1.The similarity of treatment groups with respect to baseline chara...

1.The similarity of treatment groups with respect to baseline characteristics most likely occurred because of
A.Use of intention-to-treat analysis
B.The placebo effect
C.Use of randomization
D.Use of blinding
E.Use of informed consent

2.One control in ten had a clinical response.This is best explained by
A.Use of intention-to-treat analysis
B.The placebo effect
C.Use of randomization
D.Use of blinding
E.Use of informed consent

3. Neither patients nor clinicians who evaluated them knew individual treatment assignments.This may be described as
A.Use of intention-to-treat analysis
B.The placebo effect
C.Use of randomization
D.Use of blinding
E.Use of informed consent

4. The results suggest that compared with controls, patients treated with memantine have
A.Better clinical response and fewer serious adverse effects
B.Better clinical response, but more serious adverse effects
C.Worse clinical response, but fewer serious adverse effects
D.Worse clinical response and more serious adverse effects
E.The same clinical response, but fewer serious adverse effects

5. Although more controls than patients treated with memantine failed to complete the study, all patients were analyzed according to the original assignment. This is best described as
A.Use of intention-to-treat analysis
B.The placebo effect
C.Use of randomization
D.Use of blinding
E.Use of informed consent

6. Some patients may have enrolled with cognitive deficits great enough to impair their understanding of the purpose and risks of the study. In these instances, caregivers represented the patients in accepting the risks and benefits of the study. This process is best described as
A.Use of intention-to-treat analysis
B.The placebo effect
C.Use of randomization
D.Use of blinding
E.Use of informed consent

II 1. In a case-controlled study of the relationship of dietary intake of fruits and vegetables and the risk of developing hypertension, the control subjects are sampled from the participants at a health fair.
A.Selection bias
B.Non-differential misclassification
C.Confounding
D.Ecologic fallacy
E.Random error

2.In a case-control study of inflammation and the development of coronary heart disease, 20-year-old stored frozen blood specimens are used to measure C-reactive protein in cases and controls.There is concern that during storage the specimens have deteriorated, yielding lower levels than when they were first obtained.
A.Selection bias
B.Non-differential misclassification
C.Confounding
D.Ecologic fallacy
E.Random error

3.In a cohort study of hormone replacement therapy and the risk of developing atherosclerotic coronary disease, high socioeconomic status is associated with both use of hormone replacement therapy and risk of developing coronary artery disease.
A.Selection bias
B.Non-differential misclassification
C.Confounding
D.Ecologic fallacy
E.Random error

4.In a case-control study of alcohol consumption and the risk of hepatocellular carcinoma, both cases and controls underreport exposure to alcohol.
A.   Selection bias
B.   Non-differential misclassification
C.   Confounding
D.   Ecologic fallacy
E.   Random error

5.In a cohort study of the effect of obesity on the development of left ventricular hypertrophy, the investigator reviewing the echocardiogram is blinded to whether the subject is obese or not.
A.Overestimation
B.Underestimation
C.No effect
D.Cannot be determined

6.In a cohort study of obesity and the risk of development of type 2 diabetes, the loss to follow-up is 35% among the obese subjects and 15% among the nonobese subjects.
A.Overestimation
B.Underestimation
C.No effect
D.Cannot be determined

7.In a case-control study of the relationship of stressful life events and the occurrence of coronary artery disease, patients with coronary aterty disease are more likely to report past stressful events than are the healthy controls.
A.Overestimation
B.Underestimation
C.No effect
D.Cannot be determined

8.Prevalent patients with histories of myocardial infarctions are enrolled in a case-control study of inflammation as measured by C-reactive protein as a risk factor for developing myocardial infarction. Among patients who have had a myocardial infarction, higher C-reactive protein is associated with a higher case fatality rate.
A.Overestimation
B.Underestimation
C.No effect
D.Cannot be determined

9.Individuals with hypertension are randomized to a diuretic, a calcium channel blocker, a B-blocker, and an angiotensin-converting enzyme inhibitor in order to evaluate relative safety and efficacy.
A.Case-control study
B.Cohort study
C.Clinical trial
D.Ecologic study
E.Cross-sectional study

10.The ability to assign by chance the type of anti-hypertensive agent used reduces the likelihood of confounding of diet and physical activity in a study of treatment of blood pressure elevation.
A.Case-control study
B.Cohort study
C.Clinical trial
D.Ecologic study
E.Cross-sectional study

III To study the use of aspirin in the prevention of heart disease and stroke, 5139 doctors were randomly allocated to either a treatment group who took 500 mg aspirin daily or a control group who were given no treatment. The subjects completed a short health questionnaire every6 months for 6 years and certificates were classified by blind assessors (Peto et al. 1988).
1.Was this trial double-blinded? (2-sentence explanation)

IV. One hundred and forty-one babies who developed cerebral palsy were compared to agroup of babies made up from the two babies immediately after each cerebral palsy baby in the hospital delivery book. Hospital notes were reviewed by a researcher who was blind to the baby’s outcome. Failure to respond to signs of fetal distress was noted in 25.8% of the cerebral palsy babies and 7.1% of the delivery book babies (Gaffney et al. 1994
1.What kind of study design is this and what are the advantages and disadvantages of this design?
2.What is meant by blind in this study and why was it done?

V In a study in which a yes/no question was asked on two occasions, 60 per cent of subjects answered yes on each occasion, 20 per cent answered no on each; 10 per cent answered yes on the first test and no on the second, and 10 per cent no, then yes. Present the results on a 2X2 table, calculate Kappa statistic, and provide a description of the level of agreement :

VI A screening test applied to 1000 subjects identifies 100 of them positive. On further investigation, 50 of these are found to have the disease being tested for. In subsequent follow up, 10 of the subjects who tested negative developed the disease within a reasonably short time. Calculate the sensitivity, specificity, and predictive value positive of the test.

VII Using the reference (Nald Prevention of neural tube defects: results of the Medical Research Council vitamin study. Lancet 338: 131-137.) provide short answers to the following questions.
Description of the evidence:
1.What was the exposure or intervention?
2.What was the outcome?
3.What was the study design?
4.What was the study population?
5.What was the main result?

Internal validity—consideration of non-causal explanations
1.Are the results likely to be affected by observation bias? (short explanation)
2.Are the results likely to be affected by confounding? (short explanation)
3.Are the results likely to be affected by chance variation? (short explanation)

Internal validity—consideration of positive features of causation
1.Is there a correct biological time relationship? (short explanation)
2.Is the relationship strong? (short explanation)
3.Is there a dose-response relationship? (short explanation)
4.Are the results consistent within the study? (short explanation)

External validity—generalization of the results
1.Can the study results be applied to the eligible population? (short explanation)
2.Can the study results be applied to the source population? (short explanation)
3.Can the study results be applied to other relevant populations? (short explanation)

Comparison of these results with other evidence
1.Are the results consistent with other evidence, particularly evidence from studies of similar or more powerful study design? (short explanation)
2.Does the total evidence suggest any specificity? (short explanation)
3.Are the results plausible in terms of the biological mechanism? (short explanation)