Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis

Background: Dropout rates and factors contributing to dropout in drug and placebo groups in pharmacotherapy trials for posttraumatic stress disorder (PTSD) are not well understood.Objective: This study aimed to examine differences in all-cause study dropouts between drug and placebo groups, using co...

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Main Authors: Simonne L. Wright, Anna Kessler, Marit Sijbrandij, Eirini Karyotaki, Pim Cuijpers, Jonathan Bisson, Kathleen Brady, Sheila M. Dowd, Boadie W. Dunlop, Mark H. Pollack, Barbara O. Rothbaum, Soraya Seedat
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Language:English
Published: Taylor & Francis Group 2025-12-01
Series:European Journal of Psychotraumatology
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Online Access:https://www.tandfonline.com/doi/10.1080/20008066.2025.2504839
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author Simonne L. Wright
Anna Kessler
Marit Sijbrandij
Eirini Karyotaki
Pim Cuijpers
Jonathan Bisson
Kathleen Brady
Sheila M. Dowd
Boadie W. Dunlop
Mark H. Pollack
Barbara O. Rothbaum
Soraya Seedat
author_facet Simonne L. Wright
Anna Kessler
Marit Sijbrandij
Eirini Karyotaki
Pim Cuijpers
Jonathan Bisson
Kathleen Brady
Sheila M. Dowd
Boadie W. Dunlop
Mark H. Pollack
Barbara O. Rothbaum
Soraya Seedat
author_sort Simonne L. Wright
collection DOAJ
description Background: Dropout rates and factors contributing to dropout in drug and placebo groups in pharmacotherapy trials for posttraumatic stress disorder (PTSD) are not well understood.Objective: This study aimed to examine differences in all-cause study dropouts between drug and placebo groups, using conventional meta-analysis and an exploratory predictor analysis of individual participant data from three trials.Method: We included randomized controlled trials (RCTs) of adults with PTSD, comparing drug monotherapy with placebo. Forty-three RCTs (n = 4829) were included in a conventional meta-analysis. Additionally, we conducted a small exploratory predictor analysis including participant-level data from three RCTs (n = 246).Results: In the conventional meta-analysis, study dropout was marginally lower in the drug relative to the placebo group, but the difference was not significant, RR = 0.92, 95% CI [0.83, 1.02], p = .099. Drug class, dosing regimen, population, study duration, or gender were not related to dropout.In the exploratory predictor analysis, study dropout did not differ significantly between drug and placebo groups (p = .617). In the drug group, gender was a significant predictor for dropout, with males having higher dropout rates (p = .046). When controlling for baseline PTSD symptom severity, gender was no longer a statistically significant predictor (p = .051). None of the other predictors in drug, placebo, and combined group analyses were significant in predicting drop-out.Conclusions: This study demonstrated that study dropout rates in monotherapy pharmacotherapy RCTs for PTSD do not significantly differ between drug and placebo groups. These findings underscore the need for further research to identify the factors contributing to dropout in PTSD pharmacotherapy trials and to develop tailored treatment adherence strategies. Additionally, they highlight the importance of pooling participant-level data to facilitate more comprehensive and granular analyses in future research.
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spelling doaj-art-57a0a3fdcece42fcbd014764288b78f82025-08-20T03:16:31ZengTaylor & Francis GroupEuropean Journal of Psychotraumatology2000-80662025-12-0116110.1080/20008066.2025.2504839Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysisSimonne L. Wright0Anna Kessler1Marit Sijbrandij2Eirini Karyotaki3Pim Cuijpers4Jonathan Bisson5Kathleen Brady6Sheila M. Dowd7Boadie W. Dunlop8Mark H. Pollack9Barbara O. Rothbaum10Soraya Seedat11Department of Clinical, Neuro- and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsDepartment of Clinical, Neuro- and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsDepartment of Clinical, Neuro- and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsDepartment of Clinical, Neuro- and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsDepartment of Clinical, Neuro- and Developmental Psychology, World Health Organization Collaborating Center for Research and Dissemination of Psychological Interventions, Amsterdam Public Health Research Institute, Vrije Universiteit Amsterdam, Amsterdam, The NetherlandsDivision of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UKPsychiatry and Behavioral Sciences, College of Medicine, Medical University of South Carolina, Charleston, SC, USADepartment of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USADepartment of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USADepartment of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USADepartment of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USASouth Africa PTSD Research Programme of Excellence, Department of Psychiatry, Faculty of Medicine & Health Sciences, Stellenbosch University, Stellenbosch, South AfricaBackground: Dropout rates and factors contributing to dropout in drug and placebo groups in pharmacotherapy trials for posttraumatic stress disorder (PTSD) are not well understood.Objective: This study aimed to examine differences in all-cause study dropouts between drug and placebo groups, using conventional meta-analysis and an exploratory predictor analysis of individual participant data from three trials.Method: We included randomized controlled trials (RCTs) of adults with PTSD, comparing drug monotherapy with placebo. Forty-three RCTs (n = 4829) were included in a conventional meta-analysis. Additionally, we conducted a small exploratory predictor analysis including participant-level data from three RCTs (n = 246).Results: In the conventional meta-analysis, study dropout was marginally lower in the drug relative to the placebo group, but the difference was not significant, RR = 0.92, 95% CI [0.83, 1.02], p = .099. Drug class, dosing regimen, population, study duration, or gender were not related to dropout.In the exploratory predictor analysis, study dropout did not differ significantly between drug and placebo groups (p = .617). In the drug group, gender was a significant predictor for dropout, with males having higher dropout rates (p = .046). When controlling for baseline PTSD symptom severity, gender was no longer a statistically significant predictor (p = .051). None of the other predictors in drug, placebo, and combined group analyses were significant in predicting drop-out.Conclusions: This study demonstrated that study dropout rates in monotherapy pharmacotherapy RCTs for PTSD do not significantly differ between drug and placebo groups. These findings underscore the need for further research to identify the factors contributing to dropout in PTSD pharmacotherapy trials and to develop tailored treatment adherence strategies. Additionally, they highlight the importance of pooling participant-level data to facilitate more comprehensive and granular analyses in future research.https://www.tandfonline.com/doi/10.1080/20008066.2025.2504839Individual participant data meta-analysisPTSDpredictorspharmacotherapytreatmentMetaanálisis de datos individuales de participantes
spellingShingle Simonne L. Wright
Anna Kessler
Marit Sijbrandij
Eirini Karyotaki
Pim Cuijpers
Jonathan Bisson
Kathleen Brady
Sheila M. Dowd
Boadie W. Dunlop
Mark H. Pollack
Barbara O. Rothbaum
Soraya Seedat
Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
European Journal of Psychotraumatology
Individual participant data meta-analysis
PTSD
predictors
pharmacotherapy
treatment
Metaanálisis de datos individuales de participantes
title Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
title_full Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
title_fullStr Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
title_full_unstemmed Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
title_short Exploring study dropout in drug trials for adults with PTSD: insights from a conventional and individual participant data meta-analysis
title_sort exploring study dropout in drug trials for adults with ptsd insights from a conventional and individual participant data meta analysis
topic Individual participant data meta-analysis
PTSD
predictors
pharmacotherapy
treatment
Metaanálisis de datos individuales de participantes
url https://www.tandfonline.com/doi/10.1080/20008066.2025.2504839
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