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Cited by 38Digital Mental Health InterventionsSurvey Methodology and NonresponseMental Health Treatment and Access

Sampling bias in an internet treatment trial for depression

Open access
Donkin, L, Hickie, I B, Christensen, H, Naismith, S L, Neal, B, Cockayne, N L, Glozier, N·2012·Translational Psychiatry
DOI 10.1038/tp.2012.100PMC PMC3565809
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Abstract

Internet psychological interventions are efficacious and may reduce traditional access barriers. No studies have evaluated whether any sampling bias exists in these trials that may limit the translation of the results of these trials into real-world application. We identified 7999 potentially eligible trial participants from a community-based health cohort study and invited them to participate in a randomized controlled trial of an online cognitive behavioural therapy programme for people with depression. We compared those who consented to being assessed for trial inclusion with nonconsenters on demographic, clinical and behavioural indicators captured in the health study. Any potentially biasing factors were then assessed for their association with depression outcome among trial participants to evaluate the existence of sampling bias. Of the 35 health survey variables explored, only 4 were independently associated with higher likelihood of consenting-female sex (odds ratio (OR) 1.11, 95% confidence interval (CI) 1.05-1.19), speaking English at home (OR 1.48, 95% CI 1.15-1.90) higher education (OR 1.67, 95% CI 1.46-1.92) and a prior diagnosis of depression (OR 1.37, 95% CI 1.22-1.55). The multivariate model accounted for limited variance (C-statistic 0.6) in explaining participation. These four factors were not significantly associated with either the primary trial outcome measure or any differential impact by intervention arm. This demonstrates that, among eligible trial participants, few factors were associated with the consent to participate. There was no indication that such self-selection biased the trial results or would limit the generalizability and translation into a public or clinical setting.

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  • This sample skew is typical in studies with chronically ill populations, as females have a higher proportion of chronic health conditions and are more likely to participate in eHealth interventions, creating a self-selection bias.

    “This sample skew is typical in studies with chronically ill populations, as females have a higher proportion of CHCs and are more likely to participate in eHealth interventions, creating a self-selection bias (Donkin et al., 2012).”

    From ACT2COPE: A pilot randomised trial of a brief online acceptance and commitment therapy intervention for people living with chronic health conditions during the COVID-19 pandemic (2023) · cites this paper as Donkin et al., 2012

    The Discussion reports that female sex was associated with greater likelihood of consenting to an internet-delivered depression trial among adults aged 45 or older at high cardiovascular risk, supporting a sex-related self-selection difference. It does not establish that females have a higher proportion of chronic health conditions or that this pattern is typical across chronically ill populations. The Discussion’s Future direction section also says the observed sampling differences were not shown to bias trial results. (LLM, conf=0.88)

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Research works printed but not linked: 1

  1. Rothman KJ Greenland S Precision and validity in epidemiologic studiesIn: Rothman KJ, Greenland S, (eds). Modern Epidemiology Lippincott Williams & Wilkins: Philadelphia, PA 1998 115 134

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Authors
Donkin, L., Hickie, I. B., Christensen, H., Naismith, S. L., Neal, B., Cockayne, N. L., & Glozier, N.
Affiliations
  • The University of Sydney (AU)
  • Black Dog Institute (AU)
  • The George Institute for Global Health (AU)
Corresponding author
Glozier, N
ORCID
Venue
Translational Psychiatry
Publisher
Springer Science and Business Media LLC
Published
2012-10-23
Volume
2
Issue
10
Pages
e174-e174
ISSN
2158-3188 (ISSN-L)
DOI
10.1038/tp.2012.100
PMC
PMC3565809
OpenAlex
W1981670546
Cited by
38
References
64
Citations by year
2026: 5 · 2024: 1 · 2023: 2 · 2022: 4 · 2021: 4 · 2020: 1 · 2019: 1 · 2018: 4 · 2016: 5 · 2015: 1 · 2014: 6 · 2013: 4
FWCI
4.97
Type
journal article
Language
en
Open access
Licence
Locations
  • Translational Psychiatry (publishedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • The Sydney eScholarship Repository (The University of Sydney) (submittedVersion, cc-by-nc-nd)
Funders
  • National Heart Foundation of Australia (G08S 4048)
  • Cancer Council NSW
Topics
  • Social Sciences › Psychology › Applied Psychology › Digital Mental Health Interventions
  • Social Sciences › Sociology and Political Science › Survey Methodology and Nonresponse
  • Social Sciences › Psychology › Social Psychology › Mental Health Treatment and Access
Keywords
sampling bias, online psychological intervention, internet-based cognitive behavioral therapy, depression, clinical trial participation, self-selection, generalizability of trial results, community-based cohort
MeSH terms
Aged, Depression, Depressive Disorder, Educational Status, Female, Humans, Male, Middle Aged, Sex Factors, Therapy, Computer-Assisted, Cohort Studies, Cognitive Behavioral Therapy, Selection Bias, Multivariate Analysis, Randomized Controlled Trials as Topic, Internet

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