Understanding evidence in Neurology Pemahaman Evidence di Neurologi
. J.Eko Wahono R SMF Neurologi RSUD Dr Soetomo /FK Unair .Surabaya
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Pendahuluan • 1970-an,Dr David Sackett, McMaster University Kanada Pada awalnya • penekanannya adalah pada penilaian kritis dari jurnal
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Pendahuluan .. • Di awal 1990-an, p’baharuan panduan. • Penekanan – kegunaan informasi dlm praktek klinis.
• Sumber informasi telah tersedia sangat besar lewat Internet ,
– panduan untuk dokter dalam mencari literatur yg relevan
Prof Gordon Guyatt
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Kedokteran Berbasis Bukti EBM EBM berarti • M’ggunakan bukti terbaik saat ini dlm pengambilan keputusan masalah kedokteran • bersama-sama dengan keahlian dari para pengambil keputusan dan
• harapan dan nilai-nilai dari pasien 4
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What is evidence? Evidence dlm praktek klinis adalah bukti dari: • observasi yg dilakukan dgn tujuan tertentu. • Observasi dari – penelitian klinis atau – praktek klinis atau – penelitian hewan,
• semua dianggap bukti, – tidak sama validitasnya atau – relevan utk pengambilan keputusan klinis
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Level of Evidence
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Pengertian EBM (1-2-3-4) EBM memiliki • 1 tujuan, • meningkatkan kualitas perawatan klinis
• 2 prinsip dasar, • hirarki bukti dan • insufisiensi bukti saja dalam pengambilan keputusan;
• 3 komponen • bukti, keahlian dan harapan pasien
• 4 langkah • • • •
bertanya, memperoleh, menilai dan menerapkan . (AAN, 2011) 9
Prinsip EBM:.
• Evidence • Expertise • Expectations
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Peran Keahlian Pria 28 th dirawat di RPI dgn kelumpuhan yg mulai dari bawah keatas dan gangguan pernapasan Residen m’buat Dx (GBS) Cari evidence terapi
Konsultan datang, • pernah digigit anjing 3 bln lalu • imunisasi parsial • kecurigaan rabies
RABIES 11
Patient’s Expectations
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Patient’s Expectations Expertise : ALS
Evidence : Riluzole Mahal & Resiko tinggi
Outcome
Expectations: Anggap sepadan/tidak
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MENGAPA DILAKUKAN PENDEKATAN BERBASIS BUKTI ? 14
A.Dasar pemikiran fisiologis • stroke iskemik umumnya ok oklusi dari arteri serebri media (MCA). • hubungkan cabang karotis eksternal -- ke cabang MCA diluar oklusi. • Operasi -- (EC-IC) bypass.
ribuan operasi bypass EC-IC dilakukan di dunia,
Studi yg disponsori oleh NIH (USA) • bandingkan ini dgn perawatan medis • hasilnya • operasi ini tidak efektif • tunda pemulihan. (Haynes et al., 1987) 15
B.Rekomendasi para pakar Rekomendasi pakar tanpa referensi dan evaluasi bukti yang memadai bisa salah. Terapi eklampsia. • survei di Inggris 1992 hanya 2% dari Obstetri yg pakai magnesium sulfat utk kendalikan kejang • Obat disukai adalah diazepam
Bukti dari uji klinis : • magnesium sulfat lebih efektif • menurunkan kematian ibu di eklampsia. (Fauveau and De Bernis, 2006).
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C. Buku teks dan pengulas
Despite its now minimal presence in AMI treatment in the UK and the United States, • streptokinase continues to play a major role at a global level. It is used as thrombolysis for acute MI in about half of countries worldwide because it is affordable, • explains Sleight, adding: “In countries where patients do not have rapid access to catheterisation, streptokinase is still important.”
Jenny Bryan is a medical writer based in London. 17
D. Klaim Produsen Informasi produk Obat … valid ?
Promosi HRT utk menopause
Mulai TX … ?
