Evidence-appraisal glossary
Prognostic Factor
A prognostic factor is a patient or disease characteristic that predicts the likely course of an illness, regardless of which treatment is given. It tells you what tends to happen, not what to do about it.
Examples include tumor stage or age forecasting survival. A prognostic factor being linked to worse outcomes does not mean that changing it, or targeting it with therapy, will help. That distinction separates prognostic factors from predictive biomarkers, which forecast who will respond to a particular treatment, and confusing the two leads to therapies aimed at markers that carry no benefit.
Read the full Reading the Evidence blog.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.