Patient- and Site-Level Factors Associated with Abstinence Outcome in a Multisite Clinical Trial of a Technology-Delivered Psychosocial Intervention for Substance Use Disorders

• Activity Number: 362 - Contributed Poster Presentations: Mental Health Statistics Section
• Type: Contributed
• Date/Time: Tuesday, July 31, 2018 : 10:30 AM to 12:20 PM
• Sponsor: Mental Health Statistics Section
• Author(s): Martina Pavlicova* and Leila M. Vaezazizi and Aimee N. C. Campbell and Mei-Chen Hu and Edward V. Nunes
• Companies: Columbia University and New York State Psychiatric Institue and New York State Psychiatric Institute and Columbia University and New York State Psychiatric Institute
• Keywords: Multisite Clinical Trials; Site differences; Random effects; HGLM; Hierarchical generalized linear model; Substance use disorder

Abstract

AIM: Significant site effects have been identified in the majority of studies by National Drug Abuse Treatment Clinical Trials Network. Identifying patient- and site-level factors associated with site effects can provide useful additional information.

METHODS: In a 10-site clinical trial evaluating the effectiveness of a web-based psychosocial intervention of patients (n=507) with substance use disorders, the fixed main effect of site was significantly associated with the outcome of abstinence. We model site as a random effect and use a hierarchical generalized linear model (HGLM) to identify patient- and site-level factors associated with abstinence.

RESULTS: End-of-study abstinence varied from 6.1% to 40% by site. Only 6.7% of variability in abstinence outcome was accounted for by site. Older age (OR=1.40; 95% CI=1.15, 1.71), baseline abstinence (OR=2.77; 95% CI=1.73,4.45), and higher annual clinic admissions (OR=1.28; 95% CI=1.03,1.59) were significantly associated with increased likelihood of abstinence.

CONCLUSION: Only a small amount of variability in abstinence outcomes among sites can be explained by a combination of patient- and site-level factors.