Update on the Methods of the U.S. Preventive Services Task Force: Linking Intermediate Outcomes and Health Outcomes...

Area of Science:

• Clinical Preventive Services
• Evidence-Based Medicine
• Health Outcomes Research

Background:

• The U.S. Preventive Services Task Force (USPSTF) provides evidence-based recommendations for clinical preventive services.
• Recommendations require evidence of a service's impact on health outcomes, defined as effects on quality or quantity of life.

Purpose of the Study:

• To review the USPSTF's historical use of intermediate outcomes in developing recommendations.
• To assess the reliability of evidence linking intermediate outcomes to health outcomes.

Main Methods:

• Review of USPSTF's historical practices.
• Analysis of methods used by other evidence-based guideline bodies.
• Consultation with experts and review of scientific literature.
• Application of criteria for causation and principles of evidence-based medicine.

Main Results:

• Intermediate outcomes are frequently used when direct health outcome evidence is lacking.
• Studies examining intermediate outcomes can provide useful, though potentially confounded, information.
• Establishing a consistent relationship between intermediate and health outcomes is challenging.

Conclusions:

• The USPSTF acknowledges the limitations of evidence linking intermediate outcomes to health outcomes.
• Great caution is exercised when recommendations rely on such evidence due to inherent limitations.
• Ensuring the ultimate goal of predictable changes in health outcomes is paramount.