critical appraisal to treatment

8/11/2019 Critical Appraisal to Treatment

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Putu Moda Arsana

FKUB, Malang,2012

CRITICAL APPRAISAL TOTREATMENT STUDY


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BASIC CONCEPT

Applicable

Important

Validity


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VALIDITY

Was the assignment of patients to treatments randomized?randomized--

Was follow-up of patients sufficiently long and complete?follow up--

Was the randomization list concealed?concealed-- Were all patients analyzed in the groups to which they were randomized?

Were patients, clinicians, and study personnel kept blind to treatment?

Were the groups treated equally, apart from the experimental treatment?

Were the groups similar at the start of the trial apart from the experimentaltherapy?


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IMPORTANT

What is the magnitude of the treatment

effect?

How precise is the estimate of the

treatment effect?


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Applicability:Can you apply this valid, important evidence about

therapy in caring for your patient?

Do these results apply to our patient?

Is our patient so different from those in thestudy that its results cannot apply?

Is the treatment feasible in our setting?

What are our patients potential benefits and harms from the therapy?

Method I: f Risk of the outcome in our patient,relative to patients in the trial.Expressed as a decimal:______NNT/f=______/______=______(NNT for patients like ours)

Method II: 1/(PEERRRR) Our patients expected event rate if theyreceived the control treatment (PEER)=______1/(PEERRRR)=1/________=______(NNT for patients like ours)

Are our patients values and preferences satisfied by the regimen and its consequences?

Do we and our patient have a clear assessmentof their values and preferences?

Are they met by this regimen and its

consequences?


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IMPORTANT

Occurrence of diabeticneuropathy at 5 years among

insulin-dependent diabetics in

the DCCT trial

Relative riskreduction

(RRR)

Absolute riskreduction

(ARR)

Numberneeded to treat

(NNT)

Usual insulin

regimen controlevent rate

(CER)

Intensive insulin

regimenexperimental

event rate (EER)

CEREER

CER

CEREER 1/ARR

9.6% 2.8% 9.6%2.8%

9.6%

=71%

9.6%2.8%

=6.8%

1/6.8%

=15 patients

Result in population 95% CI 4.4% to 9.2% 11 to 23


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RUMUS CI 95% ON ARR

CER 1 CER EER 1 EER 1.96

number of control patients number of experimental patients

0.96 0.904 0.028 0.9721.96

730 711

2.4%

Jadi ARR pada populasi = 6.8% 2.4% = 4.4% - 9.2%.

NNT pada populasi = 1 : ARR populasi = 11 23 pasien


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A 65-year-old man is seen in our office after being

discharged from hospital 2 weeks previously. During thisadmission he suffered a transient ischemic attack (TIA),

and being diagnosed with carotid stenosis. His hospital

stay was uncomplicated and his discharged medications

included metoprolol50 mg BID for hypertension andaspirin 81 mg daily. Today, he brought us an article from

the internet describing the benefits of statinsfor stroke

prevention and he wonders what this medication is and if

he should take it. Our note from his last visit showed that

his TC was 5.0 mmol/L, HDL-C was 2.0 mmol/L, and

LDL-C was 2.0 mmol/L.

His examination was unremarkable

(Strauss SE, et.al.Therapy in: Evidence-Based Medicine, 2005)

CLINICAL SCENARIO (modif ied)


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STEPS

Ask a foreground question

Acquire some articles

Appraise the evidence

Apply the findings

Assess your performance


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GOOD CLINICAL TRIAL

VALID

IMPORTANT APPLICABLE


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ARE THE STUDY VALID?

1. Was the assignment of Pxrandomized? Yes

2. Was follow-up sufficiently long & complete? Yes

3. Was all Pxanalyzed in groups?4. Were Px& Dr kept blind to Rx?

5. Were groups treated equally?

6. Were groups similar at start of study?


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Loss of follow up :

15+10=25

25/4731= 0.53%

Intention to treat analysis


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Clinical trials:a, b, c are accounted as failure of Exp arm


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WHAT IS MEANT BY INTENTION TO TREATANALYSIS? SURVEY OF PUBLISHEDRANDOMIZED CONTROLLED TRIALS

(Hollis S, Campbell F. BMJ 1999; 319: 670 -4)


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1.Was the assignment of Pxrandomized? Yes


3. Was all Px analyzed in groups? Yes4. Were Px& Dr kept blind to Rx?

5.Were groups treated equally?



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3. Was all Pxanalyzed in groups? Yes

4. Were Px& Dr kept blind to Rx? Yes

5.Were groups treated equally?



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Are the study valid?



3. Was all Pxanalyzed in groups? Yes

4. Were Px& Dr kept blind to Rx? Yes

5.Were groups treated equally? Yes



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Is SPARCL Study valid?

Yes this is valid !


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ARE THE VALID RESULTS OFTHE STUDY IMPORTANT?

1.What is the magnitude of R/ effect?

2.How precise is this estimate of R/ effect?


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IMPORTANCE

1. MAGNITUDE OF THE TREATMENT P value

Relative Risk Reduction (RRR)

Relative Risk Increase (RRR)

Absolute Risk Reduction (ARR) Absolute Risk Increase (ARI)

Number Needed to Treat (NNT)

Number Needed to Harm (NNH)

2. HOW PRECISE IS THE TREAMENT EFFECT?

Construct Confidence Interval (CI)


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NNT = number needed to treat= number of patients should be treated to

avoid 1 bad outcome avoid outcome= number of patients should be treated to

have 1 additional outcome have outcome

NNH = number needed to harm= number needed to harm one more patient

from the therapy


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ABSOLUTE RISK REDUCTION PRIMARYOUTCOME ON FATAL OR NON FATAL STROKE

ABSOLUTE RISK REDUCTION (ARR) : 13.1-11.2 = 1.9

NNT = 1/ARR X 100% = 100/1.9 ~ 52.6 ~ 53


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ABSOLUTE RISK INCREASE (ARI) ONHEMORRHAGIC STROKE (HS)

Atorvaevent rate (HS) : 55/2365 X 100%= 2.32%

Placebo event rate (HS) : 33/2366 X 100%= 1.4%

ARI HS : 2.32%-1.4% = 0.92 %

Number Needed to Harm (NNH) :

1/ARI X 100% = 1/0.92 x 100%= 108

Note: kejadianHS padaatorvaada55 pasiendari2365 pasien group

atorvasedangkanpadaplasebosebanyak33 dari2366 pasien group

plasebo---l hal554

LHH (LIKELIHOOD OF BEING HELP VERSUS HARMED)


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LHH (LIKELIHOOD OF BEING HELP VERSUS HARMED)

IN REGARDS HEMORRHAGIC STROKE VSPRIMARY

OUTCOME (NON FATAL OR FATAL STROKE)

LHH = (1/NNT) vs (1/NNH)

1/53 vs 1/108

2.03 times

ARTINYA: kecenderungan untuk memberikan atorvastatin

benefitnya dua kali lebih baik dibandingkan dengan hanya

memberikan plasebo


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EBM Study Group

Is the results of SPARCL study

important?

Yes this is important!


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HOW TO SOLVE CONFOUNDING FACTORS?


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IS THERE ANY HIGHER

EVIDENCES?


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