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The “CONSORT” guidelines for randomized controlled trials in Obstetrics & Gynecology
The “CONSORT” Guidelines for Randomized Controlled Trials in Obstetrics & Gynecology
David A. Grimes, MD Consultant Editor
Both the randomized controlled trial and this journal came into being shortly after World War II. Although clinical experiments date back to 600 BC,1 the first randomized controlled trial was published in 1948.2 The fledgling American College of Obstetricians and Gynecologists launched publication of Obstetrics & Gynecology 5 years later. Over the past half century, the importance of the randomized controlled trial and this journal has grown in parallel. In recent years, one in ten articles published in Obstetrics & Gynecology has used this research design.3 The unique contribution of the randomized controlled trial is avoiding the biases inherent in most observational research. To do this, however, the trial must be properly done. Regrettably, most trials are not. For example, some authors use techniques to develop “randomization” sequences that are not random—for example, alternate assignment or days of the week to allocate participants.4 Failure to conceal the upcoming assignment from those involved with trial recruitment leads to selection bias, which exaggerates the treatment effect.5 Dropping from analysis those participants who did not comply with their assigned treatment is common, but wrong.6 Similarly, excluding from analysis those participants eventually found to have been ineligible for the trial is frequently done—intuitively appealing, but also incorrect. Large losses to follow-up often undermine the stated conclusions of trial reports.6 Most published reports in obstetric and gynecologic journals violate the rules of conduct.4 However, the problem of poor quality research is generic.7 Why, after a half century of experience, is the quality of randomized controlled trials so poor? One ready explanation is naı¨vete´: Many investigators today have no formal training in research methods.7,8 Fortunately, help is now readily available. In 2001, the second version of the CONSORT (Consolidated Standards for Reporting of Trials) guidelines was simultaneously published in three general medical journals.9 These guidelines, developed by experienced researchers and editors and based on evidence whenever possible, provide the rules for the conduct and reporting of randomized controlled trials. A background article, documenting the evidence supporting the guidelines and providing examples from the literature, contains over 200 citations.10 An abbreviated checklist is available from this journal’s Web site.11 The CONSORT guidelines encourage authors to submit with their manuscript a participant flowchart, which enables reviewers, editors, and, ultimately, readers to evaluate whether appropriate methods were followed. The flowchart documents the disposition of every participant who entered the trial, so that inappropriate exclusions, high loss-to-follow-up rates, and other potential problems can be detected. Many journals, including Obstetrics & Gynecology, have adopted the CONSORT guidelines for reports of randomized controlled trials. But will adherence to the CONSORT guidelines lead to better science? One cohort study has shown that journals that adopted the CONSORT guidelines had a more rapid improvement in trial quality than did another prominent journal that did not adopt them.12 Thus, evidence suggests that the CONSORT guidelines can make a difference. However,
VOL. 100, NO. 4, OCTOBER 2002 © 2002 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc.
0029-7844/02/$22.00 PII S0029-7844(02)02233-0
631
the rigor with which editors encourage (or enforce) compliance with the guidelines varies. Randomized controlled trials take considerable effort. The rewards, however, are commensurate. Rigorous methods complemented by full and clear reporting will pay big dividends. The proper research methods are explicit; we must now ensure they are followed. Lack of awareness of proper methods can no longer be an excuse for substandard trials.8 Altman13 has argued that poor quality research is as unethical as fraudulent research. Both have the same net effect: wrong answers to important clinical questions. The medical community has taken a forceful stand against fraud14; we now need the same commitment to avoid poor quality trials.
