3) Basics of Evidence-Based Practice

1. systems

2. summaries

3. synopses of syntheses

4. syntheses

5. synopses of single studies

6. single studies

what is the 6S pyramid

systems

• computerized decision support systems

• computer takes entire bit of evidence into and analyzes it in order to answer clinical decisions

summaries

• evidence-based clinical practice guidelines

• team of experts analyze it and come up with specific recommendations for clinical practice

synopses of syntheses

summaries of systematic reviews

syntheses

• systematic reviews

• team of researchers have systematically combed through the lit, identified relevance, analyzed, and given effect

• combine a lot of evidence and provide overall picture

synopses of single studies

summaries of individual studies

single studies

• individual studies

• researching w a single or group of patients

• primary - individual for specific studies

• secondary - someone else has already done the work to verify the evidence to help us make a better decisions

primary vs secondary or pre appraised evidence

secondary

is secondary or primary a more convenient way to incorporate evidence into practice

• RCTs

• cohort studies

• case control studies

• cross sectional studies

• case reports/case studies

types of individual studies

randomized controlled trial - EXPERIMENTAL

• randomly assigning ppl to get diff treatments DO = experimental DO NOT = control

• compares A to B (exercise to no exercise in random groups) to minimize bias and get closer to truth

cohort study - observational

• one or more groups followed over time, prospectively and retrospectively

• (one group chooses to exercise and other chooses not to)

• intervention (not random)

prospective bc higher quality due to human memory flaws and from reasons for choice (personal or environmental)

which is stronger: prospective or retrospective

case control - observation

• comparison of groups WITH cases or WITHOUT controls the outcome of interest, generally retrospective (backwards in time)

• group w pain & group w/out pain and ask about exercises and compare differences

• outcome

cross sectional study - observational

• comparison of subjects at a single point in time

case reports or case series - observational

• WEAK but useful to describe interventions and first step in understanding effect

• retrospective description of clinical practice

• single or limited # of patients

quesiton

the “best evidence” depends on the

experimental studies/randomized control trials

for questions about the effectiveness of INTERVENTIONS, look for ______ bc it does the best job at minimizing bias and establish a cause and effect relationship btw intervention and outcome of interest

PROSPECTIVE cohort studies

for questions about PROGNOSIS and prognostic factors, look for _____ bc it demonstrates a good vs bad prognosis

cross-sectional studies

for questions about TESTS AND MEASURES look for ______ bc of how reliable they are at the single point in time… due to a particular test or measure?

• experimental/randomized controlled trial

• prospective cohort studies

• retrospective cohort or case control studies

• case control studies

• cross sectional studies

• case reports/case studies

• expert opinion - no research based evidence to support

ranking of strength of evidence

background and foreground

what are the 2 types of clinical questions

background questions

• GENERAL information about a condition, test, impairment, etc.

• use textbook, Google, or professor to answer

foreground questions

• facilitate clinical decision making about specific tests or measures, prognostic factors, or interventions

• a lot more specific about demographic and outcome seeking an answer

PICO! - patient, intervention (test or prognostic factor,) comparison (btw A or B treatment,) outcome (the goal or improvement we want)

what acronym or tool can we use to formulate a foreground question

in an 86 y/o woman w hospital acquired reconditioning, will balance exercises and resistance training lead to a greater reduction in fall risk than resistance training alone?

formulate a foreground ? from this information

• 86 y/o patient w hospital-acquired deconditioning

• balance and resistance training intervention

• comparing to resistance training alone

• goal to reduce fall risk

1. formulate your clinical question and identify your search terms

2. start your search at the top of the evidence pyramid

3. choose your database based on the scope and features

4. use search teams and database features to narrow or broaden your search as necessary

rules for searching for evidence

MeSH

medical subject headings

• summary/clinical practice guideline

• then look for synthesis/systematic review next

• then look for an individual study

MOVING DOWN THE PYRAMID FROM SYSTEMS → SINGLE STUDIES

starting at the top of the pyramid, look for a

1. is the evidence applicable to my clinical question

2. is this evidence of sufficient quality

3. how should we interpret the results

3 questions to appraise evidence

question 1

• is the participant similar to my patient? — are they of same demographic or condition to respond similarly to their study?

• are the interventions and outcome measures easy to be replicated in my setting?

question 2

• was bias minimized in the design and conduct of the study

question 3

• for the outcomes of interest how large was the effect or change in the performance

minimum detectible change

smallest amount of change that can be detected by a measure that corresponds to a noticeable change in ability

minimal clinically important difference

smallest amount of change in an outcome that might be considered important by the pt or clinician