Making decisions about prognosis in evidence-based practice.

Prognostic studies are designed to investigate factors that impact the outcome of a disease or its treatment. These factors include, but are not limited to, inherent patient characteristics, the state of the disease, and severity of symptoms. The results of prognostic studies can be used to guide the treatment of patients with similar conditions and overall characteristics. It is the purpose of this paper to provide an outline of how to perform an unbiased appraisal of a prognostic study, allowing the physician to assess the applicability of the results to their patient and thereby assist with decision making in clinical practice.