Appraising Evidence into our Practice

Objectives Deciding the research result into practice in specific context Interpreting/calculating Number Needed to Treat (NTT) Interpreting pre and post test Interpreting/calculating Number Needed to Harm (NHH)

Introduction Health related research takes places over the world Specific situation or patient where the study was taking place probably different with the current situation Sample population characteristic ? Standard of services ?

Assessing Applicability Are the Findings Applicable in My setting? What do The result Mean for my Patient? Is the quality of the Study good enough to use the result?

Factors to consider when assessing applicability Characteristic of the participant: co morbidity, severity, gender Characteristic of the participant: co morbidity, severity, gender Feasibility to introduce the intervention: specialist unit, generalist unit, management system? Feasibility to introduce the intervention: specialist unit, generalist unit, management system? Think about cost and benefit Think about cost and benefit Patients preference. Forcing patient to accept the intervention is unethical. Patients preference. Forcing patient to accept the intervention is unethical.

Meaning the Result Study Quality of the study design is the most important thing Quality of the study design is the most important thing Avoiding the result by chance Avoiding the result by chance ℘ < (probability by chance < 1 in 1000) ℘ < (probability by chance < 1 in 1000) Number needed to treat (NNT) is useful for interpreting the effectiveness Number needed to treat (NNT) is useful for interpreting the effectiveness

Example Patient: Sandra, 11 y.o with 4 admission within 6 month EBP Question: Does a structured nurse-lead discharge package result reduce level of readmission in children with acute asthma? Evidence: Wisendly, C (1999) Stucture discharge procedure for childern with acute asthma: an RCT study. Journal of children nursing 4 (40):77

Example Result Report: Reduction in admission at 6 month. Control group: 30 of 80 Intervention group: 12 of 80 Make 2 x 2 Table

Outcome: Readmission within 6 month Total Group Study PresentAbsent Intervention 12 ab 68a + b = 80 Control30 c d 50c + d = 80 Total 42 (a + c) (b + d) 118a + b+ c + d = 160

Calculating NNT StepMeasureFormulaExample 1234 Experiment even rate (EER) Control even rate (CER) Absolute risk reducation (ARR) NNT a/a + b c/c + d CER – EER 100/AAR 12/ = 15% 30/ = 37% 37-15=22% 100/22 = 5 (rounded up)

The Mean NNT = 5 means, 5 children need to received structured discharge package to prevent one extra child from being readmitted if they had received standard care.

Number Needed to Harm Patient: florence, 33, using oral contraception, smoke cigarettes/day. Clinical question: are women who smoke with oral contraception at higher risk of myocardial infarction comparing with non smoker? Evidence: Matt, J (1999)Risk of myocardial infarction and angina in users of oral contraception. Update analysis of Cohort study. British journal of obstetric 3(90)pp1-5

Number Needed to Harm Result: In heavy smokers there is a fourfold in the risk of myocardial infarction if the pill of oral contraception is taken. 0,24 per 1000 women/year in heavy smoker who never used oral contraception to 1,18 per 1000 women at risk in current users of oral contraception. Heavy smoker relative risk is 4.0 for ex user of oral contraceptive pill, 4.2 for ever-user and 4.9 for current user

Calculating NNH Adverse Outcome: Myocardial infacrtion Total Group Study PresentAbsent Yes: heavy smoker + oral cont aba / (a+ b) = rate in yes group No: Non smoker + No oral cont c dc / (c + d = Rate in no grup

Calculation MeasureFormulaExample Relative risk (RR) Absolute risk increase (ARI) Number needed to harm (NNH) a/(a+b)c/(c+d)a/(a+b)-c/(c+d)1/ARI 1.18/0.24 = =0.94 per 1000 person 1/ =1063

The Mean The number of women who smoke heavily that would have to take oral contraception for 1 year to cause one extra myocardial infarction. In this study, a total 1063 heavy smoker would need to take oral contraception for 1 year for 1 extra women to experience a myocardial infarction.

Conclusion Are the Findings Applicable in My setting? What do The result Mean for my Patient? Is the quality of the Study good enough to use the result?

Conclusion We know the patient We can compare the evidence with the local situation Cost and benefit should be consider However, there are no perfect study as every design has they own limitation

Developing Guideline

Level of Evidence & Recomendation