Predictors of Dropout in a Cohort of People Undergoing Treatment for Borderline Personality Disorder in a Public Community Mental Health Service: A Time-to-Event Analysis

Background: Dialectical Behaviour Therapy (DBT) is an effective evidence based treatment for Borderline Personality Disorder (BPD). However, irrespective of the success of the treatment, a dropout rate of approximately 30%-40% is regarded as the norm. In this analysis we aimed to investigate whether early predictors of dropout can be identified from baseline data. Methods: Between 2014 and 2017, data was collected from 196 participants at multiple timepoints as part of a coordinated multisite study of standard DBT treatment for community based service users being treated for BPD in Ireland. Dropout was strictly defined as per the standard DBT programme four-miss rule. For this analysis data were censored at 48 weeks and risk factors for dropout were identified using a Cox proportional hazards model that adjusted for age and gender. Engagement with phone coaching in the first month was examined as a time dependant covariate.  Outcomes: Of the 196 participants, 12 (6%) were censored and 9 (4%) removed leaving 187 for analysis of whom, 109 (58%) completed and 66 (32%) dropped out. Results from univariable Cox proportional hazard regressions found off-label use of anti-psychotic medication was associated with an increased risk of drop-out, while full time employment status, receipt of disability support and engagement with phone coaching in the first month were associated with a reduced risk of dropout. Entering these variables in a multivariable Cox proportional hazard regression found off-label use of anti-psychotic medication (adjusted HR 2·69, 95% CI 1·50 - 4·83; p=0·001); full time employment status (adjusted HR 0.23, 95% CI 0.07-0.77; p=0.02) and disability (adjusted HR 0.20, 95% CI 0.05-0.85; p=0.03) remained significant predictors. Interpretation: Awareness of employment status and off-label prescription of anti-psychotic medication at baseline as significant risk factors for dropout may provide clinicians with valuable insight when starting treatment and could potentially inform treatment approach.  Funding Information: This work, as part of the The National DBT Project, was funded by the Irish Health Service Executive (HSE) and the National Office for Suicide Prevention (NOSP). The fund is administered via the National Suicide Research Foundation (NSRF). Declaration of Interests: We declare no competing interests. Ethics Approval Statement: All procedures were reviewed and approved by the following research ethics committees: Clinical Research Ethics Committee of the Cork University Teaching Hospitals, Galway Clinical Research Ethics Committee, HSE Mid Western Regional Hospital Research Ethics Committee, HSE North East Area Research Ethics Committee, HSE South East Area Research Ethics Committee, Linn Dara & Beechpark Ethics Committee; Naas General Hospital Ethics Committee; Saint John of God Hospitaller Ministries Research Ethics Committee and Sligo General Hospital Research Ethics Committee.