Predictors of remission from body dysmorphic disorder after internet-delivered cognitive behavior therapy: a machine learning approach

Oskar Flygare,Erik Andersson,Jesper Enander,Christian Rück,David Mataix-Cols,Brjánn Ljótsson,Volen Z Ivanov

doi:10.1186/s12888-020-02655-4

Abstract

BackgroundPrevious attempts to identify predictors of treatment outcomes in body dysmorphic disorder (BDD) have yielded inconsistent findings. One way to increase precision and clinical utility could be to use machine learning methods, which can incorporate multiple non-linear associations in prediction models.MethodsThis study used a random forests machine learning approach to test if it is possible to reliably predict remission from BDD in a sample of 88 individuals that had received internet-delivered cognitive behavioral therapy for BDD. The random forest models were compared to traditional logistic regression analyses.ResultsRandom forests correctly identified 78% of participants as remitters or non-remitters at post-treatment. The accuracy of prediction was lower in subsequent follow-ups (68, 66 and 61% correctly classified at 3-, 12- and 24-month follow-ups, respectively). Depressive symptoms, treatment credibility, working alliance, and initial severity of BDD were among the most important predictors at the beginning of treatment. By contrast, the logistic regression models did not identify consistent and strong predictors of remission from BDD.ConclusionsThe results provide initial support for the clinical utility of machine learning approaches in the prediction of outcomes of patients with BDD.Trial registrationClinicalTrials.gov ID: NCT02010619.

Highlights

Previous attempts to identify predictors of treatment outcomes in body dysmorphic disorder (BDD) have yielded inconsistent findings
A recent meta-analysis of cognitive behavioural therapy (CBT) studies indicated that only 40—54% of patients enrolling in these trials were classified as treatment responders [11], which is lower than CBT for obsessive-compulsive disorder where response rates are 62–68% [12]
This study reports on a secondary analysis of data from a recent clinical trial investigating the efficacy of Internet-based CBT (ICBT) for adults with BDD [23, 24]

Summary

Introduction

Previous attempts to identify predictors of treatment outcomes in body dysmorphic disorder (BDD) have yielded inconsistent findings. Insight about the perceived defects varies on a continuum from fair to delusional, but is typically poor [5, 6] Another hallmark of BDD is the presence of repetitive behaviours (such as compulsive mirror gazing, excessive grooming or camouflaging of disliked body areas) in an attempt to hide or control the perceived defects [3]. Evidence-based treatments for BDD include selective serotonin re-uptake inhibitors (SSRIs) and cognitive behavioural therapy (CBT). Both treatment modalities are recommended in clinical guidelines [10] (published in 2005 and about to be updated) but the current evidence does not allow clinicians to decide which patients should be offered which treatment or whether they should be offered both. A recent meta-analysis of CBT studies indicated that only 40—54% of patients enrolling in these trials were classified as treatment responders [11], which is lower than CBT for obsessive-compulsive disorder where response rates are 62–68% [12]

Methods

Results

Discussion

Conclusion