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DEPERROR: Risks of systematic errors in drug and non-drug randomized clinical trials assessing intervention effects

Jesper Krogh1, Carsten Rygaard Hjorthøj1, Janus Christian Jakobsen2

  • 1Mental Health Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark.

Journal of Affective Disorders
|April 13, 2015
PubMed
Abstract

Insights

Randomized clinical trials for depression often have systematic errors. Drug trials showed better blinding, while non-drug trials had superior methodology, though both had high risks of bias.

Area of Science:

  • Clinical Trials Methodology
  • Psychiatry Research
  • Evidence-Based Medicine

Background:

  • Systematic errors in randomized clinical trials (RCTs) can overestimate treatment effects.
  • Assessing risks of bias is crucial for evaluating interventions for unipolar depression.

Purpose of the Study:

  • To systematically assess the risks of bias in RCTs for unipolar depression interventions.
  • To compare bias risks between drug and non-drug trials.
  • To examine trends in bias over time.

Main Methods:

  • Searched bibliographic databases for drug and non-drug RCTs in depression.
  • Assessed bias across domains: sequence generation, allocation concealment, blinding, intention-to-treat, selective reporting, funding.
  • Compared bias risks by intervention type and publication year (pre-1990, 1990-1999, 2000-2010).

Main Results:

  • Drug trials (N=775) showed better blinding (participants, providers, assessors) than non-drug trials (N=73).
  • Non-drug trials demonstrated superiority in sequence generation, allocation concealment, intention-to-treat, and baseline balance.
  • For-profit funding was higher in drug trials (41.5%) vs. non-drug trials (12.3%).
  • Risk of bias decreased over time in drug trials, but not significantly in non-drug trials.

Conclusions:

  • RCTs for depression included in this study (published before 2010) had high risks of bias.
  • These biases may distort treatment effect estimates.
  • Bias risks have decreased over time for drug trials, indicating methodological improvements.
Keywords:
BiasBlindingDepressionEffect estimatesRandomized clinical trialsTrial characteristics

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