REFERENCES 1. Grimes DA. Clinical research in ancient Babylon: Methodologic insights from the book of Daniel. Obstet Gynecol 1995;86:1031– 4. 2. Streptomycin in Tuberculosis Trials Committee. Streptomycin treatment of pulmonary tuberculosis. BMJ 1948;2: 769 – 82. 3. Funai EF, Rosenbush EJ, Lee MJ, Del Priore G. Distribution of study designs in four major US journals of obstetrics and gynecology. Gynecol Obstet Invest 2001;51: 8 –11. 4. Schulz KF, Chalmers I, Grimes DA, Altman DG. Assessing the quality of randomization from reports of controlled trials published in obstetrics and gynecology journals. JAMA 1994;272:125– 8.
632
Grimes
CONSORT Guidelines for Randomized Controlled Trials
5. Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials. JAMA 1995;273:408 –12. 6. Schulz KF, Grimes DA. Sample size slippages in randomised trials: Exclusions and the lost and wayward. Lancet 2002;359:781–5. 7. Altman DG. Poor-quality medical research: What can journals do? JAMA 2002;287:2765–7. 8. Grimes DA, Schulz KF. Methodology citations and the quality of randomized controlled trials in obstetrics and gynecology. Am J Obstet Gynecol 1996;174:1312–5. 9. Moher D, Schulz KF, Altman D. The CONSORT statement: Revised recommendations for improving the quality of reports of parallel-group randomized trials. JAMA 2001;285:1987–91. 10. Altman DG, Schulz KF, Moher D, Egger M, Davidoff F, Elbourne D, et al. The revised CONSORT statement for reporting randomized trials: Explanation and elaboration. Ann Intern Med 2001;134:663–94. 11. Standards for reporting randomized trials. Available at: http://www.greenjournal.org/CONSORT.pdf. Accessed 2002 Jul 29. 12. Moher D, Jones A, Lepage L. Use of the CONSORT statement and quality of reports of randomized trials: A comparative before-and-after evaluation. JAMA 2001;285: 1992–5. 13. Altman DG. The scandal of poor medical research. BMJ 1994;308:283– 4. 14. Buyse M, George SL, Evans S, Geller NL, Ranstam J, Scherrer B, et al. The role of biostatistics in the prevention, detection and treatment of fraud in clinical trials. Stat Med 1999;18:3435–51.
OBSTETRICS & GYNECOLOGY
David A. Grimes, MD Consultant Editor
Both the randomized controlled trial and this journal came into being shortly after World War II. Although clinical experiments date back to 600 BC,1 the first randomized controlled trial was published in 1948.2 The fledgling American College of Obstetricians and Gynecologists launched publication of Obstetrics & Gynecology 5 years later. Over the past half century, the importance of the randomized controlled trial and this journal has grown in parallel. In recent years, one in ten articles published in Obstetrics & Gynecology has used this research design.3 The unique contribution of the randomized controlled trial is avoiding the biases inherent in most observational research. To do this, however, the trial must be properly done. Regrettably, most trials are not. For example, some authors use techniques to develop “randomization” sequences that are not random—for example, alternate assignment or days of the week to allocate participants.4 Failure to conceal the upcoming assignment from those involved with trial recruitment leads to selection bias, which exaggerates the treatment effect.5 Dropping from analysis those participants who did not comply with their assigned treatment is common, but wrong.6 Similarly, excluding from analysis those participants eventually found to have been ineligible for the trial is frequently done—intuitively appealing, but also incorrect. Large losses to follow-up often undermine the stated conclusions of trial reports.6 Most published reports in obstetric and gynecologic journals violate the rules of conduct.4 However, the problem of poor quality research is generic.7 Why, after a half century of experience, is the quality of randomized controlled trials so poor? One ready explanation is naı¨vete´: Many investigators today have no formal training in research methods.7,8 Fortunately, help is now readily available. In 2001, the second version of the CONSORT (Consolidated Standards for Reporting of Trials) guidelines was simultaneously published in three general medical journals.9 These guidelines, developed by experienced researchers and editors and based on evidence whenever possible, provide the rules for the conduct and reporting of randomized controlled trials. A background article, documenting the evidence supporting the guidelines and providing examples from the literature, contains over 200 citations.10 An abbreviated checklist is available from this journal’s Web site.11 The CONSORT guidelines encourage authors to submit with their manuscript a participant flowchart, which enables reviewers, editors, and, ultimately, readers to evaluate whether appropriate methods were followed. The flowchart documents the disposition of every participant who entered the trial, so that inappropriate exclusions, high loss-to-follow-up rates, and other potential problems can be detected. Many journals, including Obstetrics & Gynecology, have adopted the CONSORT guidelines for reports of randomized controlled trials. But will adherence to the CONSORT guidelines lead to better science? One cohort study has shown that journals that adopted the CONSORT guidelines had a more rapid improvement in trial quality than did another prominent journal that did not adopt them.12 Thus, evidence suggests that the CONSORT guidelines can make a difference. However,
VOL. 100, NO. 4, OCTOBER 2002 © 2002 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc.
