EVIDENCE BASED PRACTICE BY MOHEB KHOUZAM MD EVIDENCE

EVIDENCE BASED PRACTICE BY MOHEB KHOUZAM MD

EVIDENCE BASED PRACTICE 1 - TYPES OF STUDY DESIGNS p 2 - RECOMMENDATIONS p

EVIDENCE BASED PRACTICE 1 -TYPES OF STUDY DESIGNS

1 -TYPES OF STUDY DESIGNS A. INTERVENTION STUDIES Intervention Study Level II Randomized Controlled Trials Level II 1 Controlled Trials Without Randomization

1 -TYPES OF STUDY DESIGNS RANDOMIZED CONTROLLED TRIALS (RCT) Intervention p Prospective p Random method p Experimental and control groups p

1 -TYPES OF STUDY DESIGNS CONTROLLED TRIALS WITHOUT RANDOMIZATION Intervention p Prospective p No randomization p Experimental & control groups p

1 -TYPES OF STUDY DESIGNS B-OBSERVATIONAL STUDIES Observational Studies Level II-2 a COHORT (Relative Risk) Level II-2 b CASE CONTROL (Odds Ratio) Level II-3 Level III

1 -TYPES OF STUDY DESIGNS COHORT STUDIES p p p Exposure status known Follow-up for a period of time Determine presence or absence of disease n n p (i) Prospective: groups of exposed & unexposed followed -up for a period to determine outcome (ii) Retrospective: both exposures & outcomes occurred. Rate of disease in exposed / Rate of disease in unexposed gives Relative Risk

1 -TYPES OF STUDY DESIGNS CASE CONTROLLED STUDIES p p p p Retrospective Group of subjects with specific outcome (cases) Group of subjects without specific outcome (controls) Over a period of time Here starting point is disease status Compare extent of exposure to a variable of interest Odds of exposure in cases/odd of exposure in controls= Odds Ratio

1 -TYPES OF STUDY DESIGNS B- OBSERVATIONAL STUDY Level II-3 Cross Sectional (Prevalence) Uncontrolled Investigational

1 - TYPES OF STUDY DESIGNS CROSS SECTIONAL STUDIES p Observational p Assess the status of individuals with respect to presence or absence of both exposure & outcome at a particular time. p p Prevalence is the proportion of individuals with a disease at a particular time Incidence is the number of new cases occurring over a specified period of time

1 -TYPES OF STUDY DESIGNS UNCONTROLLED INVESTIGATIONAL STUDIES Observational p Report the results of treatment or interventions in a particular group p No control group p

1 -TYPES OF STUDY DESIGNS B- OBSERVATIONAL STUDY Level III Descriptive (Case Report/Series) Expert Opinion

1 -TYPES OF STUDY DESIGNS DESCRIPTIVE STUDIES p Provide limited information on relationship between exposure and outcome of interest p Case study describes clinical characteristics or interesting features in a single patient p Case series describes the same in a series of patients

1 -TYPES OF STUDY DESIGNS EXPERT OPINION p Findings from expert panels and committees and the opinions of respected experts in a particular field

1 -TYPES OF STUDY DESIGNS A, B, C-OTHERS Other Studies Decision Analysis Meta-Analysis Cost-Benefit Cost Effectiveness

1 -TYPES OF STUDY DESIGNS DECISION ANALYSIS Death Operative complications Total Cure Uneventful Hysterectomy Long Term disability Uneventful Subtotal Operative complications Cure Death Long Term disability Cure Decision Tree, branches are key problems or decisions Driven by key assumptions

1 -TYPES OF STUDY DESIGNS p META-ANALYSIS • Beers • Dipalo • Henry • Zo p p Effect on endometrial cancer: smoking vs. no smoking Weighted average of a variable/intervention on a defined outcome

1 -TYPE OF DESIGN STUDIES COST-BENEFIT ANALYSIS p Compares costs associated with an intervention with the net monetary benefits from the use of that intervention

1 -TYPES OF STUDY DESIGNS COST-EFFECTIVENESS ANALYSIS p Compares the net monetary costs of an intervention with some measure of clinical outcome

2 -RECOMMENDATIONS BASED ON QUALITY & QUANTITY OF EVIDENCE Recommendations A B C D E

2 -RECOMMENDATIONS p p p A There is good evidence to support recommendations B There is fair evidence to support recommendations C There is insufficient evidence to support recommendations, but recommendation is made on other grounds D There is fair evidence against recommendations E There is good evidence against recommendations There is no exact correlation between strength of recommendations and level of evidence