i have a clinical question … evidence-based practice questions handout - 6 slides... ·...

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Evidence-Based PracticeAccessing/Understanding the Current Literature

Ed Mulligan, PT, DPT, OCS, SCS, ATC

Clinical Orthopedic Rehabilitation Education

Evidence-Based PracticeAccessing/Understanding the Current Literature

Ed Mulligan, PT, DPT, OCS, SCS, ATC

Clinical Orthopedic Rehabilitation Education

I have a clinical question … how could I research the answer

Sackett’s Definition

“The conscientious, explicit, and judicious use of

Evidence-Based Practice

Why is it important?

integration of evidence into our clinical decision‐making should enhance outcomes and reduce unwarranted variation in practice

the current best evidence in making decisions about the care of patients”

Standards of Care are Good!

Best‐practice guidelines for clinical care should be a clinician’s obligation to consider but not necessarily s persede the other tenets of e idence based caresupersede the other tenets of evidence‐based care

IMO, it’s better to be consciously ineffective than to be unconsciously ineffective

BEST EVIDENCELiterature Resources

What are the Elements of Evidence Based Practice?

VALUESPatient Expectations

EXPERIENCE Provider Expertise

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What evidence practice is NOT …

A cookbook approach– Evidence is always tempered by the patient’s unique

circumstance and needscircumstance and needs

A replacement for experience and expertise

Solely a reflection of RCTs and meta-analyses

A cost-cutting measure– Hopefully, it identifies both efficacy

(does it work) … and efficiency (how well it works)

What evidence practice is NOT …

G ide to Ph sical Therapist PracticeGuide to Physical Therapist Practice This is an example of expert consensus,

not evidence‐based information

What Evidence is …

Data/information which tends to prove or disprove a construct

D t /i f ti th t k Data/information that makes something more plain or clear

and, the best evidence is free of bias

Unfortunate evidence perspectives

“Copy from one, it's plagiarism; copy from two, it's research; copy from three and it’s a fact of practice”

“The plural of anecdotes is evidence” (if enough people think it or say it – it must be true)

“In God we trust –everyone else must bring data”

The Journal of Mental Manipulation’s most recent issue reported on the

clinical superiority of a new manual therapy technique referred to as

“tactile hallucination”. Rehabilitation clinicians are flocking to continuing

education programs to learn this exciting new technique which appears to

be applicable for conditions ranging from hangnails to hernias. Only expert

clinicians trained abroad are qualified to teach these techniques at resort

locations during the work week. Many physicians are prescribing this

therapeutic technique based on the testimonials from their patientstherapeutic technique based on the testimonials from their patients.

Scientific investigation of the technique have proven to be unnecessary

because of the fantastic results reported through infomercials, reputable

media outlets such as the advertisement section in the back of Runner’s

World, Daytime talk shows and People magazine. For more information on

this exciting development in rehabilitation, visit the originator’s web site

(www.neednoproof.com) or watch their infomercial airing on Channel 76

(WDUH) at 4:30 am on Saturday, April 1st.

Without apology – “I am not a Guru”as evidenced by the John Child’s “guru litmus test” on his Evidence in Motion blog

o I am not a great salesman

o Personable, charming, charismatic, and persuasive

o I will not offer miraculous or cure-all approaches

The problem with expert opinion … you are often bestowed guru status

o I will not offer miraculous or cure all approaches

o I do not have any proprietary language

o I’m still trying to come up with an original idea

o You are not my students (but my colleagues)

o I do not have any techniques named after myself – I’m not that “Mulligan”

o I try to apply EBP materials

o What has been Proven, Not Proven, & Proven Not

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What is the public’s attitude about utilization of EBP?

“You just have to be very inquisitive,” he said.

“The physical therapist should be able to explain the various treatment options. You should ask about the benefits and risks, and ask what is the evidence that it will work.”

And if the therapist can’t give you good answers, he added, you might want to rethink your choice of therapist.

