Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Review Article
  • Published:

From randomized trials to registry studies: translating data into clinical information

Nature Clinical Practice Cardiovascular Medicine volume 5, pages 613–620 (2008)Cite this article

Abstract

All clinicians face the challenge of practicing evidence-based medicine and are confronted with data from a variety of studies, ranging from prospective randomized and registry studies to retrospective analyses. Unfortunately, the data frequently provide conflicting recommendations. How then should one interpret the information so that study findings can be applied directly in patient care? To evaluate the relevance of the abundance of studies published and how they apply to an individual patient, physicians must understand subtle nuances of study design and their effect on the interpretation of the results. In this Review, we examine the strengths and weaknesses of different study designs with the aim of providing the reader with a greater understanding how best to apply study results in the clinical setting.

Key Points

  • The practice of 'evidence-based medicine' is challenging, as the results of randomized and observational studies can seem conflicting

  • Randomization distributes both known and unknown confounders between treatment groups such that at baseline the groups will differ only by chance, while observational studies can be adjusted only for known confounders

  • Strict inclusion and exclusion criteria mean that the results of randomized studies might not be as applicable to general populations as are findings from observational studies, including both clinical registries and retrospective reviews

  • In the clinical application of the results of any study to the treatment of an individual patient, the clinician must be cognizant of statistical power and the subtle implications of combined end points and surrogate outcomes

  • Peer review has a critical role in assuring the legitimacy of data presented and of conclusions stated in a manuscript, but cannot assure the validity of conclusions drawn by the reader or substitute for an informed analysis

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

References

  1. Pereira AC et al. (2006) Clinical judgment and treatment options in stable multivessel coronary artery disease: results from the one-year follow-up of the MASSII (Medicine, Angioplasty, or Surgery Study II). J Am Coll Cardiol 48: 948–953

    Article  Google Scholar 

  2. King SB 3rd et al. for the Emory Angioplasty versus Surgery Trial Investigators (1997) Angioplasty or surgery for multivessel coronary artery disease: comparison of eligible registry and randomized patients in the EAST trial and influence of treatment selection on outcomes. Am J Cardiol 79: 1453–1459

    Article  Google Scholar 

  3. Mercado N et al. (2005) One-year outcomes of coronary artery bypass graft surgery versus percutaneous coronary intervention with multiple stenting for multisystem disease: a meta-analysis of individual patient data from randomized clinical trials. J Thorac Cardiovasc Surg 130: 512–519

    Article  Google Scholar 

  4. Jones RH et al. (1996) Long-term survival benefits of coronary artery bypass grafting and percutaneous transluminal angioplasty in patients with coronary artery disease. J Thorac Cardiovasc Surg 111: 1013–1025

    Article  CAS  Google Scholar 

  5. Hannan EL et al. (2005) Long-term outcomes of coronary-artery bypass grafting versus stent implantation. N Engl J Med 352: 2174–2183

    Article  CAS  Google Scholar 

  6. Steg PG et al. for the GRACE Investigators (2007) External validity of clinical trials in acute myocardial infarction. Arch Intern Med 167: 68–73

    Article  Google Scholar 

  7. Detre KM et al. (1999) Coronary revascularization in diabetic patients: a comparison of the randomized and observational components of the Bypass Angioplasty Revascularization Investigation (BARI). Circulation 99: 633–640

    Article  CAS  Google Scholar 

  8. Mack MJ et al. (2004) Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease. J Thorac Cardiovasc Surg 127: 167–173

    Article  Google Scholar 

  9. van Dijk D et al. for the Octopus Study Group (2007) Cognitive and cardiac outcomes 5 years after off-pump vs on-pump coronary artery bypass graft surgery. JAMA 297: 701–708

    Article  CAS  Google Scholar 

  10. Berger PB et al. for the BARI investigators (2001) Survival following coronary angioplasty versus coronary artery bypass surgery in anatomic subsets in which coronary artery bypass surgery improves survival compared with medical therapy: results from the Bypass Angioplasty Revascularization Investigation (BARI). JACC 38: 1440–1449

