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XIX. Applying Clinical Trial Results

B. Guidelines for Determining Whether a Drug Is Exerting (More Than) a Class Effect

Finlay A. McAlister, MD, FRCPC; Andreas Laupacis, MD, MSc, FRCPC; George A. Wells, MSc, PhD; David L. Sackett, FRSC, MD, FRCP; for the Evidence-Based Medicine Working Group

JAMA. 1999;282:1371-1377.

	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

INTRODUCTION

Most classes of drugs include multiple compounds. The opinions of clinicians, manufacturers, and purchasers may differ as to whether a particular drug is more efficacious, safer, or more cost-effective than others in its class.¹ In this article, we review the types of evidence commonly cited to support the prescribing of a particular drug rather than another of the same class and provide a hierarchy for grading studies that compare a drug with another of the same class, expanding on our discussion in part A of this Users' Guide.²

CLINICAL SCENARIOS

The Clinician

As a clinician, you care for many patients with elevated serum cholesterol levels. A speaker at a recent continuing medical education event reviewed the benefits of cholesterol-lowering therapy, particularly with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors . . . [Full Text of this Article]

The Policymaker

DRUG CLASSES

Risks of Assuming a Class Effect

Levels of Evidence

Level 1

Level 2

Level 3

Level 4

Other Considerations

Amount of Efficacy Evidence

Safety

Convenience/Compliance

Cost

RESOLUTION OF SCENARIOS

The Clinician

The Policymaker

CONCLUSION

Author Affiliations: National Health Service Research and Development Centre for Evidence-Based Medicine, John Radcliffe Hospital, Oxford, England (Drs McAlister and Sackett); Division of General Internal Medicine, Ottawa Hospital (Dr Laupacis), and Clinical Epidemiology Unit, Loeb Health Research Institute (Drs Laupacis and Wells), Ottawa, Ontario.

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