EBP Attitudes and Utilization

Our actions are so loud maybe the medical community and public can’t hear the words we’re sa ingsaying

The days of assuming financial risk for our outcomes are imminent

Here’s some anecdotal evidence regarding our attitudes

Overflowing auditorium audience necessitating a repeat lecture the next day for “Barefoot Running”

Less than 50 people in attendance in a nearly empty auditorium for a lecture titled “Attitudes and

Beliefs of Physical Therapists about Evidence-Based Practice:How Do We Facilitate the Translation of Evidence into Practice Behaviors?

What is the attitude towards EBP?

90% necessary

90% don’t think it causes unreasonable demand

80% useful

80% improves care

70% assists decision making

Jette, et al, Phys Ther 2003

What type of therapist uses EBP?

Characteristics that best predicted practitioners that employ EPB

– Desire for learningg– Higher academic degree– Value practicality and non-conformity

Variables that had a negative correlation with use of EBP

– Older age and increased years of practice– Decreased % of time in direct patient care

Bridges PH, et al, BMC Health Services Research, 2007

“It’s time to stop studying our habits and attitudes about EPB – and time to start doing it.”

Gerald Brennan, CSM, 2011

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It starts with reading to find the evidence Journal Reading Habit

Survey of 544 clinicians from a large corporate outpatient setting read an average of 2.44 journal articles/montharticles/month

– Distribution was skewed to the left

– Measure of central tendency hovered around 1

Mode and median = 1

– 68% read 0 or 1 articles/month

– 7% read 6 or more articles/month

165 1146 0123 290 315 4

On a scale of 0-5 with 0 representing no expertise and 5 representing utmost competency, how would you rate your current knowledge and exper

180

170

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150

140

130

120

30.6 %

27.1 %

22.8 %

Clinicians self rating of research expertise

Mean = 1.37Mean = 1.37

1100

1 0 2 3 4

120

110

100

90

80

70

60

50

40

30

20

10

0

16.7 %

2.8 %

433

2200

Rating % %

0 27 57 Novice

Clinicians self rating of research expertise

57 Novice1 302 233 174 3 3 Expert5 0

142 2124 3121 185 060 411 5

On a scale of 0-5 with 0 representing no expertise and 5 representing utmost competency, how would you rate your comfort in researching a clini

150

140

130

120

110

26.2 %

22.8 %22.3 %

Mean = 1.97Mean = 1.97

Clinicians self rating of comfort with researching a clinical question to ensure an evidence-based perspective

2233 1

2 3 1 0 4 5

100

90

80

70

60

50

40

30

20

10

0

15.7 %

11.0 %

2.0 %

33 1

004 5

Rating % %

0 16 38 Novice

Clinicians self rating of comfort with researching a clinical question to ensure an evidence-based perspective

38 Novice1 222 263 234 11 13 Expert5 2

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What is the propensity to using the evidence?

20-30 year-old clinicians are: (as compared to > 50 YO)

– ~ 20x more likely to have learned the foundations of EBP in their entry level professional programin their entry-level professional program

– ~ 10-11x more likely to be familiar with on-line databases and trained in search strategies

– ~ 22x more likely to have had formal training in critical appraisal

– ~3-4x more likely to be confident in search and analysis skills


What is the biggest barrier to EBP?


Not just in the U.S.

Biggest barriers to implementation of EBP– Time required to stay current– Access to the evidenceccess o e e de ce– Lack skills to find and understand the evidence

70% of clinician respondents read the research literature at least monthly

10, 15, 25%, respectively, searched PEDro, Cochrane and Medline or Cinahl databases frequently

Iles, et al, Physiother Res Int, 2006

Here’s one final problem with EBP

Evidence is of no value if it is not found, consumed, integrated, and utilized in the assessment and treatment of o r patientstreatment of our patients

It has been estimated that it takes 15 years for empirical data to permeate and become common general practice

Possible Solution

Therapists are willing to integrate new information and change clinical practice if information is synthesized and presented to them –p ese ted to t e

– Journal Clubs with CATs

– Study reported familiar problems with integrating evidence

Lack of time

Difficulty accessing material

Inadequate research in specific areas

Fruth SJ, et al, Physiother Theory Pract, 2010

Is it possible to promote EBP?