    Article  CAS  Google Scholar 

  11. Granger CB et al. for the COMMA Investigators (2003) Pexelizumab, an anti-C5 complement antibody, as adjunctive therapy to primary percutaneous coronary intervention in acute myocardial infarction: the COMplement inhibition in Myocardial infarction treated with Angioplasty (COMMA) trial. Circulation 108: 1184–1190

    Article  CAS  Google Scholar 

  12. Armstrong PW et al. for the APEX AMI Investigators (2007) Pexelizumab for acute ST-elevation myocardial infarction in patients undergoing primary percutaneous coronary intervention: a randomized controlled trial. JAMA 297: 43–51

    Article  CAS  Google Scholar 

  13. Hammermeister K et al. (2000) Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial. J Am Coll Cardiol 36: 1152–1158

    Article  CAS  Google Scholar 

  14. Fleming TR and DeMets DL (1996) Surrogate end points in clinical trials: are we being misled? Ann Intern Med 125: 605–613

    Article  CAS  Google Scholar 

  15. Connolly SJ (2006) Use and misuse of surrogate outcomes in arrhythmia trials. Circulation 113: 764–766

    Article  Google Scholar 

  16. Cleland JG et al. (2006) Longer-term effects of cardiac resynchronization therapy on mortality in heart failure [the CArdiac REsynchronization-Heart Failure (CARE-HF) trial extension phase]. Eur Heart J 27: 1928–1932

    Article  Google Scholar 

  17. Bigger JT Jr (1985) Patients with malignant or potentially malignant ventricular arrhythmias: opportunities and limitations of drug therapy in prevention of sudden death. J Am Coll Cardiol 5 (Suppl 6): 23B–26B

    Article  Google Scholar 

  18. CAST investigators (1989) The cardiac arrhythmia suppression trial. N Engl J Med 321: 1754–1756

  19. Kastrati A et al. (2007) Analysis of 14 trials comparing sirolimus-eluting stents with bare-metal stents. N Engl J Med. 356: 1030–1039

    Article  CAS  Google Scholar 

  20. Montori VM et al. (2005) How should clinicians interpret results reflecting the effect of an intervention on composite endpoints: should I dump this lump? ACP J Club 143: A8

    PubMed  Google Scholar 

  21. Freemantle N et al. (2003) Composite outcomes in randomized trials: greater precision but with greater uncertainty? JAMA 289: 2554–2559

    Article  Google Scholar 

  22. Stone GW et al. for the TAXUS-IV Investigators (2004) One-year clinical results with the slow-release, polymer-based, paclitaxel-eluting TAXUS stent: the TAXUS-IV trial. Circulation 109: 1942–1947

    Article  CAS  Google Scholar 

  23. The ISIS-2 Investigators for the ISIS-2 (Second International Study of Infarct Survival) Collaborative Group (1988) Randomized trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. Lancet 2: 349–360

  24. Benos DJ et al. (2003) How to review a paper. Advan Physiol Edu 27: 47–52

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. ML Brown is a Research Fellow in the Division of Cardiovascular Surgery, BJ Gersh and DR Holmes are Professors of Medicine in the Division of Cardiovascular Medicine, KT Bailey is Associate Professor in the Division of Biostatistics, and TM Sundt III is Professor of Surgery in the Division of Cardiovascular Surgery, all at Mayo Clinic, Rochester, MN, USA.,

    Morgan L Brown, Bernard J Gersh, David R Holmes, Kent R Bailey & Thoralf M Sundt III

Authors
  1. Morgan L Brown
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Bernard J Gersh
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. David R Holmes
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kent R Bailey
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Thoralf M Sundt III
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Thoralf M Sundt III.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brown, M., Gersh, B., Holmes, D. et al. From randomized trials to registry studies: translating data into clinical information. Nat Rev Cardiol 5, 613–620 (2008). https://doi.org/10.1038/ncpcardio1307

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ncpcardio1307

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing