Evidence Based Practice: Unit II Asking and Answering Clinical Questions: Diagnosis

1. Evidence Based Practice: Unit II Asking and Answering Clinical Questions: Diagnosis Mount St. Mary’s College Doctor of Physical Therapy Program Faculty Online Instruction

2. Asking Clinical Questions Objectives: • Understand the difference between background and foreground questions. • Understand the need for background and foreground questions in physical therapy education. • Given a patient scenario write an answerable question related to diagnosis, prognosis, intervention and outcomes using the PICO method.

3. . • Domain V • Evaluate Use of evidence • Assess EBP skills and use of evidence. • Share and store critical appraisals • Monitor literature for new evidence Identify Learning or Developmental Need . • Domain I • Ask Focused Questions • Identify category of evidence (Diagnosis, Prognosis, Intervention) • Formulate four-part clinical question Client/Patient Problem EBP begins and ends here! Domain IV Apply Findings Interpret evidence in the context of the specific issues related to the client/patient problem. • Domain II • Search for Evidence • Use evidence hierarchy to guide search: • Search for meta-analyses, systematic reviews first. • Search primary literature • Domain III • Critically Appraise Evidence • What is the level of evidence? • Is the evidence valid? • Are the results important? Modified by Slavin, 2005

4. Client/Patient ProblemEBP begins and ends here! • A patient problem that cannot be answered with existing knowledge. • A challenge to one’s own existing knowledge– does literature support our best judgment??

5. Identify Learning or Developmental Need • Diagnosis • Prognosis • Therapy (Intervention)

6. Identify Learning or Developmental Need • Diagnosis • Examination • Evaluation

7. Domain IAsk Focused Questions • Formulate a focused clinical question • P atient, population, problem • I ntervention, prognostic factor, or exposure • C omparison or alternative intervention • O utcome to measure or achieve

8. Domain IISearch for Evidence • Use evidence hierarchy to guide search: • Search for meta-analyses, systematic reviews first. • Search primary literature • PubMed’s Clinical Queries & Cochrane Library are useful tools.

9. Systematic Reviews and Meta-Analyses Randomized Controlled Trials Cohort Studies Case Control Studies Opinions, Letters Animal Research In vitro Research

10. Sensitivity and Specificity • Do patients who REALLY have the condition prove to be positive on the test? (Sensitivity) • Do patients who REALLY do NOT have the condition, prove to be negative on the test? (Specificity)

11. Sensitivity • The proportion of times that the test is positive in patients who have the pathology. • True Positives • Sensitivity = True Positives False Positives + True Positives Loong (2003.)

12. Specificity • Proportion of times that the test is negative in patients without the pathology. • True Negatives • Specificity = True Negatives False Negatives + True Negatives Loong (2003.)

13. Person without the disease Person with the disease NATURAL FREQUENCIES GRID Assume that the prevalence of the disease is 4% Loong (2003.)

14. Person without the disease Person with the disease Person who tests positive Person who tests negative Assume that of the 4 people with the disease, 3 are picked up by the test Loong (2003.)

15. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test Assume that the test is positive for a further 7 people who don’t have the disease (11 total) Loong (2003.)

16. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test True negative on the test False negative on the test The remainder of the sample are negative on the test Loong (2003.)

17. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test True negative on the test False negative on the test SENSITIVITY • SENSITIVITY is the proportion of people with the disease correctly identified by the test • It measures the proportion of false NEGATIVES Loong (2003.)

18. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test True negative on the test False negative on the test SENSITIVITY In this case, sensitivity is ¾ or 75% Loong (2003.)

19. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test True negative on the test False negative on the test SPECIFICITY • SPECIFICITY is the proportion of people without the disease correctly identified by the test • It measures the proportion of false POSITIVES Loong (2003.)

20. Person without the disease Person with the disease Person who tests positive Person who tests negative True positive on the test False positive on the test True negative on the test False negative on the test SPECIFICITY In this case, specificity is (96-7)/96 or 93% Loong (2003.)

21. Domain IIICritically Appraise Evidence • What is the level of evidence? • Is the evidence valid? • Are the results important?

22. Diagnosis • Was there an independent blind comparison with a reference (“gold”) standard of diagnosis. • Was the diagnostic test evaluated in an appropriate spectrum of patients (like those in whom we would use it in practice)? • Was the reference standard applied regardless of the diagnostic test result? • Was the test (or cluster of tests) validated in a second independent group of patients?

23. Critiquing Tests, Measures • Criteria for a “strong” test. • Objective • Valid • Reliable • Sensitive/Specific • Ceiling/Floor Effects • Clinical Utility • Based on more than our respect for the author of the measure.

24. Empty Can vs. Full Can Itoi et al., Am J of Sports Med, 27:65-68, 1999

25. Domain IVApply Findings Interpret evidence in the context of the specific issues related to the client/patient problem.

26. Should I apply this valid test to my patient? • Is the diagnostic test available, affordable, accurate, and precise in our setting? • Can we generate a clinically sensible estimate of our patient’s pre-test probability • Will the resulting post-test probabilities affect our management and help our patient?

27. Domain VEvaluate Use of evidence • Assess EBP skills and use of evidence. • Share and store critical appraisals (CATs) • Monitor literature for new evidence

28. Diagnosis Summary • Ask patient focused question • Find the literature • Assess tests and measures • Sensitivity/Specificity • Valid/Reliable • Share with colleagues • Evaluate