Diagnostic and treatment decisions in US healthcare.

The practice of medicine links diagnosis to treatment. However, for many diagnosed conditions diagnosis and treatment may not affect health outcome. Examples include low-grade cancers that do not influence life expectancy or quality of life. Further, there is considerable uncertainty about the point along a biologic continuum where treatment should begin. Changes in diagnostic thresholds often increase healthcare costs even though the benefit of the treatment is uncertain. Although this uncertainty is understood by the healthcare providers, it often is not shared with patients. We advocate a new paradigm called shared medical decision making that makes uncertainty about diagnosis and treatment transparent to patients and engages them in the treatment decision process.