Uji klinis skala besar .. jelek
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5 steps in EBM
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Clinical Question
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V.I.A ▪V
:
Valid
▪I
:
Important
▪A
:
Applicable
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Steps in critical appraisal of primary research - RAMMBO • Recruitment : – Were the subjects representative of the target pop ?
• Allocation or adjustment – Was the tx allocation concealed before randomisation and were the groups comparable at the start of the trial
• Maintenance : – Was the comparable status of the study groups maintained through equal management and adequate follow up ?
• Measurement – Were the outcomes measured with
– Blinded subjects and assessors, and/or – Objective outcomes ? 22
Stucture of a comparative health care research study Study question
Aim
Study methods
Critical appraisal
P
Fair recruitment Subject representative of the target pop
Large enaugh sample + randomly
R
I
Fair allocation
Randomly allocated Adjust confounding (statitical adjustment/matching)
A
C
Fair maintenance
Manage grup equally Follow up all subjects
M
O
Fair measurement Valid & unbiased outcome measure
Measure outcome Blinded Objective measure
M B o
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Important …?
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Table 5.3. Measure of effect size
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Clinical importance vs. statistical significance Cholesterol level, mg/dl Standard treatment
300 mg/dl n=10000
R
n=10000 New 300 treatment mg/dl
t= Soedigdo
df = 9998
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Clinical 197
p = 0.00002 Statistical
Clinical importance vs. statistical significance Cured
Died
Standard Rx
0
10 (100%)
New Rx
3
7 (70%)
Absolute risk reduction = 30%
Clinical
Fischer exact test: p = 0.211
Statistical
NNT Number Needed to Treat •
The inverse of the ARR = (1/ARR) is a whole number and has the useful property of telling us
▪ the number of patients that we need to treat (NNT) ▪ with the experimental therapy for ▪ the duration of the trial in order to ▪ prevent one additional bad outcome.
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Outcome measures for binary outcomes Measure Meaning Relative risk RR – Risk of outcome in the Tx group/risk in the control group
how many times more likely event in the tx group relative to control group
RR = 1 – no diff between 2 groups
RR < 1 – the tx reduces the risk of event RR > 1 – the Tx increass the risk of the event
Example RR = 0.1/0.15 = 0.67 RR < 1 The Tx – decrease the risk of death
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Outcome measures for binary outcomes RRR Measure
Meaning
Example
RRR ARR/risk of event in the control group
RRR Reduction in the rate of event in the Tx group relative to control group
RRR = ARR / Risk of event control group
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Outcome measures for binary outcomes Measure
Meaning
Example
ARR Risk of event in the control group – risk event in the tx group
ARR = 0 – no diff ARR + the Tx is beneficial ARR - harmfull
ARR = 0.15 – 0.10 = 0.05 (5%) The absolute benefit of Tx is a 5% reduction in the death rate
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APPLICABLE …?
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ARE THE VALID, IMPORTANT RESULTS OF THIS INDIVIDUAL STUDY APPLICABLE TO OUR PATIENT?
• If the evidence valid and important,
• To apply evidence, integrate the evidence with our
consider
▪ clinical experience and ▪
apply it !! to our own patient.
▪
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expertise, pt’s values and preferences. The guides for doing this are in Table 5.5.
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Keterbatasan EBN (Prasad, 2006) • Terbatasnya aplikabilitas bukti untuk pasien perorangan • Kurangnya bukti yang konsisten dan koheren: • Berpotensi untuk membatasi kreativitas dan inovasi • Membutuhkan waktu dari dokter • Terbatasnya ketersediaan sumber informasi EBN • Perlu belajar konsep-konsep baru: (metodologis dan statistik) • peristilahan yang membingungkan 34
Kesalahpahaman tentang EBN (Caplan, 2001, Prasad, 2006)
• Pasien harus menunggu sementara dokternya mencari dan menilai bukti • Keahlian klinis diabaikan di dalam EBN • Hanya uji coba atau meta-analisis yang dilakukan secara acak akan dihitung sebagai "bukti": • EBN adalah sebuah metode bagi penelitian medis 35
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