The level of evidence utilized to answer general practitioners’ questions
Karen Davies
Evidence Based Medicine
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Clinical Expertise
Patient Preferences
Research Evidence
Haynes et al., 1996
EBM - Levels of Evidence
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Meta analysisSystematic Reviews
Randomized Controlled Clinical Trials
Cohort StudiesCase Control StudiesCase Series / Reports
Anecdotal
Level One
Level Two
Research Objectives
• To determine the highest level of evidence per question
• To determine the number of questions not answered due to a lack of evidence
• To determine the number of times a guideline was used to answer a question
• To determine the type of websites used to answer questions
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EBM Levels Used in This Study
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(Meta analysis)Systematic Reviews
Randomized Controlled Clinical Trials
Cohort StudiesCase Control StudiesCase Series / Reports
Anecdotal
Guidelines
Websites
Level One
Level Two
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Methodology
• Two national primary care answering services - ATTRACT and NLH Primary Care Answering Service
• Clinical questions
• Identified the type of evidence used to answer the question
• Data was collected for four months, from 1st March to 30th June 2008
•
Highest Level of Evidence
• 11 of the 57 ATTRACT questions answered by level 1 or 2 in the evidence hierarchy – 19%
• 74 of 724 Primary Care Answering Service questions answered by level 1 / 2 evidence – 10%
• Average 11%
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Questions Not Answered
• 2 out of 57 ATTRACT questions – 3.5%
• 125 out of 724 NLH Primary Care Answering Service questions – 17%
• Average 16%
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Guidelines Used
• 24 of the 57 questions from ATTRACT - 42%
• 301 of the 724 questions from NLH Primary Care Answering Service – 42%
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Type of Websites
• 14 (18%) websites were used by ATTRACT and 116 (25%) by Primary Care Answering Service
• Not for Profit
• NHS (National Health Service)
• Average – 17%
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Evidence for the Questions
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Leve
l 1
Leve
l 2
Guid
eline
s
Web
sites
Oth
er
Not A
nswer
ed0
10
20
30
40
50
NLHATTRACT
Questions and Their Evidence I
• What evidence is there for the use of light boxes in the treatment of SAD?
• Are there any alternative /complimentary therapies recommended for IBS?
• Are there benefits from mindfulness therapy?
• What is the evidence for the use of statin in secondary prevention in the over 80's?
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Questions and Their Evidence II
• In a 36 year old, hysterectomy and not eligible for HRT, how do we manage osteoporosis risk?
• What are the potential causes of foot numbness, spreading to both legs?
• Can a tens machine be used by a patient who is 20 weeks pregnant?
• Is there any evidence of an interaction between warfarin and litozin?
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Why Is This Research Useful?
• NLH Primary Care Answering Service closed
• Useful service
• Guidelines may answer 40% of questions
• 10% of questions were answered using level 1 or 2 evidence
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