0029-7844/02/$22.00 PII S0029-7844(02)02233-0
631
the rigor with which editors encourage (or enforce) compliance with the guidelines varies. Randomized controlled trials take considerable effort. The rewards, however, are commensurate. Rigorous methods complemented by full and clear reporting will pay big dividends. The proper research methods are explicit; we must now ensure they are followed. Lack of awareness of proper methods can no longer be an excuse for substandard trials.8 Altman13 has argued that poor quality research is as unethical as fraudulent research. Both have the same net effect: wrong answers to important clinical questions. The medical community has taken a forceful stand against fraud14; we now need the same commitment to avoid poor quality trials.
REFERENCES 1. Grimes DA. Clinical research in ancient Babylon: Methodologic insights from the book of Daniel. Obstet Gynecol 1995;86:1031– 4. 2. Streptomycin in Tuberculosis Trials Committee. Streptomycin treatment of pulmonary tuberculosis. BMJ 1948;2: 769 – 82. 3. Funai EF, Rosenbush EJ, Lee MJ, Del Priore G. Distribution of study designs in four major US journals of obstetrics and gynecology. Gynecol Obstet Invest 2001;51: 8 –11. 4. Schulz KF, Chalmers I, Grimes DA, Altman DG. Assessing the quality of randomization from reports of controlled trials published in obstetrics and gynecology journals. JAMA 1994;272:125– 8.
632
Grimes
CONSORT Guidelines for Randomized Controlled Trials
5. Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials. JAMA 1995;273:408 –12. 6. Schulz KF, Grimes DA. Sample size slippages in randomised trials: Exclusions and the lost and wayward. Lancet 2002;359:781–5. 7. Altman DG. Poor-quality medical research: What can journals do? JAMA 2002;287:2765–7. 8. Grimes DA, Schulz KF. Methodology citations and the quality of randomized controlled trials in obstetrics and gynecology. Am J Obstet Gynecol 1996;174:1312–5. 9. Moher D, Schulz KF, Altman D. The CONSORT statement: Revised recommendations for improving the quality of reports of parallel-group randomized trials. JAMA 2001;285:1987–91. 10. Altman DG, Schulz KF, Moher D, Egger M, Davidoff F, Elbourne D, et al. The revised CONSORT statement for reporting randomized trials: Explanation and elaboration. Ann Intern Med 2001;134:663–94. 11. Standards for reporting randomized trials. Available at: http://www.greenjournal.org/CONSORT.pdf. Accessed 2002 Jul 29. 12. Moher D, Jones A, Lepage L. Use of the CONSORT statement and quality of reports of randomized trials: A comparative before-and-after evaluation. JAMA 2001;285: 1992–5. 13. Altman DG. The scandal of poor medical research. BMJ 1994;308:283– 4. 14. Buyse M, George SL, Evans S, Geller NL, Ranstam J, Scherrer B, et al. The role of biostatistics in the prevention, detection and treatment of fraud in clinical trials. Stat Med 1999;18:3435–51.
OBSTETRICS & GYNECOLOGY