Harm, Critical Appraisal

  • View
    217

  • Download
    0

Embed Size (px)

Text of Harm, Critical Appraisal

  • 8/13/2019 Harm, Critical Appraisal

    1/15

    Critical Appraisal

    EMB Harm

    Isti Ilmiati Fujiati

    Dept. Ilmu Kedokteran Komunitas

    FK USU

  • 8/13/2019 Harm, Critical Appraisal

    2/15

    Artikel tentang Harm

    Title:

    CLOPIDOGREL Versus ASPIRIN andESOMEPRAZOLE to PREVENT

    ULCER BLEEDING

    The New England Journal of Medicine

    2005

  • 8/13/2019 Harm, Critical Appraisal

    3/15

    There has been no prospective trail to assesswhether clopidogrel is an alternative to aspirinplus a proton-pump inhibitor for patients at risk

    for ulcer.

    Hypothesis:

    Clopidogrel would not be inferior to aspirin plusesomeprazole in the prevention of recurrentulcer bleeding among the high risk patients.

  • 8/13/2019 Harm, Critical Appraisal

    4/15

    Research design:

    Randomized clinical trial (RCT): prospective,

    randomized, double-blind trial

    Ethics committee approval

    Informed consentAdjudication committeestudy end points

  • 8/13/2019 Harm, Critical Appraisal

    5/15

    Random assign:

    Clopidogrel daily + esomeprazole placebo twicedaily

    Aspirin daily + esomeprazole twice daily Follow up: 12 months

    Clinical outcome: recurrent ulcer bleeding

    Based on assumptions the sample sizecalculation would be: total sample 319,consecutive sampling

  • 8/13/2019 Harm, Critical Appraisal

    6/15

    Are the results of this harm study valid?1. Were there clearly defined groups of patients,similar in all important ways other than exposure

    to the treatment or other cause?

    Yes. Randomization would tend to make the two groupsidentical. It balances the groups for cofounders.

    o Randomization random numbers Eligible patients based on criteria:

    o Inclusion: ulcer healing, H.pylori (-), anticipated regular used use ofantiplateleto Exclusion

  • 8/13/2019 Harm, Critical Appraisal

    7/15

    2. Were treatments/exposures and clinical outcomesmeasured in the same ways in both groups (Was

    the assessment of outcomes either objective or

    blinded to exposure)?

    Yes, Treatments: seal envelopes; drugs identicalOutcomes: Endoscopy was performed in a treatment-blinded fashion to determine the ulcer.

    Are the results of this harm study valid?

  • 8/13/2019 Harm, Critical Appraisal

    8/15

    3. Was the follow-up of study patients sufficientlylong (for the outcome to occur) and complete?

    Are the results of this harm study valid?

    Yes,long up to 15% of those taking aspirin whohave a history of bleeding from ulcers hadrecurrent bleeding within one year.

    follow up12 monthcompletesample size calculation: 319 patientswith assumption 10% loss to follow-up.

    Nearly 320 patients completed follow-up.

  • 8/13/2019 Harm, Critical Appraisal

    9/15

    4. Do the results of the harm study fulfill some ofthe diagnostic test for causation?

    Are the results of this harm study valid?

    Yes,Another study reported that 12 who took clopidogrel hadulcer bleeding within one year.clopidogrel impairs the healing of gastric ulcers bysupressing the release of platelet-derived factors.

  • 8/13/2019 Harm, Critical Appraisal

    10/15

    1. What is the magnitude of the associationbetween the exposure and outcome

    Are the valid results of this harm study important?

    RR = ? NNH =?

  • 8/13/2019 Harm, Critical Appraisal

    11/15

    Importance:

    Recurrent

    Bleeding (+)Recurrent

    Bleeding (-)

    total

    clopidogrel 13 148 161

    Aspirin andesomeprazol

    1 158 159

    total 14 306 320

    RELATIVE RISK

    (RR) = A/(A+B) : C/(C+D)

    = 13/161 : 1/159

    = 0.081/0.0063

    =12.86

  • 8/13/2019 Harm, Critical Appraisal

    12/15

    NNH = 1 / { A/(A+B)} {C/(C+D)}NNH = 1/ 0.081-0.0063NNH= 1/0.0747NNH= 13.4

    We need 13 patients to be exposed to clopidogrel toproduce one additional recurrent ulcer bleeding ofgastrointestinal events.

  • 8/13/2019 Harm, Critical Appraisal

    13/15

    2. What is the precision of the estimate of theassociation between the exposure and theoutcome

    Are the valid results of this harm study important?

    RR with Confidence interval 95%: 11,49-14,19

  • 8/13/2019 Harm, Critical Appraisal

    14/15

    1. Is our patient so different from thoseincluded in the study that its results cannotapply?

    No, our patients mostly similar to the patientsin the study

    2. What is our patients risk of benefit andharm from the agent?avoiding the recurrent ulcer bleeding fromclopidogrel

    Can this valid and important evidence about harm beapplied to our patient?

  • 8/13/2019 Harm, Critical Appraisal

    15/15

    3. What are our patients preferences, concerns andexpectations from this treatment?

    no more symptoms of gastric bleeding as

    consequences of clopidogrel therapy.

    4. What alternative treatments are available?Yes,aspirin plus esomeprazole therapy or takingaspirin with enteric coated preparation.clopidogrel may given to patient with no

    history of gastric ulcers.

    Can this valid and important evidence about harm beapplied to our patient?