Introduction to Evidence-Based Medicine (EBM) and Public Health (EBPH)

1. BÀI 1. DẪN NHẬP Y HOC ( EBM) / Y TẾ CÔNG CỘNG ( EBPH) DỰA VÀO CHỨNG CỨ GS TS BS LÊ HOÀNG NINH

2. Nội dung cốtlõi • Tại sao y hoc chứng cứ là quan trọng • Y học chứng cứ là gì ? • Phân biệt foreground vs. background questions • Đặt câu hỏi dạng PICO • Tìm nguồn tư liệu • Giá trị của một bào báo khoa học y học / sức khoẻ • Đánh giá các dạng bài báo : can thiệp điều trị / dự phòng; chẩn đoán/ sàng lọc; nguyên nhân…

3. Tạisao EBM làquantrọng? • MEDLINE • 400,000 new entries added each year • To keep up-to-date • Need to read 6,000 articles each day

4. Tạisao EBM làquantrọng? • sự chậm trễ “ từ lúc biết cho tới lúc áp dụng” • 13 years for thrombolytic therapy • 10 years for corticosteroids for acceleration of fetal lung maturity • (Antman EM, JAMA, 1992)

5. Traditional Approaches • Self-reported reading time per week. (University setting) • Medical students 60 min. • Interns none • Senior residents 10 min. • Fellows 45 min. • Attendings graduating • Post 1975 60 min. • Pre 1975 30 min.

6. There is simply no way we can keep up to date in medicine using traditional approaches!

7. Nội dung cốtlõi • Why is EBM important? • What is EBM? • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

8. Research Evidence Decision Making Patient Preference Clinical Expertise

9. Qui trình y họcchứngcứ / y tếcôngcộng Patients Ask Questions Appraise Searching

10. Validity Results Applicability

11. Nội dung cốtlõi • Why is EBM important? • What is EBM • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

12. What’s the difference between foreground and backgroundquestions?

13. Asking the Precise Question • Background questions • Basic aspect of a disease • Pathophysiology • Etiology • Basic treatment • Who, what, when, how • Foreground questions • Specific knowledge • Have 4 parts: • Patient/problem • Intervention • Comparison intervention • Clinical outcomes

14. Background or Foreground? • What is asthma? • Is prednisone helpful in asthma? • What are the newest medication for asthma? • Does atrovent used acutely make you feel better?

15. Background or Foreground? • What is asthma? (B) • What are the newest medication for asthma? (B) • Does atrovent used acutely make you feel better? (F) • Is prednisone helpful in asthma? (F or B) • Foreground if compare to other drugs • Background if interested in how it works

16. Nội dung cốtlõi • Why is EBM important? • What is EBM • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

17. Structure of a Well-built Question • Patient or population • Be specific to capture the group you want • Ex: Children w/ asthma • Intervention • Be specific • Comparison group (if any) • Compare to standard therapy or test • Outcome • Be precise • What are the outcome of interest

18. Formulating the Clinical Question PICO

19. Can You Identify PICO? • In children under 6 months, how does sleeping on back compared to sleeping on the stomach in terms of risk of SIDS? • In children under 6 months (P), how does sleeping on back (I) compared to sleeping on the stomach (C) in terms of risk of SIDS (O)?

20. Can You Form a PICO Question? Clinical scenario: 5 yo with moderate persistent asthma now in severe acute asthma exacerbation. Intern gave 2 albuterol and orapred with minimal improvement. Intern asks why how good is atrovent?

21. Searchable PICO Question P: Population I: Intervention/diagnostic test/risk factor C: Comparison O: Outcome In children with acute asthma exacerbation (P), will the addition of atrovent (I) to albuterol (C) decrease the rate of hospitalization (O)?

22. Nội dung cốtlõi • Why is EBM important? • What is EBM • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

23. Searching Superhero Best Bets

24. The Evidence Pyramid

26. Pre-appraised Resources • Cochrane • http://www.cochrane.org/cochrane/revabstr/mainindex.htm • Very high quality reviews • Mostly questions of therapy • National Guideline Clearinghouse • http://www.guideline.gov/ • Guidelines of varying levels of quality • Do broad searches • PEM database • http://researchinpem.homestead.com/homepage.html • Not pre-appraised

27. Pre-appraised Resources • Best Evidence Topics • http://www.bestbets.org • Developed in the ED of Manchester Royal Infirmary in UK • Usually EM topics • Free • Clinical Evidence (CE Concise) • http://www.clinicalevidence.com • From UK • Focus mostly on therapy • Free

28. Primary Search Engines • Pubmed • Ovid

29. What is MEDLINE? • MEDLINE is a DATABASE • MEDLINE is produced by the National Library of Medicine • MEDLINE is available free via Pubmed • MEDLINE is sold to many vendors, like Ovid, who search the DATA in MEDLINE through different search engines

30. PubMed: Clinical Queries • Pre-filtered searching • Search on questions of • Therapy • Diagnosis • Etiology • Prognosis • Or, search for Systematic Reviews Limit any of the categories to sensitivity (broad) or specificity (narrow)

38. OVID • Most librarians favor this search engine • Allow you to tailor your search

40. Nội dung cốtlõi • Why is EBM important? • What is EBM • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

41. Appraise (Validity) • http://www.cebm.utoronto.ca/teach/materials/dx.htm • http://www.cebm.utoronto.ca/teach/materials/therapy.htm

42. Validity of Therapy Articles • Randomized? • Blinded? • Were the subjects similar at the start of the trial? • Were all subjects treated the same except for the treatment of interest? • Were all patients accounted for at the end of the trial?

43. Validity: 1. Were the Subjects Randomized? “Methods” section

44. Validity: 2. Were They Blinded? “Methods” section

45. Validity: 3. Were the Subjects Similar at the Start of the Trial? “Results” section

46. Validity: 4. Were All Subjects Treated the Same except for the Treatment of Interest? • “Methods” section

47. Validity: 5. Were All Patients Accounted for at the End of the Trial? “Results” section

48. Validity of the Article • Was the study randomized? • Were the subjects blinded? • Were the subjects similar at the start of the trial? • Were all subjects treated the same except for the treatment of interest? • Were all patients accounted for at the end of the trial?

49. Nội dung cốtlõi • Why is EBM important? • What is EBM • Understand foreground vs. background questions • Formulate PICO questions • Find resources, do searches • Validity of an article • Appraise “Therapy” articles • Appraise “Diagnostic” articles

50. Step 4: Appraise “Therapy” Study • Therapy study • Number Needed to Treat (NNT) to prevent an adverse outcome • Mathematically • NNT= 1/ARR (absolute risk reduction) • ARR = Risk of adverse outcome in the control group (CER) – those in the experimental group (EER) • ARR* = CER** – EER*** • *ARR: Absolute risk reduction • **CER: control event rate • ***EER: experimental event rate