All procedures performed in this study were in accordance with the criteria of the 1964 Declaration of Helsinki and the Declaration of Madrid of the World Psychiatric Association. Confidentiality of participants’ personal information was protected under the Spanish Organic Law on Protection of Personal Data and Guarantee of Digital Rights (3/2018, LOPD-GDD) and under all relevant EU legislation on privacy and data protection.

A detailed description of the randomized controlled trial (RCT) protocol is provided elsewhere (Montero-Marin et al., 2019b). In brief, the RCT study includes three treatment groups, assessed at baseline, at post-intervention, and at 6-month follow-up assessment. Potential participants have been recruited by mental health professionals between September 2018 and February 2019. Once the required sample size was achieved, the participants were interviewed at the mental health unit by a clinical psychologist, who confirmed suitability according to the aforementioned selection criteria. Participants received a general overview of the study and were informed of the option to withdraw from the study at any time without it affecting the quality of the usual care. An independent statistician computed a simple randomization sequence after baseline evaluation. Written informed consent was obtained from all participants included in the study before randomization. Then, participants were allocated to treatment-as-usual (TAU) + ABCT, TAU + MBSR, or TAU alone using a parallel assignment and a computer-generated randomization list.

As mentioned, both ABCT and MBSR were administered in addition to treatment as usual (TAU) as provided by healthcare professionals of the public Spanish National Health System. TAU included the usual health and social care that would be delivered by the Spanish NHS, which for patients with anxious-depressive disorders usually consists of pharmacological treatment (mainly psychotropic medications) plus some psychological counseling (delivered by a psychiatrist or a clinical psychologist) using classical CBT as general framework.

The economic evaluation alongside this pilot RCT was conducted according to the CHEERS statement (Husereau et al., 2013) and the Good Research Practices for Cost-Effectiveness Analysis Alongside Clinical Trials (Ramsey et al., 2015). Efficacy results of this RCT (registered in Clinicaltrials.gov; NCT03425487) have been reported elsewhere (Collado-Navarro et al., 2021).

Participants underwent the MBSR protocol developed at the University of Massachusetts Medical School, USA, consisting of 8 weekly 2-hr-long group sessions of mindfulness training. MBSR was developed to help people with chronic pain and stress-related conditions (Kabat-Zinn, 1982). To avoid exhaustion or withdrawal from the study and to make it structurally equivalent to ABCT, session duration and daily homework assignments were slightly shortened: sessions took 2 hr instead of 2.5 hr and daily homework assignments took approximately 15–20 min. The half-day of silent MBSR retreat between sessions 6 and 7 was discarded in this study. Both the group and the homework sessions included elements of MBSR practice such as body scan, sitting meditation, and mindful movements/stretches, with the purpose of helping patients to relate to their physical and psychological symptoms conditions in more accepting and non-judgmental ways. The MBSR instructor was a psychologist with accredited experience who delivered the intervention using a group format (up to 10–15 participants per group).

ABCT is a compassion-based program focused on augmenting the patients’ ability to be considerate and kind towards (i) themselves and their own suffering experience, and (ii) others’ experience of suffering (García-Campayo et al., 2016). ABCT comprises 8 weekly 2-hr sessions. It includes formal practices of mindfulness and visualizations based on self-compassion and the attachment style that was generated in childhood. Specific practices oriented to augment the patients’ ability to be considerate and kind towards themselves and their own experience of suffering as well as others’ experience of suffering are included. The program includes daily homework assignments that take approximately 15–20 min to complete. The instructor was a psychologist with accredited experience in ABCT who delivered the intervention using a group format (up to 10–15 participants per group).

Healthcare costs have been computed by summing up the costs derived from medication, medical tests, use of health-related services, and cost of the staff delivering ABCT and MBSR. Medication costs have been computed using prices per milligram as available in the Vademecum International (Red Book; edition 2020), which included value-added taxes. Those unit prices per milligram have been multiplied by the daily dosage used (in milligrams) and the number of days that the treatment was received. The main source of the unit cost data for medical tests and health services use was the SOIKOS database (http://​esalud.​oblikue.​com/​). The calculation of the total costs of the ABCT and MBSR treatments was based on the price per participant per group session of a clinical psychologist, as indicated by the Spanish Official College of Psychology. The cost of both treatments was assumed to be consistent across all sessions and groups, but the number of patients attending those sessions was not. Therefore, treatment costs were dependent on the number of sessions attended by each patient. Unit costs are expressed in Euros (€) based on 2020 prices. Table 2 shows the unit costs of healthcare resources. It was not necessary to apply a discount factor to the costs because the time horizon was less than a year.

Utility scores were obtained from the EQ-5D-3L following the methods described by previous studies (Devlin et al., 2020; Rabin & de Charro, 2001) and were computed to rate patients’ HRQoL from 0 (as bad as death) to 1 (perfect health). These scores reflect how the general population values the health status described by the individual, which is preferred for economic evaluations from a broad perspective. Quality-adjusted life years (QALYs) were calculated using the methods described in Richardson and Manca (2004): the baseline and follow-up utility scores, obtained after applying the Spanish tariffs to the participants’ answers to the EQ-5D-3L, were added and divided by 2, and then multiplied by 0.5, as the timeframe of the study was half a year. QALYs are a measure which takes into account both disease-burden and mortality and can be used to provide a common metric to assess the extent of the benefits gained from different treatments in terms of HRQoL and survival for the patient. A QALY places a weight on time in different health states. A year of perfect health is worth 1 and a year of less than perfect health is worth less than 1.

We computed incremental cost-utility ratios (ICURs), defined as the ratio between incremental costs and incremental effects (QALYs). In the cost-utility analysis, incremental costs and incremental effects were estimated computing Seemingly Unrelated Regressions (Willan et al., 2004). Using this methodology, cost and outcome measures were included in a bivariate system that implemented a regression of costs and QALYs on treatment allocations, i.e., whether they were assigned to TAU + ABCT, TAU + MBSR, or TAU. As usual, when a treatment was clinically superior and cost saving, it was referred to as a “dominant” (vs. dominated) intervention (Cohen & Reynolds, 2008). The regressions controlled for the following baseline variables: treatment group, gender, age, marital status, living arrangements, education level, work status, and number of treatment sessions attended. Estimates were run using 1000 bootstrap replications to address a possible skewness in the distribution of the dependent variables (Briggs et al., 1997). We conducted a complete case analysis (21 patients without 6-month follow-up data were excluded). Statistical analyses were carried out using SPSS v26.0 and STATA v16.0.

The findings of the present study should be considered preliminary and interpreted in the light of the following limitations. First, the small sample size limits the precision of the findings, so they need replication in large samples. Second, our analyses are only based on data collected through self-report measures (EQ-5D-3L for assessing quality of life and CSRI for medical costs), a procedure that implies a recall bias. Third, there is a shortage of psychotherapists certified in MBSR and ABCT or sufficiently experienced to deliver such programs in the Spanish healthcare system to teach MBSR and ABCT which limits the implementation of both protocols in real world clinical practice. Lastly, our sample mainly comprised middle-aged women from Spain, which limits the generalizability of the findings to other European countries. Future research should test the efficiency of these programs with larger samples and include data from public registers (e.g., service use). In addition, longer follow-up periods would increase knowledge about how much time remain these effects on healthcare utilization.