1 / 25

MARIEL LOPEZ & MARITZA RENEAU Foreign Languages

MARIEL LOPEZ & MARITZA RENEAU Foreign Languages. Warm-Up. Identification and Classification of Outcome Medical condition Psychological or social problem Positive Identification of Exposure Higher probability Protective effect. Warm-up. Outcome.

rickyy
Download Presentation

MARIEL LOPEZ & MARITZA RENEAU Foreign Languages

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. MARIEL LOPEZ & MARITZA RENEAU Foreign Languages

  2. Warm-Up • Identification and Classification of Outcome • Medical condition • Psychological or social problem • Positive • Identification of Exposure • Higher probability • Protective effect

  3. Warm-up Outcome Risk Factor-Possible effect

  4. Warm-up Outcome Risk Factor-Possible effect

  5. Warm-up • Enduring Epidemiological Understanding: Making group comparison and identifying association • General model • Specific model : Smoking and lung cancer

  6. Warm-up Association of interest Exposure Disease

  7. Warm-up Association of interest Smoking Lung cancer • What do you think is the best method to demonstrate a causal relation? Choose the best answer • Experimental study • Observational study.

  8. Warm-up Association of interest Smoking Lung cancer • What do you think is the best method to demonstrate a causal relation? Choose the best answer • Observational study. Choose the best answer • Case-control • Cohort • Cross-sectional

  9. Warm-up • Cohort study- handout • Design • Advantages and disadvantages

  10. Warm-up Association of interest Smoking Lung cancer • Can you think of some examples of other exposures or lifestyle choices that might be the real culprits in causing lung cancer?

  11. Enduring Epidemiological Understanding • Explaining Association and Judging Causation

  12. LESSON OBJECTIVES • To Understand Confounding • To Calculate and Interpret Relative Risk • To use Stratification in order to Identify Confounding Variables • In what phase of the study can stratification be used? • Design • Analysis

  13. Introduction- Confounding VariableBedsores and Mortality Association of interest Mortality Bedsores Medical Severity CV • Can you think of some examples of other exposures or lifestyle choices that might be the real culprits in causing Mortality?

  14. Bedsores and Mortality Study • Objective: The association between bedsores and death among elderly hip fracture patients. • Sample: 9,400 patients aged 60 and over, admitted with hip fracture to one of 20 study hospitals. • Methods: Medical charts were reviewed by research nurses in order to identify exposure and outcome.

  15. Analysis – Bedsores and MortalityRR- Unadjusted

  16. Analysis – Bedsores and MortalityRR- Unadjusted RR=.096/.033=2.9

  17. Introduction- Confounding VariableBedsores and Mortality Association of interest Mortality Bedsores Medical Severity CV • Can you think of some examples of other exposures or lifestyle choices that might be the real culprits in causing Mortality?

  18. Analysis – Bedsores and MortalityAdjusted by Medical Severity (PCV) RR U=.096/.033=2.9 High Medical Severity Group – 5 or more diseases when admitted to hospital RR=55/106= 1.04 5/10 Low Medical Severity Group- <5 RR=24/718= 1.02 281/8,566

  19. Bedsores and MortalityPCV Medical Severity • Is Medical Severity a confounding variable? • According to the stratification analysis…. • According to the definition • CV Outcome • We would expect that the people with HMS would have a higher probability of death that people with LMS • CV RF • We would expect that people with HMS would have a higher probability of bedsores that people with LMS.

  20. Analysis – Bedsores and MortalityAdjusted by Medical Severity (PCV) MS Mortality High Medical Severity Group – 5 or more diseases when admitted to hospital Proportion of HMS who died= 60/116= 51.7% Low Medical Severity Group- <5 Proportion of HMS who died= 305/9,284= 3.3%

  21. Analysis – Bedsores and MortalityAdjusted by Medical Severity (PCV) MS Bedsores High Medical Severity Group – 5 or more diseases when admitted to hospital Proportion of people with bedsores among those with HMS 106/116= 91.4% Low Medical Severity Group- <5 Proportion of people with bedsores among those with LMS 718/9,284= 7.7%

  22. Conclusion • The fact that the adjusted RR was different from the unadjusted RR is evidence that there is confounding. • Another symptom of confounding was identified by showing that there was an association both between bedsores and MS and dying and MS. • There was no association between bedsores and mortality.

  23. More….. • In our example, there is confounding by MS but does that mean that the association between bedsores and dying is not real? • If your answer is no, why do you say so?

  24. More….. • In our example, there is confounding by MS but does that mean that the association between bedsores and dying is not real? Answer: No. Patients with bedsores really do have a higher risk of dying but it is not because they have bedsores. Bedsores are guilty by association!

  25. Activity • Student handout

More Related