Smoking cessation treatment attendance among smokers with substance use disorders.

Send correspondence to: Gema Aonso Diego. Unidad Clínica de Conductas Adictivas, Fac. Psicología, Univ. Oviedo, Plaza Feijoo s/n, 33003 Oviedo, España. Tel. 985104189. Email: aonsogema@uniovi.es Attrition rates pose a considerable problem in smoking cessation intervention, especially with hard-to-treat population (Lappan, Brown & Hendricks, 2019; Lien, Bolstad & Bramness, 2021). In this sense, non-attendance to a smoking cessation treatment decreases effectiveness of these interventions (Garey et al., 2020; Martínez-Vispo, López-Durán, Rodríguez-Cano, Senra & Becoña, 2021), and also brings about several resource-related costs (e.g., therapists time, urinalysis, materials) (Brorson, Arnevik, Rand-hendriksen & Duckert, 2013; Cooper, Kline, Baier & Feeny, 2018). All of the above results in a decrease in the cost-effectiveness of smoking cessation treatments in this population (Cooper et al., 2018). Although multiple researches on dropping out of smoking cessation treatments has been examined in SUD population, to our knowledge, no previous studies have examined specific predictors associated with treatment attendance in this population. Analyzing which factors predict non-attendance is expected to be clinically informative because it will enable to improve the efficacy and cost-effectiveness of existing smoking treatments. Amid this background, this exploratory study sought to examine which baseline variables (i.e., sociodemographic, tobacco, and substance use related variables) were associated with non-attendance to the smoking cessation treatment. This is a secondary study derived from a parent randomized controlled trial (Aonso-Diego, González-Roz, Krotter, García-Pérez & Secades-Villa, 2021). The eligibility criteria were: being ≥ 18 years old, smoking at least 10 cigarettes per day within the last year, and being enrolled in an outpatient substance use treatment. Participants were excluded if they had severe mental disorders (i.e., active psychotic disorder, or suicidal ideation), current cannabis use, or were receiving any other smoking cessation treatment, either psychological or pharmacological. Out of 101 participants who were assessed in an individual baseline interview, 15 were excluded for not meeting inclusion criteria, and a total of 86 patients were assigned to smoking cessation treatment. A binary logistic regression analysis was performed with attrition groups as dependent variable. The independent variables introduced were: sociodemographic (i.e., sex, age, employment status, marital status, and educational level), smoking features (i.e., cigarettes per day, years of regular use, nicotine dependence, urine cotinine levels, previous quit attempts, and current motivation to quit), and substance use related characteristics, that is, primary substance use (cocaine, alcohol, opioids, or cannabis), days of substance abstinence, and days on substance use treatment. Treatment condition [(cognitive-behavioral treatment (CBT) or CBT + contingency management (CM)] was also included in the analyses. Findings indicate that out of 86 participants allocated to treatment groups, 65 (75.58%) patients began the treatment, and the remaining 21 (24.42%) patients did