| Evidence-Based Medicine Case 2 | |||||||||||||||||||||
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| Addis and Koren carried out a meta-analysis to examine the safety of the anti-depressant SSRI fluoxetine during the first trimester of pregnancy. Specifically, they searched for prospective unpublished and published data which examined whether there is an increased risk of malformations associated with the use of fluoxetine during the first trimester. Four studies met their eligibility criteria and were included in the analysis: two prospective studies with a control group and two studies without a control group. See this paper as: Addis and Koren. Safety of fluoxetine during the first trimester of pregnancy: a meta-analytical review of epidemiological studies. Psychological Medicine 2000, 30:80–94. A. Why did the authors exclude retrospective studies from their overview? (Think of the possible biases which are related to the retrospective design). B. The authors report that the weighted average of the relative risk for major malformations was 2.6% (95% CI 1–4.2) and this figure represents the ratio of the number of infants with major malformations to the number who were live-born. What this number tell you about the safety of the use of fluoxetine during the first trimester of pregnancy?
C. Two of the original studies included used the same kind of control groups, consisting of women exposed during the first trimester to drugs and procedures not considered teratogenic (e.g. acetaminophen, dental radiography) Do you agree with this kind of control group? What would be the difference if they had used as controls pregnant women who were not exposed at any drug or procedure? What would be the ideal control group.
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