# Chapter 14 End Of Case Exercises

941 WordsMar 24, 20174 Pages
HADM 5132: MANAGERIAL EPIDEMIOLOGY INSTRUCTOR: Dr. Mitchell Jordon Chapter 14 end of case exercises [Page: 405 -407] Uday Sekhar Reddy Mareddy Thaddeus Wesley Question 1: a. Benefit of the treatment is Difference in the outcome for diseased patients who receive treatment compared to those who don’t take treatment. Benefit of treatment = 6% b. Harm of treatment is the difference in the outcome for patients without the disease who receive treatment compared to those who do not. Harm of treatment = 2% c. Treatment Threshold = Harm/ (harm + Benefit)…show more content…
Treatment Threshold = 0.05/ (0.05+ 0.20) = 0.2 or 20 % If prevalence of Acute Myocardial Infarction is greater than 20% indicates that bypass surgery procedure will outweigh the risks associated with AMI, so immediate bypass surgery should be provided. d. Positive likelihood ratio associated with the CT angiogram: LR+ = sensitivity / (1- specificity) = 0.95/ (1- 0.90) = 9.5 e. Negative likelihood ratio associated with the CT angiogram: LR- = (1 – sensitivity) / specificity = (1 – 0.95) / 0.9 = 0.0556 f. Pre-test odds = pretest probability / (1- pretest probability) = 0.06/ (1- 0.06) = 1.5 g. Post-test odds of MI with a positive CT angiogram: = pretest odds x LR+ = 1.5 x 9.5 = 14.25 h. Post-test odds of MI with a negative CT angiogram: = Pretest x LR- = 1.5 x 0.0556 = 0.0834 i. Post-test probability of MI with a positive CT angiogram: = post-test odds / (1+ post-test odds) = 14.25/ (1+ 14.25) = 0.934 j. Post-test probability of MI with a negative CT angiogram: = 0.0834/ (1+ 0.0834) = 0.077 k. No treat-test low threshold= Harm x (1-specificity)/ harm x (1- specificity) + benefit x sensitivity = 0.05 x (1- 0.9)/ 0.05 x (1-0.9) + 0.2x