Question of the Week #482

RESEARCH ABSTRACT QUESTION #1

BACKGROUND:

Aldosterone blockade reduces mortality and morbidity among patients with severe heart failure. We conducted a double blind, placebo-controlled study evaluating the effect of eplerenone, a selective aldosterone blocker, on morbidity and mortality among patients with acute myocardial infarction complicated by left ventricular dysfunction and heart failure.

METHODS:

Patients were randomly assigned to eplerenone (25 mg per day initially, titrated to a maximum of 50 mg per day; 3319 patients) or placebo (3313 patients) in addition to optimal medical therapy. The study continued until 1012 deaths occurred. The primary end points were death from any cause and death from cardiovascular causes or hospitalization for heart failure, acute myocardial infarction, stroke, or ventricular arrhythmia.

RESULTS:

During a mean follow-up of 16 months, there were 478 deaths in the eplerenone group and 554 deaths in the placebo group (relative risk, 0.85; 95 percent confidence interval, 0.75 to 0.96; P=0.008). Of these deaths, 407 in the eplerenone group and 483 in the placebo group were attributed to cardiovascular causes (relative risk, 0.83; 95 percent confidence interval, 0.72 to 0.94; P=0.005). The rate of the other primary end point, death from cardiovascular causes or hospitalization for cardiovascular events, was reduced by eplerenone (relative risk, 0.87; 95 percent confidence interval, 0.79 to 0.95; P=0.002), as was the secondary end point of death from any cause or any hospitalization (relative risk, 0.92; 95 percent confidence interval, 0.86 to 0.98; P=0.02). There was also a reduction in the rate of sudden death from cardiac causes (relative risk, 0.79; 95 percent confidence interval, 0.64 to 0.97; P=0.03). The rate of serious hyperkalemia was 5.5 percent in the eplerenone group and 3.9 percent in the placebo group (P=0.002), whereas the rate of hypokalemia was 8.4 percent in the eplerenone group and 13.1 percent in the placebo group (P<0.001).

  1. Which of the following statements represents the most accurate interpretation of the results from the aforementioned clinical trial?
    1. There was no significant difference in the incidence of hyperkalemia between trial arms.
    2. There was no significant difference in the rate of sudden cardiac death between trial arms.
    3. Epleranone, when added to optimal medical therapy, decreases all cause mortality in patients with left ventricular dysfunction following myocardial infarction.
    4. The rate of hypokalemia was not significantly different between trial arms.
    5. The most common causes of death seen in enrolled patients over the course of this trial were non-cardiac in nature.

Question of the Week #474

474. A cohort study is done concerning the relationship between exposure to oral contraception and the risk of breast cancer. 1000 women were followed from 2003 to 2007. Results are listed below:

Breast Cancer + Breast Cancer –
Oral contraceptive + 300 (a) 200 (b) a + b = 500

Probability of breast cancer among exposed: 300/500 = 0.6

Oral Contraceptive – 100 © 400 (d) c + d = 500

Probability of breast cancer among those not exposed = 100/500 = 0.2

a + c = 400 b + d = 600

Which of the following represents the absolute risk reduction of breast cancer in women who do not use oral contraceptives?

  1. 75%
  2. 67
  3. 40%
  4. 50%
  5. 30%

Question of the Week # 473

  1. You are reading a study that was conducted to evaluate IQ (intelligence quotient) scores for patients with bipolar disease. Ten patients did not complete the test. Two patients refused to begin the test. Results for the 94 patients who completed the test revealed an average IQ of 130 with a standard deviation of 20. Which of the following best represents the 95% confidence interval for this study?
  1. 4
  2. 2
  3. 1
  4. .05
  5. .1

Question of the Week # 469

A study is performed to evaluate the incidence of peri-operative stroke during a carotid endarterectomy based on whether the surgeon uses a shunt during the procedure or not. The authors calculate the odds ratio of suffering from stroke if the surgeon uses a shunt is 0.84 (95% CI: 0.72 – 1.12) compared to when the surgeon does not use a shunt. What is the most appropriate interpretation of this finding?
A. Use of shunt decreases risk of stroke by 84%
B. Use of a shunt does not decrease or increase risk of stroke
C. Use of shunt does not decreases the risk of stroke
D. Use of shunt decreases risk of stroke with a 0.84 odds ratio
E. Use of shunt decreases risk of stroke by 16%

Question of the Week # 461

Q461) A clinical trial is evaluating an investigational new drug (Drug A) as compared with standard therapy (Drug B) in patients presenting to the emergency department with myocardial infarction (MI). The study enrolled a total of 3,000 subjects, 1,500 in each study arm. Follow-up was conducted at 45 days post-MI. The following are the results of the trial:

Endpoints Drug A Drug B P-Value
Primary:

·         Death from cardiovascular causes

134 210 0.03
Secondary:

·         Hyperkalemia

57 70 0.4

What is the relative risk of death from cardiovascular cause? (Round to the nearest whole number)

A. 36%
B. 42%
C. 57%
D. 64%
E. 72%
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