Critical AppraisalJamalludin Ab Rahman MD MPH

Department of Community Medicine

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Evidence Based Medicine“Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.”

“Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough.”

“External clinical evidence can inform, but can never replace, individual clinical expertise…”

Sackett, D. L., Rosenberg, W. M. C., Gray, J. A. M., Haynes, R. B., & Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn't (Vol. 312).

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The origin of EBM 1975, Dr David L Sackett discovered that the

factor that determine the prescription for hypertension is the graduating years of the doctors.

1990, Dr Gordon Guyatt coined the term Evidence Based Medicine for a new Internal Medicine residency programme known as “Scientific Medicine”

Kowalski, E., & Chung, K. C. (2013). The outcomes movement and evidence-based medicine in plastic surgery. Clin Plast Surg, 40(2), 241-247. doi: 10.1016/j.cps.2012.10.001

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What is EBM

Personal (maybe obsolete) own

experience

External (and current)

evidences

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Why we read clinical papers?

Sackett, D. (1981). How to read clinical journals. 1. Why to read them and how to start reading them critically. Canadian Medical Association Journal, 124(5), 555-558.

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How to critically read the journal?

Sackett, D. (1981). How to read clinical journals. 1. Why to read them and how to start reading them critically. Canadian Medical Association Journal, 124(5), 555-558.

First critical step is to know what information you are looking for in the first place?

1. Diagnostic teste.g. Using central blood pressure (pulse wave analysis) to measure risk of CAD, compared to peripheral blood pressure.

2. Clinical course & prognosise.g. 5-years survival of cancer patients following an operation procedure.

3. Aetiology & causatione.g. Talcum causing cancer.

4. Therapeutice.g. New drug is better than the old one.

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Diagnostic Evaluate new diagnostic test Compare to GOLD standard

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8How to read clinical journals: II. To learn about a diagnostic test. (1981). Canadian Medical Association Journal, 124(6), 703-710.

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Prognosis Clinical course of a disease – e.g. Recurrence rate,

3-year survival, reinfection etc.

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10How to read clinical journals: III. To learn the clinical course and prognosis of disease. (1981). Can Med Assoc J, 124(7), 869-872.

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Causation About one causing the other e.g. smoking causing

lung cancer Hierarchy of evidence

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Hierarchy of evidence

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How to read clinical journals: IV. To determine etiology or causation. (1981). Can Med Assoc J, 124(8), 985-990.

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Therapy How useful or harmful of a therapy e.g. prescribe

high dose vitamin C for cancer patient; low dose aspirin for all hypertensive patients

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15How to read clinical journals: V: To distinguish useful from useless or even harmful therapy. (1981). Can Med Assoc J, 124(9), 1156-1162.

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Appraisal Format1. Credibility of the journal & authors

2. Title – Clear & informative (explained well about the paper)

3. Summarise the study – With your own words, summarise the study

4. Keywords - Relevant

5. Abstract – How it was done? Structured or non-structured. How the study was summarised? Do you feel the information provided adequate?

6. Introduction – Study justified (rationale); objectives clearly stated

7. Methodology – Design, Sampling method, Sample size, Data definition, Data collection, Statistical analysis, Ethical issues

8. Results – Answers the objectives, Consistent, Clear illustrations or tables

9. Discussion – Answers the objectives, Discuss the strength & weakness of the study

10. Conclusion of the appraisal

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Don’t forget to tell about the study Don’t just write all about your comments Must include what is the study is all about

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EBM is a guide …and will always be just a guide Horses for courses Cross sectional studies still have important place

in research, esp. evidence based policy

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Main references Fowkes, F. G., & Fulton, P. M. (1991). Critical appraisal of published research:

introductory guidelines (Vol. 302). How to read clinical journals: II. To learn about a diagnostic test. (1981). Canadian

Medical Association Journal, 124(6), 703-710. How to read clinical journals: III. To learn the clinical course and prognosis of disease.

(1981). Can Med Assoc J, 124(7), 869-872. How to read clinical journals: IV. To determine etiology or causation. (1981). Can Med

Assoc J, 124(8), 985-990. How to read clinical journals: V: To distinguish useful from useless or even harmful

therapy. (1981). Can Med Assoc J, 124(9), 1156-1162. Greenhalgh, T. (1997). How to read a paper. Getting your bearings (deciding what the

paper is about). Bmj, 315(7102), 243-246. Sackett, D. (1981). How to read clinical journals. 1. Why to read them and how to start

reading them critically. Canadian Medical Association Journal, 124(5), 555-558.