Cost-effectiveness and cost-utility evaluation of the individual vs. group transdiagnostic psychological treatment for emotional disorders in Primary Care (PsicAP-Costs)

The recruitment will be accomplished in three different primary care settings of the province of Cordoba: the "Carlos Castilla del Pino" Health Centre, the "Levante Sur Dr. Manuel Barragán Solís" Health Centre, and the Community Mental Health Unit of Montilla. General practitioners (GPs) will invite the patients in whom they suspect a diagnosis of emotional disorder (ED) to participate in the study. Participants will be informed and asked for the written consent, and an assessor-investigator (the blinded party) will administer the instruments (see Materials).

Participants will be only adult (18-65 year-old) men and women who have mild or moderate EDs (i.e. depressive, anxiety and/or somatoform disorders) according to the PHQ subscales: the PHQ-4 for the screening, and the PHQ-9, the GAD-7, the PHQ-PD, and the PHQ-15 to determine the kind of disorder and the severity level. Those who do not have an ED and/or do have a severe mental illness, will be returned to their GPs. Participants with a recent, severe suicide attempt, or with a high level of impairment (according to the SDI) will be excluded as well.

The sample size needed would be 128.

Start date of the recruitment: September 2021.

Participants will be allocated, by a non-assessor investigator with a computer-generated randomization, to the three experimental groups (1:1:1 ratio):

• Group brief transdiagnostic cognitive-behavioural therapy (group tCBT)

An adaptation of the Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UP) (Barlow et al., 2015) and the IAPT programme (Clark, 2018). It has been developed by Cano-Vindel (González-Blanch et al., 2018) and consists in seven 90-minute sessions, provided by a non-assessor clinical psychologist in 12-16 weeks, with 8-10 participants per group. Sessions are weekly or biweekly, reducing their frequency as the intervention advances. The activities and homework proposed are supported with materials such as theory documents, a CD for progressive muscle relaxation, self-recording sheets, and a therapy web (www.desordenesemocionales.es).

• Individual brief transdiagnostic cognitive-behavioural therapy (individual tCBT)

An adaption of the group therapy, with the same phases. However, since it is an individual intervention, it is more flexible than group one and its contents and duration can be personalized. This intervention consists of a minimum of 6 and a maximum of 8 sessions of 30-60 minutes, provided by a clinical psychologist not involved in the assessments.

• Treatment as usual (TAU)

Participants in this group will be provided the common primary care treatment by the GP, in a face-to-face consultation that seldom exceeds 10 minutes. TAU usually consists in pharmacological treatment prescribed by the GP, however, it might also consist in practical advice or even non-treatment (Watts et al., 2015). The first consultation will count as part of the recruitment process and, if the patient accepts to participate in the trial, no therapeutic help will be provided to them until they are allocated. Once in the TAU intervention, if the practitioner recommended any psychological treatment as part of it (e.g., referral to specialized care), the participant would be excluded to avoid contamination between clusters. TAU has not a specific amount of sessions; it will finish when the GP considers the patient is recovered.

References Barlow DH, Farchione TJ, Fairholme CP, Ellard KK, Boisseau CL, Allen LB, et al. Protocolo Unificado para el Tratamiento Transdiagnóstico de los Trastornos Emocionales [Unified Protocol for Transdiagnostic Treatment of Emotional Disorders: Therapist Guide and Patient Guide]. 1st ed. Alianza; 2015.

Clark DM. Realizing the Mass Public Benefit of Evidence-Based Psychological Therapies: The IAPT Program. Annu Rev Clin Psychol. 2018 May 7;14:159-183. doi: 10.1146/annurev-clinpsy-050817-084833. Epub 2018 Jan 19.   PubMed ID: 29350997

González-Blanch C, Umaran-Alfageme O, Cordero-Andrés P, Muñoz-Navarro R, Ruiz-Rodríguez P, Medrano LA, et al. Tratamiento psicológico de los trastornos emocionales en Atención Primaria: el manual de tratamiento transdiagnóstico del estudio PsicAP. Ansiedad y Estrés. 2018;24(1).

Watts SE, Turnell A, Kladnitski N, Newby JM, Andrews G. Treatment-as-usual (TAU) is anything but usual: a meta-analysis of CBT versus TAU for anxiety and depression. J Affect Disord. 2015 Apr 1;175:152-67. doi: 10.1016/j.jad.2014.12.025. Epub 2014 Dec 15.   PubMed ID: 25618002

Instruments will be administered again after each intervention is finished. They will be administered again 6 and 12 months later in order to assess if the potential changes remain over time.

ANALYSIS OF CLINICAL EFFECTIVENESS

Data analyses will be accomplished through the SPSS Statistics software. Effectiveness-related data will be analysed with both intention-to-treat and per protocol approaches. After homogeneity intra- and inter-groups is checked, changes over time (baseline, post-intervention, and follow-ups) in primary and secondary outcomes will be analysed through linear mixed models (LMM). Likewise, effect sizes (Cohen's d ) will be calculated, as well as their accuracy considering the number of treatment sessions received. Moreover, it will be estimated the percentage of patients in each cluster who experience a 50% decrease in the number of clinical symptoms and scores by one standard deviation, as well as the percentage of cases with a probable ED before and after receiving treatment (according to cut-off criteria). Therapeutic success criteria will be the obtaining of post-intervention means significantly lower ( p ≤ .05) and medium/large effect sizes significantly greater than the control's, especially in the ED scores. Clusters will be also compared regarding impairment, quality of life, emotion regulation biases, and satisfaction with the treatment.

COST ANALYSIS

Cost-related data will be collected through the medical records and ad hoc questionnaires, from 3 months prior to inclusion in the study to 12 months after the intervention has finished. Direct costs will be calculated by adding the ED-related costs due to medication use (antidepressants, anxiolytics, hypnotics, and sedatives), medical tests and other health services, and health personnel. Medication costs will be calculated by multiplying the price per milligram (€/mg) according to the Vademecum International (www.vademecum.es) by the daily dose (mg) and the number of days of drug treatment. Cost data related to medical tests and use of health services will be obtained through the fee information published in the Andalusian Health Service’s official web. Since a group psychotherapy session has not a specific tariff, it will be considered as a GP consultation without medical tests as GPs and clinical psychologists have similar base salaries. Indirect costs will be calculated by multiplying the days of ED-related sick leave from work by the daily minimum salary at the moment, and it will be also taken into account if it is necessary a replacement worker. Total costs will be obtained summing both direct and indirect costs.

ANALYSES OF COST-EFFECTIVENESS AND COST-UTILITY

On the one hand, cost-effectiveness analysis will be accomplished by calculating the incremental cost-effectiveness ratios (ICERs). However, cost-effectiveness analyses may be questioned, since they rate the more appropriate intervention based only on the clinical perspective. On the other hand, cost-utility analyses use the intervention health-related utilities, subjectively rated by participants. Therefore, they depend on a social perspective, being the participants who express their preferences based on the value they assign to their health status. The EQ-5D-5L will be used to calculate those utilities as QALYs, and the latter to obtain the incremental cost-utility ratios (ICURs). Since follow-ups will not last more than 12 months post-intervention, neither costs nor results will be subject to discount. The bootstrapping method (a resampling method) will be used to obtain more accurate ICERs and ICURs. Missing data will be analysed through Student's t and χ2 ² tests regarding ED severity level, sex, and age; this will allow us to know if missing data due to dropout are related to chance or not. Finally, a sensitivity analysis will be done to test the robustness of cost-effectiveness and cost-utility results.