5 Pediatric PTs provided didactic training to identify and implement EBP

Able to implement some (but not all) strategies and modest Able to implement some (but not all) strategies and modest (self‐reported) improvements in EBP behaviors and demonstrate a positive attitude towards EBP

Reported barriers were lack of time, other influences on clinical decision‐making, and lack of incentive

Schreiber J, et al, Phys Ther, 2009

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It’s time to make a change …

We’re making progress on understanding what EBP is – but that’s not enough …

We need to start making sure our behavior reflects it

Let’s not let evidence‐based practice be an oxymoron in our profession

True education occurs when …

the recipient finishes an article (or course of study) with an inquisitive perspective and goes back to the clinic with the questions ….clinic with the questions …. … how will I implement the changes suggested

how will I evaluate it’s value

a renewed commitment to consulting the evidence to guide their care

Change is good …

you go first!Being old experienced means you have invested a lot of time and effort in perfecting your logic and rationale on interventions that have now been proven wrong

How to Use Evidence

Use the evidence like a lamp post

– for illumination – not for support

Use the evidence to not only support your

paradigm

– but to challenge it

To effectively apply evidence in practice a clinician must:

Identify gaps in your knowledge Formulate clinically relevant questions (PICO) Conduct an efficient literature search

A l th l f id (i l di Apply the rules of evidence (including a hierarchy of evidence) to determine the validity of studies

Apply the literature findings appropriately to the patient’s problem(s)

Appreciate how the patient’s values affect the balance between potential advantages and disadvantages of the available management options, and then appropriately involve the patient in the decision.

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10 general areas where clinical questions arise

1. Clinical Findings2. Etiology (causes)

3 Clinical Manifestations

7. Therapeutic Interventions (worth cost and effort?)

8. Prevention 3. Clinical Manifestations

of the injury/disease4. Differential Diagnosis5. Diagnostic Tests6. Prognosis

(clinical course and complications)

(modify risk factors)

9. Experience and Meaning (how patients experience treatment and effect on therapy)

10.Self-improvement (better, faster, smarter, etc)

Deciding Which Question is the Most Important to Ask

Which question is the most important to the patient’s well being?

Which question is most feasible to Which question is most feasible to answer within your time constraints

Which question will you most likely encounter over and over in your practice?

Which question interests you the most?

Step 1 – Framing the Question

Framing the Questionin a Patient Specific Context

Begins by asking a good question

Deciding if we need background or g gforeground information

Framing the Question

A background indicates a need for

– General informationWhat is this?

How do you diagnose it?

How do you treat it?

– Assessed byReview Articles

Evidence-based textbooks

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A foreground question indicates a need for

Specific or complex clinical queries

d l h

Framing the Question

Patient‐centered questions involving the interpretation and consideration of risk vs. benefit for a specific diagnostic, prognostic, or intervention for a particular case

Assessed by

Pre‐assessed, critically reviewed studies from the literature as high on the evidence hierarchy as possible

Systematic Review of

RCTs

Multiple RCTs

RCTSystematic Review of

Below

Observational Cohort orObservational Cohort or Case Control Series

Case Reports

Expert Opinion

Unsystematic Clinical Observation

Another Example of Evidence Quality Hierarchy

Level of Level of EvidenceEvidence DescriptionDescription

Evidence supported by high quality randomized controlled trials

Evidenced supported by lower quality randomized controlled trials or prospective comparative studies

Evidence supported by retrospective comparative or case-controlled designed studies

Evidence obtained from case studies

Consensus - Agreement by an expert panel, in the absence of scientific evidence in the literature, based on experience and/or assumptions in the literature

CEBM’s Grading Scheme to Recommend Utilizing the Evidence in Practice

Grade Rationale

Aconclusive

Consistent evidence from level I RCT studies

Strong recommendations for or against a perspective can be conclusive made with this grade

