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Cited by 834Statistical Methods in Clinical TrialsMeta-analysis and systematic reviewsAdvanced Causal Inference Techniques

Randomized versus historical controls for clinical trials

Sacks, Henry., Chalmers, Thomas C.., Smith, Harry.·1982·The American Journal of Medicine
DOI 10.1016/0002-9343(82)90815-4
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Abstract

To compare the use of randomized controls (RCTs) and historical controls (HCTs) for clinical trials, we searched the literature for therapies studied by both methods. We found six therapies for which 50 RCTs and 56 HCTs were reported. Forty-four of 56 HCTs (79 percent) found the therapy better than the control regimen, but only 10 of 50 RCTs (20 percent) agreed. For each therapy, the treated patients in RCTs and HCTs of the same therapy was largely due to differences in outcome for the control groups, with HCT control patients generally doing worse than the RCT control groups. Adjustment of the outcomes of the HCTs for prognostic factors, when possible, did not appreciably change the results. The data suggest that biases in patient selection may irretrievably weight the outcome of HCts in favor of new therapies. RCTs may miss clinically important benefits because of inadequate attention to sample size. The predictive value of each might be improved by reconsidering the use of p less than 0.05 as the significance level for all types of clinical trials, and by the use of confidence intervals around estimates of treatment effects.

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  • Concato and colleagues compared randomized controlled trials with cohort studies for five somatic disorders and found that the results of observational studies were remarkably close to those of randomized controlled trials.

    “Concato and colleagues 88 compared the results of RCTs to those of cohort studies dealing with the same interventions for five different somatic disorders.Analyses of 72 metaanalyses of RCTs, 24 meta-analyses of cohort or case-control studies, and 6 meta-analyses involving both designs showed that the results of the observational studies were remarkably close to those of RCTs.”

    From The Effectiveness of Long-Term Psychoanalytic Therapy: A Systematic Review of Empirical Studies (2009) · cites this paper as [88]

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Authors
Sacks, H., Chalmers, T. C., & Smith, H.
Corresponding author
Chalmers, Thomas C..
ORCID
Venue
The American Journal of Medicine
Publisher
Elsevier BV
Published
1982-02
Volume
72
Issue
2
Pages
233-240
ISSN
0002-9343 (ISSN-L)
DOI
10.1016/0002-9343(82)90815-4
OpenAlex
W2052984045
Cited by
834
References
2
Citations by year
2026: 6 · 2025: 8 · 2024: 11 · 2023: 10 · 2022: 14 · 2021: 25 · 2020: 17 · 2019: 16 · 2018: 10 · 2017: 22 · 2016: 20 · 2015: 24 · 2014: 18 · 2013: 26 · 2012: 23
FWCI
19.36
Type
journal article
Language
en
Open access
closed
Licence
Locations
  • The American Journal of Medicine (publishedVersion)
  • PubMed (publishedVersion)
  • DigitalGeorgetown (Georgetown University Library) (submittedVersion)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
Keywords
randomized controlled trials, historical controls, clinical trial design, patient selection bias, sample size adequacy, significance level, confidence intervals, treatment effect estimation
MeSH terms
Abortion, Habitual, Anticoagulants, BCG Vaccine, Clinical Trials as Topic, Colonic Neoplasms, Coronary Disease, Diethylstilbestrol, Esophageal and Gastric Varices, Female, Fluorouracil, Humans, Melanoma, Myocardial Infarction, Pregnancy, Random Allocation

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