Match each clinical study scenario with the most appropriate epidemiological measure of disease frequency or association.
- A prospective cohort study follows 1,000 initially healthy adults for 5 years to determine the proportion that develops incident hypertension.Cumulative Incidence
- A case-control study identifies adults with hepatocellular carcinoma and age-matched healthy volunteers, then surveys them regarding previous hepatitis C infection.Odds Ratio
- A trial compares a new antihypertensive to placebo; the rate of stroke is 3% in the intervention arm and 5% in the placebo arm, with the researchers reporting the 2% difference.Absolute Risk Reduction
- A randomized controlled trial reports that 15 patients must be treated with a novel lipid-lowering medication to prevent one major adverse cardiac event.Number Needed to Treat
Answer
Prospective tracking measures Cumulative Incidence; Case-control studies use Odds Ratio; The simple difference in event rates is the Absolute Risk Reduction; The number of patients treated to prevent one event is the Number Needed to Treat.
Each study design conceptually maps to a specific metric. Cohort studies follow at-risk populations to determine incidence. Case-control studies require the odds ratio due to an inability to measure true incidence. Simple subtraction of adverse event rates between trial arms produces the absolute risk reduction, and identifying how many patients must be treated to prevent one event is the number needed to treat.
Step-by-Step Solution
Key Concept
Epidemiological study designs dictate which measures of disease frequency and association can be mathematically and logically applied.