B acceptable

Evidence consistent with level II and/or III studies

Fair level of confidence in making a recommendation or decision

Csuggestive

Conflicting evidence or evidence from level 4 studies

Weak confidence in decision making

D or Iweak

Insufficient evidence to make a decision

Orthopedic Section Practice Guidelines

GRADES OF RECOMMENDATION GRADES OF RECOMMENDATION based on:based on:

STRENGTH OF EVIDENCESTRENGTH OF EVIDENCE

A Strong Evidence(conclusive)

A preponderance evidence obtained from multiple high‐quality RCTs, prospective , or diagnostic studies(conclusive) , p p , g

B Moderate Evidence(acceptable)

A single high level RCT or multiple lesser‐quality RCTs

C Weak EvidenceA single lower quality RCT or evidence from multiple case‐controlled, retrospective, or case series studies

D Conflicting Evidence Higher quality studies that disagree on findings/conclusions.

E Theoretical/Found‐ational Evidence

A preponderance of evidence is from animal or cadaveric studies, from conceptual models, or from basic science research

F Expert Opinion Best practice based on the clinical experience of content experts

Neck Pain: Clinical Practice Guidelinesfrom the Orthopedic Section of the APTAJ Orthop Sports Phys Ther 2008; 38(9):A1-A34

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SummaryDeterminants for Grading Clinical Evidence

Study Study DesignDesign determinesgg

Level of Level of EvidenceEvidence

Strength of Strength of RecommendationRecommendation

determines

Frame the Question

as a

Patient Problem orPopulation of Patients

Who is the patient?– Disease or injury

Chief complaint– Chief complaint– Age– Gender– Race– Health status– Current Co-morbidities– Previous History

Intervention

What do you want to do for the patient?– Diagnose

Identify the source of the problem

– PrognosePredict outcome

– InterveneRecommend a product,

procedure, or treatment

Comparison

To what do you what to compare your diagnosis or intervention?– What are the alternatives?

Control

Placebo

Different Treatment

Different Pathology

Outcome

What specific result do you want to accomplish, improve, or affect in some measurable way?

A t di i– Accurate diagnosis

– Change in pain

– Change in patient’s perception of status

– Change in functional outcome measure

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PICO Acronym – Diagnostic Example

PICO ElementPICO Element TipsTips ExampleExample

Patient/Problem

Ask who is this patient? How would I describe this patient to a colleague? What is the common condition or disease you’re interested in? Balance precision with b it

58-year old recreational male tennis player

brevity. tennis player

InterventionWhat do I want to do for this patient (treat, diagnose, prognose)? What kind of pathology may be present? Be as specific as possible

Uncover likely source(s) of shoulder pain

Comparison

If not compared to a control group, what would be a likely alternative to the treatment or alternate diagnosis are you considering? (placebo, different form of therapy, medication, surgery)

Does this patient have a SLAP lesion, RC tear, or SAIS?

Outcome

What are the relevant outcomes? What do I hope to change? Is it measurable? Don’t just say “more effective – quantify how the intervention will specifically be more effective.

How will my inter-vention recommen-dation be affected by the diagnosis

PICO Acronym – Intervention Example

PICO ElementPICO Element TipsTips ExampleExample

Patient/Problem

Ask who is this patient? How would I describe this patient to a colleague? What is the common condition or disease you’re interested in? Balance precision with

58-year old recreational male tennis player with y p

brevity. p y

SAIS.

InterventionWhat do I want to do for this patient (treat, diagnose, prognose)? What kind of treatment am I considering? Be as specific as possible

Nitro-dur patch

ComparisonIf not compared to a control group, what would be a likely alternative to the treatment you’re considering? (placebo, different form of therapy, medication, surgery)

Placebo control group

Outcome

What are the relevant outcomes? What do I hope to change? Is it measurable? Don’t just say “more effective – quantify how the intervention will specifically be more effective.

Pain on a numerical pain rating scale or DASH functional outcome score

Who would like to ask a clinically relevant question in a PICO format? Why is a PICO helpful?

