EBM STUDY DESIGN PRACTICE QUESTIONS
Study Design
•A community assesses a random sample of its residents by telephone questionnaire.
Obesity is strongly associated with diagnosed diabetes. - Answers :cross sectional
Study Design
•A study to determine whether treatment with an angiotensin-converting enzyme
inhibitor (Ace-I) lowers the incidence of coronary heart disease when compared with a
diuretic included over 33,000 patients (ALLHAT 2002). Patients at risk of coronary heart
disease were randomized to receive either an Ace-I or a diuretic and the primary
outcome was how many patients in each group suffered a fatal coronary heart disease
or myocardial infarction. - Answers :Randomized Control Trial
Study Design
•You may remember that three years ago there was a multistate outbreak of illnesses
caused by a specific and unusual strain of Listeria monocytogenes. As part of the
investigation of this outbreak, CDC workers checked the food histories of 20 patients
infected with the outbreak strain and compared them with the food histories of 20
patients infected with other Listeria strains. - Answers :Case-Control
Types of Bias
•A study wants to see if a new medication can help treat patients who are in chronic
pain.
•It is an open label study where half of the patients are given the medication and half
are given the placebo?
•Which type of bias is most prevalent in this study? - Answers :Performance Bias
Study Design
•The initial studies establishing maternal diethylstilbesterol(DES) intake as a cause of
vaginal adenocarcinoma in female offspring were case-control studies. This was
probably largely because
A. a couple of decades ago cohort studies hadn't been invented.
B. a woman taking DES was always rare.
C. The disease outcome is rare.
D. The investigators had probably just happened to have a number of cases in their
practices. - Answers :c
Study Design
Study Design
•A community assesses a random sample of its residents by telephone questionnaire.
Obesity is strongly associated with diagnosed diabetes. - Answers :cross sectional
Study Design
•A study to determine whether treatment with an angiotensin-converting enzyme
inhibitor (Ace-I) lowers the incidence of coronary heart disease when compared with a
diuretic included over 33,000 patients (ALLHAT 2002). Patients at risk of coronary heart
disease were randomized to receive either an Ace-I or a diuretic and the primary
outcome was how many patients in each group suffered a fatal coronary heart disease
or myocardial infarction. - Answers :Randomized Control Trial
Study Design
•You may remember that three years ago there was a multistate outbreak of illnesses
caused by a specific and unusual strain of Listeria monocytogenes. As part of the
investigation of this outbreak, CDC workers checked the food histories of 20 patients
infected with the outbreak strain and compared them with the food histories of 20
patients infected with other Listeria strains. - Answers :Case-Control
Types of Bias
•A study wants to see if a new medication can help treat patients who are in chronic
pain.
•It is an open label study where half of the patients are given the medication and half
are given the placebo?
•Which type of bias is most prevalent in this study? - Answers :Performance Bias
Study Design
•The initial studies establishing maternal diethylstilbesterol(DES) intake as a cause of
vaginal adenocarcinoma in female offspring were case-control studies. This was
probably largely because
A. a couple of decades ago cohort studies hadn't been invented.
B. a woman taking DES was always rare.
C. The disease outcome is rare.
D. The investigators had probably just happened to have a number of cases in their
practices. - Answers :c
Study Design
