Critically Appraised Topics 23June2014 (1) (2)

7/21/2019 Critically Appraised Topics 23June2014 (1) (2)

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CriticallyAppraised

Topics:

An OverviewMarishiel Mejia-Samonte, MD, DFM


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Evidence-Based Medicine

Systematic approach

Acquisition

Appraisal

Application


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more than 12,000 new articles, includingpapers, are added to the MEDLINEdatabase each week

'information overload

develop efficient skills in critical appraisal

Young, JM & Solomon, MJ. How to Critically Appraise an Article

Nat Clin Pract Gastroenterol Hepatol. 2009;6(2):82-91.


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focus only on the highest-quality studiesthat will guide their clinical practice

extrapolate information when necessaryfrom studies of less rigorous design if high-quality trials are unavailable

Young, JM & Solomon, MJ. How to Critically Appraise an Article

Nat Clin Pract Gastroenterol Hepatol. 2009;6(2):82-91.


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Critical Appraisal

Systematic process used to identify thestrengthsand weaknessesof a research

article in order to assess the usefulnessand validityof research findings

The rules of evidence vary with

circumstances


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Critical Appraisal

NO 'gold-standard' instrument for criticalappraisal exists

criteria used are not static evolve with improvements in

understanding of the important sources ofbias inherent in different study designsand increased awareness of the potentialinfluence of other nonmethodologicalfactors, such as conflicts of interest


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Most Important Componentsof a Critical Appraisal

Evaluation of the appropriateness of the studydesign for the research question

Careful assessment of the keymethodological features of this design

Other factors that also should be considered:

Suitability of the statistical methods used andtheir subsequent interpretation

Potential conflicts of interest Relevance of the research to one's own

practice

Young, J.M. and Solomon, M.J., 2008


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10 Basic Questions Asked

1. Is the research question relevant?

Always the first question asked

Subjective opinion

What might be crucial to some will beirrelevant to others


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2. Does it add something new?

New ideas or knowledge are usually

based on previous work Breakthrough researches are rare

Researches that make incrementaladvances are also valuable

Repeating a study can increase its validity Extending the original article to a new

population


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3. What type of research question does thestudy pose?

Components of a well-developedresearch question:

P = the group or population of patients

I/C = the studied parameter (e.g. a therapy

or clinical intervention)

O = the outcomes of interest


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10 Basic Questions Asked4. Was the Study Design Appropriate for theResearch Question?

Heirarchy of study designs


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10 Basic Questions Asked4. Was the Study Design Appropriate for theResearch Question?

However, in some circumstances, RCTs are

either not feasible or considered ethicallyinappropriate. These issues are morecommon in nonpharmaceutical trials, such asthose of surgical procedures.

When specific design is not feasible, thereasons that preclude its use will determinethe type of alternate study design that canbe used


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10 Basic Questions Asked5. Did the Study Methods Address the KeyPotential Sources of Bias?

Presence of bias means that the results of astudy have deviated from the truth

chance (e.g. a random error) = Random errordoes not influence the results in any particulardirection, but it will affect the precision of thestudy

study methods (systematic bias) = Systematic

bias has a direction and results in theoverestimation or underestimation of the'truth'.


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6. Was the Study Performed in Line with the OriginalProtocol?

Deviations affect the validity or relevance of a study

Failure to recruit the planned number of participants potentially reduces the extent to which the results of

the study can be generalized

reduces the power of the study

Changes to the inclusion and exclusion criteria Variation in the provided treatments or interventions

Changes to the employed techniques or technologies,

and changes to the duration of follow-up.


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7. Does the Study Test a Stated Hypothesis?

A hypothesis is a clear statement of what

the investigators expect the study to find Hypothesis states the research question in

a form that can be tested and refuted

Null hypothesis states that the findings of a

study are no different to those that wouldhave been expected to occur bychance.


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10 Basic Questions Asked8. Were the Statistical Analyses PerformedCorrectly?

Difficult for nonstatisticians

All quantitative research articles shouldinclude a segment within their 'Method'section that explains the tools used in thestatistical analysis and the rationale for thisapproach

Original data should be presented in such away that readers can check the statisticalaccuracy of the paper.


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9. Do the Data Justify the Conclusions?

Are conclusions reasonable on the basis of

the accumulated data

Issues to be wary of are whether the authors

generalized their findings to broader groups of

patients or contexts than was reasonable

given their study sample, and whether

statistically significant associations have been

misinterpreted to imply a cause and effect


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10 Basic Questions Asked10. Are There any Conflicts of Interest?

Researchers are in a position to decide which

studies will be conducted in their unit, whichpatients will be invited to participate in astudy and whether certain clinicaloccurrences should be reported as adverseevents

Decisions require researchers to act withintegrity and not for personal or institutionalgain


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Parts of a Critical Appraisal

Internal Validity

What are the Results?

External Validity / Applicability

Th


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Therapy

Was the assignment of patients totreatment randomised?

Were the groups similar at the start of the

trial?

Aside from the allocated treatment, weregroups treated equally?

Were all patients who entered the trial

accounted for? And were they analysedin the groups to which they wererandomised

Internal Validity

Th


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How large was thetreatment effect?

RR ARR

RRR

NNT

How precise wasthe estimate of thetreatment effect?

Will the results helpme in caring for my

patients?

Results

Therapy

ExternalValidity

Or

Applicability

Di ti


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Internal Validity

Was the diagnostic test evaluated in arepresentative spectrum of patients (likethose in whom it would be used in

practice)?Was the reference standard applied

regardless of the index test result?

Was there an independent, blind

comparison between the index test andon appropriate reference (gold)standard of diagnosis?

Diagnostics

Di ti


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Are testcharacteristics

presented? Sensitivity

Specificity

Positive Predictive

Value Negative

Predictive Value

Diagnostics

Were the methodsfor performing thetest described in

sufficient detail topermit replication?

Results ExternalValidityOr

Applicability

P i


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Internal ValidityWas the defined representative sample of

patients assembled at a common (usuallyearly) point in the course of their disease?

Was patient follow-up sufficiently long andcomplete?

Were outcome criteria either objective orapplied in a blind fashion?

If subgroups with different prognoses wereidentified, did adjustment for importantfactors take place?

Prognosis

P i


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How likely are theoutcomes over

time? How precise are

the prognosticestimates?

Prognosis

Can I apply thisvalid, importantevidence about

prognosis to mypatient?

Results ExternalValidityOr

Applicability


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Internal Validity

What question (PICO) did the systematicreview address?

Is it unlikely that important, relevant studieswere missed?

Were the criteria used to select articles forinclusion appropriate?

Were the included studies sufficiently validfor the type of question asked?

Were the results similar from study to study?

Systematic Review


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How are the resultspresented?

Will the results helpme in caring for mypatients?

Systematic Review

Results

External Validity

OrApplicability


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What do we do with theappraised articles?

discuss the published informationgathered from these appraised articles

regarding a particular subject matter

APPLY IT TO YOUR PATIENTS


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WORKSHOP1. Divide yourselves into 8 groups composed of

10 to 11 members per group (this will be yourpermanent grouping for Research 1).

2. Articles will be provided to the differentgroups.

3. Determine if the appraisal questions can beanswered or not using the abstract alone,

using full text, not at all

Therapy


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Therapy

Diagnostics


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Diagnostics

Prognosis


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Prognosis


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Systematic Review

Critically Appraised Topics 23June2014 (1) (2)

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