Causal analysis in comparative effectiveness research  Slides►
Assigned reading What do you know? Do one More

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What do you know?

Advanced learners like you, often need different ways of understanding a topic. Reading is just one way of understanding. Another way is through writing about what you have read.  The following questions get you to think more about the concepts taught in this session.

1. Discuss how the paper on impact of Vioxx established the causal link between the medication and mortality.  In particular, what steps did the paper take to check for the counterfactual argument that patients who had died would not have died if they had not taken Vioxx.
2. Did moderate use of Vioxx lead to higher cardiac events than other pain medications?  Was there a difference in type of patients that received high-dose Vioxx and other medications?  Could these differences explain the association between Vioxx and cardiac events?
3. Discuss how the paper on impact of Vioxx established risk score for various cardiac risk factors.  Did they adequately account for interaction among the risk factors?  What evidence is there that the adjustment for severity was adequate?
4. Besides association between two events, what else needs to be verified before it can be inferred that one of the variables is causing the occurrence of the other?
5. Describe the HCUP data? 
6. Describe the limitations of Quality Indicators developed by the Agency for Health Care Quality and Research.
7. What is meant by counterfactual?  In testing if a medication has led to excess mortality, how would the measurement of severity of illness help establish counterfactual claim that patients would have lived if it were not for the medication.
8. What is APR-DRG?  Describe the data used for creating the APR-DRG. 
9. Assume that the severity of CHF, MI, Diabetes, Hypertension, alcohol use, and ACL surgery are scored as 0.9, 0.8, 0.5, 0.1, 0.3, and 0.75.  Assess the overall severity of the ten cases in Table 1.  Plot the patient's length of stay against the patient's severity of illness.  Is there a patient whose length of stay does not follow what might be expected from his/her severity of illness:
   

   Case	1st Diagnosis	2nd Diagnosis	3rd Diagnosis	4th Diagnosis	5th Diagnosis	Length of stay
   1	MI	CHF				5
   2	MI					2
   3	MI	CHF	Diabetes			6
   4	MI	CHF				7
   5	CHF	Diabetes				4
   6	MI	Hypertension				2
   7	ACL surgery					1
   8	MI	Diabetes	CHF	Hypertension	Alcohol use	6
   9	MI	Alcohol use				3
   10	CHF					3
   Table 1:  Sample Claims Data for 10 Cases MI = Myocardial Infarction; CHF = Congestive Heart Failure; ACL =  Anterior Cruciate Ligament