Prognosis study EBM questions

Prognostic factorsCharacteristics of patient that may predict eventual outcomeSeveral types:

demographic (eg age)disease-specific (eg tumor stage) comorbid (eg other conditions accompanying the disease in question)

Prognostic factorsCan predict any outcome, whether good (eg cure or survival) or bad (eg death or complication). Need not necessarily cause the outcomes – just be associated with them strongly enough to predict their development. Are distinguished from risk factors = patient characteristics associated with initial development of the disease Example: smoking is an important risk factor for lung cancer, but is not as important a prognostic factor as tumor stage in someone who has lung cancer.

Are the results in the study valid?Was there a representative and well-defined

sample of patients at a similar point in the course of the disease?

Was follow-up sufficiently long and complete? Were objective and unbiased outcome criteria

used? Was there adjustment for important prognostic

factors?

What are the results?

How large is the likelihood of the outcome event(s) in a specified period of time?How precise are the estimates of likelihood?

Will the results help me in caring for my patients?

Were the study patients similar to my own? Will the results lead directly to selecting or avoiding therapy? Are the results useful for reassuring or counseling patients?