Journal of Clinical Epidemiology
Volume 58, Issue 2 , Pages 130-137, February 2005

The generalizability of observational data to elderly patients was dependent on the research question in a systematic review

  • Cary P. Gross

      Affiliations

    • Section of General Internal Medicine, Department of Medicine, Yale-New Haven Hospital Center for Outcomes Research and Evaluation, 20 York St., New Haven, CT 06504, USA
    • Section of Cardiovascular Medicine, Department of Medicine, Yale-New Haven Hospital Center for Outcomes Research and Evaluation, 20 York St., New Haven, CT 06504, USA
    • Corresponding Author InformationCorresponding author. Yale University School of Medicine, Primary Care Center, 333 Cedar Street, PO Box 208025, New Haven, CT 06520. Tel.: 203-688-8588; fax: 203-688-4092.
    • ,
  • Pushkal P. Garg

      Affiliations

    • Division of General Internal Medicine, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
    • Department of Health Care Policy, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
    • Millennium Pharmaceuticals, Inc., 40 Landsdowne St, Cambridge, MA 02139, USA
    • ,
  • Harlan M. Krumholz

      Affiliations

    • Section of Cardiovascular Medicine, Department of Medicine, Yale-New Haven Hospital Center for Outcomes Research and Evaluation, 20 York St., New Haven, CT 06504, USA
    • Section of Health Policy and Administration, Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT 06510, USA

Accepted 9 May 2004.

Abstract 

Background and objective

Despite the increasing use of data derived from randomized controlled trials (RCTs) to perform observational studies, little is known about the validity of this approach. We compared inferences from studies that were performed using Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) RCT data with those derived from studies using data from the population-based Cooperative Cardiovascular Project (CCP).

Methods

We performed a systematic review. Articles were included if similar study questions were addressed by at least one manuscript that used GUSTO data and one that used CCP data.

Results

GUSTO findings were disparate from CCP data regarding absolute rates of specific process or outcome measures, such as thrombolysis-associated intracranial hemorrhage (ICH) (0.65% versus 1.43%, respectively), atrial fibrillation (10% versus 21%, respectively), or use of β-blockers (58% versus 37%, respectively). However, many important relations noted in GUSTO were corroborated by studies using CCP data. Both data sets identified similar predictors of ICH and presentation delay. The degree of variability in β-blocker use (across geographic region) and angiography use (between genders) was remarkably similar when studied using CCP or GUSTO data.

Conclusion

Inferences derived from GUSTO about treatment variations and risk factors for outcomes were generalizable to community patients.

Keywords: Randomized controlled trials, Global utilization of streptokinase and t-pa for occluded coronary arteries, Cooperative Cardiovascular Project, Myocardial infarction, Generalizability, Validity

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 Dr. Gross was supported by a Cancer Prevention, Control and Population Sciences Career Development Award (1K07CA-90402) and the Claude D. Pepper Older Americans Independence Center at Yale (P30AG21342). Dr. Garg is employed by Millennium Pharmaceuticals, Inc. (Cambridge, MA), which did not provide support for this study.

PII: S0895-4356(04)00250-1

doi:10.1016/j.jclinepi.2004.10.001

Journal of Clinical Epidemiology
Volume 58, Issue 2 , Pages 130-137, February 2005

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