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  #1  
Old 01-05-2012
surez18's Avatar
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Default abstract qs

For questions 1-2 please consider the following scenario of a medical student reading a published, peer-reviewed study:
A Lancet article detailing the SCAST study, where the angiotensin-receptor blocker candesartan was studied in a randomized, placebo-controlled, double-blinded trial for the treatment of acute stoke. By seven days, blood pressures were lower in the candesartan group versus placebo [mean blood pressure 147/82 mmHg versus 152/84mmHg, respectively] p<0.0001. In addition, the risk of combined endpoints [vascular death, myocardial infarction, or stoke] at six months appears to the medical student to be higher for candesartan [120 events versus 111 events, respectively] with an adjusted hazard ratio of 1.09, 95% confidence interval of 0.84-1.41; p=0.52.
1. Which one is a correct interpretation of the results?
A. Candesartan is helpful in lowering blood pressure, but is harmful long-term and absolutely shouldnít be used in patients that have had an acute stroke.
B. There is no difference at all between candesartan and placebo. Therefore, other drugs should be used in patients that have had an acute stroke.
C. Candesartan lowers blood pressure, but because the combined endpoints hazard ratio is greater than 1.0, it may cause more harm in patients that have had a stroke.
D. Candesartan is more effective than placebo at lowering blood pressure, but doesnít appear to have any long-term advantages over placebo in preventing the combined endpoints in patients that have had a stroke.
E. Candesartan is more effective than placebo at lowering blood pressure and lowers the long-term incidence of vascular death, myocardial infarction and stroke.


2. Concerning randomization in this clinical trial, which statement is false?
A. The results for short-term lowering of blood pressure are believable because patients with varying blood pressure would likely be distributed between the two treatment arms equally.
B. Even though the study was randomized, it appeared that the candesartan treatment group had more patients with higher risk for endpoints, making the study less believable.
C. Randomization was used to try to eliminate selection bias in the determination of treatment for patients.
D. Randomization can fail by chance, and groups can be different at baseline.
E. Randomization would likely ensure that patients with unknown cardiovascular risks for study endpoints werenít placed in one treatment group more than another.

i found this qs in some forum. it ll help to get an idea abt new type ck qstn.
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Old 01-06-2012
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what re the ans??
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Old 01-06-2012
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For the first qn logically D seems be right, but 5 mm Hg difference..is it clinically relevant? if not - than B is answer

For second one - B?
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Old 01-08-2012
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the ans for the first q..is C
for the second question is B.
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Old 01-09-2012
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Correct Answer answers

1.Answer: D
The p-value for statistical significance in clinical trials is usually p<0.05. Since the p<0.0001 for short-term blood pressure differences, the difference is statistically significant and likely real. However, the hazard ratio for endpoints has two pieces of evidence that there is no difference in combined endpoints between the two groups: p=0.52 and the confidence interval for the hazard ratio analysis includes 1.
2.Answer: B
Randomization in clinical trials is performed to eliminate selection bias. Randomization can by chance lead to unequal groups at baseline, but can be corrected for, statistically. Unexplained results donít mean that randomization didnít work.
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