To evaluate a suspected link between maternal fluoxetine use and neonatal pulmonary hypertension, investigators identify 100 neonates diagnosed with this respiratory condition at a tertiary care center over a five-year period. For comparison, they randomly select 400 healthy neonates born at the same center during the same timeframe.
A retrospective review of maternal electronic health records reveals that 20 mothers of affected neonates and 40 mothers of healthy neonates were prescribed fluoxetine during their third trimester.
Which of the following is the most appropriate measure of association for these findings, and what is its calculated value?
- AOdds ratio of
- BRelative risk of
- Odds ratio of Answer
- DRelative risk of
- EOdds ratio of
Answer
Odds ratio of
The study design is a case-control study because participants were selected based on their disease status (neonatal pulmonary hypertension vs. healthy) and their past exposure (fluoxetine) was assessed retrospectively. In case-control studies, disease incidence cannot be measured because the investigator determines the number of cases and controls. Therefore, relative risk cannot be directly calculated. The appropriate measure is the odds ratio. The odds of exposure in cases is (which simplifies to ). The odds of exposure in controls is (which simplifies to ). The odds ratio is .
Step-by-Step Solution
Key Concept
In case-control studies, patients are selected based on outcome status, meaning disease incidence cannot be calculated. Therefore, the odds ratio (OR) is the correct measure of association, not relative risk (RR).
Estimated Time:1m 30s