Focuses your question

Facilitates your search

Hones the results

http://askmedline.nlm.nih.gov/ask/pico.php

Hones the results

Makes you time efficient

Execute Search

Produces a couple of high quality articles that seem to address my PICO

Here’s the evidence I need for decision-

making

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Even easier ….

http://askmedline.nlm.nih.gov/ask/ask.php?from=tbld

Results

http://askmedline.nlm.nih.gov/ask/ask.php?from=tbld

We have our question… how can we find answers? Resources

•Database vs. Search Engine

•Database is a collection of stored articles

•Example: Medline

•Search Engine:

•Program designed to search the database

•Example: PubMed and Ovid search Medline database

Where can I find evidence?Search PubMed –www.pubmed.gov

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This database is housed with the NLM and is based on Medline (Index Medicus)

– Premier medical data base in the world

– 4600 refereed journals

– 12 million citations dating back to 1966

–– thethe FREE!!!FREE!!! internet version of Medline

Here’s what it looks like

Note the links for help, an overview, or a tutorial

PubMed On-line TutorialsNoteworthy Items

Search terms

Search limits

Search executed by clicking “go”

Search Results

limits

Brackets indicate “non-English

Page icon indicates abstract available

Check box to save or print desired articles

Boolean Search Terms

Boolean operators typed in caps can narrow the search

AND (pathology AND rehabilitation)

d h h it ti t i ll th– used when each citation contains all the search items

OR (diagnosis AND sensitivity OR specificity)

– used when each citation contains at least one of the terms

NOT (pathology NOT surgery)

– used to exclude a given category suffixes

* - TRUNCATION (tend*)

– used for variable suffixes

Using NOT will eliminate all results associated with that

key word

Rotator Cuff

NOT Surgery

http://www.ncbi.nlm.nih.gov/entrez/query.fcgiHere’s the URL address

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Example:Search Parameters using Clinical Queries

Search Terms: Subacromial Impingement Syndrome

Category: Diagnosis

Scope: narrow, specific search

Results: sorted by date of publication

most recent

Checked citations

Click on hyperlink to go to abstract

Indicates full-text reprint available

Now that you have your information how can you stay current?

Type in your search term(s) and click “Save Search”

Register for an account or fill in account or fill in your user name and password

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Check yes that you want to receive email alerts on this search topic and indicate when you’d like to receive; then click OK.

That’s it!

Review and Update your Saved Searches

Alternate Search Sites:

Results: can sort by date or relevance Another Alternate Search Site is …

http://scholar.google.com/

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ResultsOther On-line Search ServicesCumulative Index of Nursing and Allied Health Literature

Premier database for nursing and allied health

CINHAL

2800 journals containing 1,000,000 abstracts dating back to 1982

Just $20/year for unlimited on-line access or free for APTA members through Open Door portal

http://www.cinahl.com/

Systematic Review SiteCOCHRANE

Type in your search term

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http://www.cochrane.org/index0.htm

Physiotherapy Evidence DatabaseroPEDRO

http://www.pedro.org.au

Type in your Search Terms PEDro Search Results

search continued -

Scale considers the aspects of clinical trial quality: internal validity and whether thestudy contains sufficient statistical information to make it interpretable

PEDro Scale

Eligibility criteria defined (no point value)

Random allocationC l d ll ti Concealed allocation

Baseline comparable Blind Subjects – Therapists – Assessors Adequate Follow-up Intention to Treat Analysis Between Group Comparisons Point estimates of variability

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APTA

APTA “Hooked” Website

"grassroots" effort to develop a database containing current research evidence on the effectiveness of physical therapy interventionseffectiveness of physical therapy interventions

the project was motivated by concern that clinicians lacked access to the knowledge avail-able from current research, thus hindering evidence-based practice

Website’s Objectives

Allow members to search a database of article extractions relevant to the field of physical therapy to build support for evidence-based practice

Allow members to contribute extractions of the peer-reviewed literature to the database

List useful web resources and other information consistent with evidence-based practice

Disseminate clinical practice guidelines based on systematic reviews of the literature

