EVIDENCE BASED MEDICINE CRITICAL APPRAISAL THERAPY Steps of

EVIDENCE BASED MEDICINE CRITICAL APPRAISAL THERAPY

Steps of practicing EBM Assess your patient Clinical examinatio (local , abdominal …ect) then determine the CC and the nedd for EBM Ask clinical question Best diagnosis modality, treatment, prognosis, and the harm that may affect the pt. Acquire the evidence Appraise the evidence Apply the evidence to pt. care Ebm resources( ready made evidence, un ready appraised evidence) Appraise the primary research that you cant depend on it ( methodology)

Ask clinical questions Build a question with 4 main components P opulation / Situation I ntervention / Exposure C ounter intervention O utcome T imeframe

Types of questions Background questions Foreground questions

Bachground questions Where to find the answers? Mainly for students

Foreground questions Where to find the answers? Mainly for practioner

Evidence pyramide

Levels of evidence Graded according to its power 1 - systemic reviews of well conducted RCT or large RCTs. 2 -systemic reviews of well conducted observational studies or large observational studies. 3 - systemic reviews of descriptive studies or large descriptive studies. 4 - opinion of respected authorities.

Put In Mind - There is no perfect trial - Prestigious journal or authors are never a seal of guarantee of quality ( Appraise the Evidence ) - A badly conducted or biased research is hazardous to one’s practice and patient as much as a good one is useful to them.

Why we need to do Critical Appraisal

The effect of the 2500 most common used drugs

Why A systematic review (Williamson, 1986) From 4235 reachers articles published in 30 journals 9 among them BMJ, JAMA, NEJM, Lancet) only 20% met the validity criteria. (Mc. Kibbon et al. , 2004) From 60, 352 articles published in 170 journals in year 2000 Only 4132 (6. 8%) were of high quality and clinical relevant.

Question Study Therapy RCTs Harm Cohort Etiology and risk factors cohort and case control Diagnosis Cross- sectional Different research questions require different study designs. For example the best design for studies evaluating the effectiveness of an intervention or treatment is a Randomized controlled trial.

Studies are also subject to Bias, Confounders and it is important that researchers take steps to minimize this bias &confounders. For example, use of a Control group, Randomization and blinding.

Important aspects about the RCTS Randomization Bliniding Allocation concelment Intention to treat analysis

Critical appraisal is the process of systematically examining research to assess its: - Validity - Results - Relevance Before using it in decision making. The Critical Appraisal aims to help people develop the necessary skills to make sense of scientific evidence based on validity, results and relevance.

• Research involves gathering of data , collection of data and analysis of the data to produce meaningful information. • However, many of the research are not in good quality and many studies are biased and their results are untrue. • This can lead us to draw false conclusions

The triangle of Appraisal Relevance Is Is go the od ar m ticl et e ho of do lo gy Validity the pra articl ctic e e an relev d m ant y pa to m y tien t Triangle of Critical appraisal the ect s i t Wha ment eff t trea Results

Validity The degree to which the results of a study are likely to be true and free from bias. Validity depends on the methodological quality of the research

Experimental group Follow up Control group Follow up Outcome compared Randomly assigned Experimental group

Always Remember Minimize Bias by Randomization Allocation concealment Double blinding Intention to treat analysis R A D I

Results how large was the treatment effect? * EER Experimental Event Rate * CER Control Event Rate * NNT Number Needed to Treat How precise was the estimate of the treatment effect? * p: P Value * 95% C. I: 95% Confidence Interval?

Example 1 A RCT was done to evaluate a new drug claimed to prevent common cold in children. 1000 child received placebo and 1000 received the drug. During 6 months follow-up cold occurred in 200 of the kids on active treatment and 300 of the kids on placebo.

Results Tabulation 1000 child received placebo and 1000 received the drug on 6 months follow-up cold occured in 200 of the kids on active treatment and 300 on placebo Common cold No common cold GI: Drug 200 800 GII: Placebo 300 700

Event +Ve Event-Ve EXP GRP 200 800 CTL GRP 300 700 EER= 20% CER= 30% 10% ARR NNT=100/ ARR NNT= 100/10 NNT= 10

Example 2 In the Coronary Primary Prevention trial (1985); patient with high serum cholesterol level were randomized to receive either cholestyramine or an equally foul-tasting placebo and the outcome was cardiac death after 7 -10 years. In the cholestyramine group; there were 30 cardiac deaths out of 1900 participants and in the placebo group; there were 38 cardiac deaths out of 1906 participants

Result Tabulation Cholestyramine group: 30 cardiac deaths out of 1900 Placebo group: 38 cardiac deaths out of 1906 EER= 30/1900 X 100= 1. 58% CER= 38/1906 X 100= 1. 99% ARR= 0. 41% NNT= 100/ ARR 100/0. 41= 244

Relevance The degree to which the result can be applied to one’s own patients. * Different patient * Relevant outcomes not considered * Intervention can not be applied to my patient ( Availability, Cost, Harm/Benefit ratio)

Clinical Scenario It is the croup season and you have a large pediatric population in your practice. You have been taught that the use of corticosteriods for croup is controversial and should be used only as a parenteral therapy or with a nebulizer in hospitalized patients. But you wonder wether you can use oral corticosteriods for children with croup!

The PICO P Children with croup I Oral corticosteriods C Parenteral or nebulized corticosteriods O Croup score In children with croup; what is the effectiveness of oral corticosteriods compared to parenteral corticosteriods in reducing symptoms.

Steps to find Evidence 1 - Determine the domain of the question 2 - Determine the best study type to answer it 3 - Formulate the search strategy 1 - What are the key words 2 - Where to search 3 - How to search 4 - Perform the search 1 - Pre-appraised sites 2 - Primary research ( Pub. Med) 5 -Choose relevant studies for appraisal ( Largest, best methodology)

The Search P I Primary term Synonym 1 Synonym 2 ( Croup Or respiratory s Or distress) AND ( Corticosteriods Or Mesh Or ) AND C (Oral Or Or Nebulized Or Parenteral (IV, IM) )AND O Croup score Or recovery Or improvement

The Cochrane Library Clinical Evidence EB- Guidlines Pub. Med

Critical Appraisal work sheet Are the results of the study valid? Are the valid of this randomized important ? Can you apply this result on your patient?

Now you can drink your Coffee