QUESTIONS TO ASK IN PROGNOSTIC STUDIESOnofre Morn MD, MSc.Professor, Faculty of Medicine, Universidad Autnoma de San Luis Potos, S.L.P. Mxico.PhD CandidateUniversity of British Columbia, Vancouver, Canada.

Questions to ask in Prognostic studiesWHY:Justified?Hypothesis/purpose of the study?

HOW:Was an inception cohort assembled?Were objective outcome criteria used?Was the outcome assessment blind?Were DIAGNOSTIC SUSPICION BIAS and EXPECTATION BIAS avoided?

Questions to ask in Prognostic studiesWHO:Is the studied sample CLEARLY described?Is the referral pattern described? Is there evidence of REFERRAL FILTER BIAS or DIAGNOSTIC ACCESS BIAS?Do the authors account for every patient who was eligible for the study but did NOT enter it?Was complete follow-up achieved?

Questions to ask in Prognostic studiesWHAT:Was adjustment for known prognostic factors carried out (THERAPEUTIC ACCESS BIAS)?Was there LEAD TIME BIAS considered?Were losses to follow-up handled appropriately and was their clinical status determined?Were all clinically relevant outcomes reported?

Questions to ask in Prognostic studiesHOW MANY?Was statistical significance considered?Were statistical test applied appropriately? Was any measurement of risk provided?Was the study large enough to detect important outcomes?If no increased risk was found, was there any consideration of the power of the study?

Questions to ask in Prognostic studiesSO WHAT?Are the results clinically significant?Are the results (and patients) sufficiently described to be generalized to the clinical practice?Is the therapeutic intervention feasible in your practice?

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