Can search by keyword, ICD-9 code, or clinical scenario

Currently has about 5600 extractions

6300

Example Evidence in Practice Feature

No longer available –

http://www.ptjournal.org/info/eipList.cfm

gbeen replaced by “The Bottom Line” and Podcasts

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Podcasts

Updates on timely legislative and professional issues and in-depth educational presentations from national pmeetings – http://www.apta.org/podcast

Listen to audio versions of journal articles, abstracts, discussions, debates, etc.http://ptjournal.apta.org/misc/podcasts.dtl

Philadelphia

PanelOctober 2001

PRACTICE GUIDELINES

Join a section of the APTA

Orthopedic Section – Journal of Orthopedic and Sports Physical Therapy

Neurologic Section – Journal of Neurologic Physical Therapy

Sports Section - JOSPT, Journal of Sports Health, International Journal of Sports Ph i l ThPhysical Therapy

Acute Care Section – Journal of Acute Care Physical Therapy

Cardiopulmonary Section – Cardiopulmonary Physical Therapy Journal

Geriatrics Section- GeriNotes, Journal of Geriatric Physical Therapy

Oncology Section - Rehabilitation Oncology

Pediatric Section – Pediatric Physical Therapy

Section on Health Policy and Administration - HPA Journal

Aquatics Section – Journal of Aquatic Physical Therapy

Women's Health Section – Journal of Women’s Health Physical Therapy

Your Local Medical LibraryLIBRARY

My local UTSW Med

Center library link

As a CI supervising student affiliates

Do you have access to the school’s medical library or on-line resources?

If you don’t know?

ASK

“Sneak” into a LibraryCOLLEAGUES

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Using my sons’ username and password Other On-line Sources

http://highwire.stanford.edu– Stanford University Library’s access to 800 journals and

1,000,000+ free articleshtt // f di lj l http://www.freemedicaljournals.com– List of free medical journals

http://www.shef.ac.uk /scharr/ir/netting/– “Netting” the Evidence

www.freefulltext.com– Over 7000 scholarly journals

http://www.doaj.org/– Directory of Open Access journals

Post a question on a bulletin boardDISCUSSION BOARDS

Have information “pushed” to you

British Medical J l

PUSH

Journal

Here is the URL link to register

http://www.bmjupdates.mcmaster.ca/indes.asp


Ortho SuperSite

http://www.orthosupersite.com/default.asp?page=view&rid=3919and click on the icon at the bottom of the left navigation panel

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Click here to register and get email alerts –http://www.biomedcentral.com/bmcmusculoskeletdisord/alerts

BMC Musculoskeletal Disorders

One last “Push” Mechanism

http://evidenceinmotion.com/evidenceexpress.asp

Questions?? – Other Ideas

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Interpreting the Evidence

1. What were the results?

2. Are the results valid?

3. Can I apply the results to my patient and how will they influence the patient’s outcome

What were the results and do they help me decide what to do?

How large was the treatment effect?

Were all clinically important outcomes considered?

Does the benefit outweigh the potential harm and costs?

Were the results valid?

Primary Assessment– Were the subjects selected

randomly?– Were all subjects accounted

for?

Secondary Assessment– Who/What was blinded?– Were the groups similar in the

beginning?– Were the groups treated

equally?

Appraising the evidence

If evidence is limited to investigate a clinical intervention, a diagnostic test, or a clinical outcome we conclude:

– Insufficient: to few published studies

– Inconclusive: published studies are available but they

do not meet research design or analytic standards

– Silent: no studies in the literature address a

relationship or interest


When there is sufficient scientific evidence between a clinicalintervention and outcome we conclude

Supportive– Quantitative information from properly designed trials support a

significant relationship

Suggestive– Case reports or descriptive studies provide a

directional relationship but do not permit a statistical assessment of significance

