What does a hazard ratio greater than 1 imply?

• A. It indicates a higher instantaneous risk in the exposed at any time point
• B. It indicates higher cumulative risk over the entire follow-up
• C. It indicates lower risk in the exposed
• D. It indicates no difference in risk over time

Answer: (A)

Hazard ratio compares the instantaneous risk of an event between two groups at any given moment. If this ratio is greater than 1, the exposed group has a higher hazard at any time point, meaning a higher instantaneous risk of experiencing the event. This reflects the short-term, time-specific risk rather than the total amount of risk accumulated over the whole follow-up. So the exposed are at higher instantaneous risk, not lower, and not no difference. If the hazard ratio were less than 1, the hazard would be lower; if it were 1, there would be no difference.