Equivocal– Qualitative data has not provided a clear direction

There is insufficient information

Aggregate comparable studies disagree


Proven – Not Proven – Proven Not

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Cognizant of the patient’s expectations and your

common sense and experience

Research Designs …

on a very elementary level

Randomized Controlled Trial

Random assignment of subjects– Unbiased distribution of confounding variables

Prospective manipulation of variables

Precise measurement of physiological variables

Rigorous control of extraneous variables

Strong internal validity

Provides strong evidence of intervention efficacy

Randomized

Randomized Controlled Trial

Population

Control GroupReview Results

InterventionGroup

Review Results

Compare Results

Quasi-Experimental

Non-randomized assignment of subjects to groups (experimental and control)– Used when RCTs are impractical or unethical

– Evidence may be biased toward the experimental or treatment group

But evidence of treatment effectiveness is at least a little better than absence of evidence

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Epidemiological Designs

The study of society’s collective health– Descriptive Epidemiology

Patterns and trends

– Analytical epidemiologyEstablishing causation (etiology)

Epidemiological Research

Cohort Studies

Follow a group of people with a common experience/injury/disease over a defined period of time– Subject selection is defined by availability or

defined characteristics

Classification of Research DesignObservational (Quasi-Experimental)

Cohort Study– Prospective (cause-to-effect hypothesis)

V i bili i bj i k f– Variability in subject exposure to risk factors

– Subjects not exposed to risk factor(s) are considered the “controls”

– Large number of subjects and long duration of study is usually required Because of no randomization, difficult blinding, and

influence of confounding variables


Cohort Study cont -

– Observation to determine differences in incidence of injury in relation to exposure to risk factor(s)

– Risk Ratios Established Incidence rate for those exposed compared to

those not exposed to risk factor(s) over a defined period of time

TreatmentGroup

Review

Cohort Study

Group

Non-Treatment

comparisonReview

time Compare Groups


Case Control Study (analytical epidemiology)

– Retrospective (effect-to-cause hypothesis)

– Subjects with condition (cases) compared to similar subjects without the conditions (controls) Subjects matched on as many factors as possible

– Study the variability in past exposure to risk factor(s) Explore what made the group of individuals different

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Case-Control Study cont –

– Determination of whether cases and controls differ in terms of past exposures to risk factor(s)Example might be higher BMI

– Odds ratios (estimate of risk ratio) calculatedPrevalence rate (number of cases with condition)

compared between cases and controls

Injury Prevention/Treatment Effectiveness

Number Needed to Treat (NNT)

Numerical expression of the number of interventions necessary to prevent one adverse outcomeadverse outcome– Calculated based on the absolute risk ratio (ARR)

(incidence rate for control group minus the incidence rate for the intervention group)

– NNT = 1/AAR

Outcomes Research

Somewhat similar to a prospective cohort study in which patients treated at a facility are evaluated based on their outcomeevaluated based on their outcome

Can also be conducted as a true experimental study if random assignment of subjects to different treatment protocols

Classification of Research DesignObservational

Case Series– Information on a series of patient have the

same injury or illnessNo comparison or control group

Case Report– Information on a single subject

Classification of Research DesignSynthesis of Research Evidence

Systematic Review

– Criteria for inclusion of studies established prospectivelyprospectively

– Objective quality rating of evidence relevant to a specific clinical question

– May or may not include a meta-analysis of findings for multiple studies (effect sizes) Meta-analysis is a quantitative comparison of multiple

studies that have addressed the same clinical question with different method

Clinical Prediction/Decision Rules

A decision-making rule for clinicians that include 3 or more variables from– History

– Physical Exam

– Special Tests

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CPRs used for– Diagnosis of a condition

Clinical guideline in lieu of a gold standard

– Prognosis for the recovery of function Estimation of likelihood for full recovery under specific

conditions in a defined time frame

– Likely response to a particular intervention Patient characteristics linked to the choice of

treatment


CPRs are derived from systematic clinical observations

CPRs are validated by evaluating the sensitivity, specificity, and LRs of specific observations

CPRs are useful in guiding decision-making rationale


3 Stages of Maturation– Development (identification of predictors)

– Validation (assessment of accuracy)

– Impact Analysis (utilization)

Diagnostic Accuracy

Sensitivity (SNOUT)– Rule out conditions

Specificity (SPIN)– Rule in conditions

Likelihood Ratios– Shifts in probability

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