Hazard Ratio (HR): How to Read It on a Drug Label
[Glossary · Quality, storage and rules]

Hazard ratio

Also called HR, hazard ratios · Reviewed

Definition: A hazard ratio (HR) compares how often an event happens over time in one group with how often it happens in another. The NCI says a hazard ratio of 1 means no difference between the groups. Above 1, the event happened more often in the first group; below 1, less often.

Hazard ratios on labels

Hazard ratios printed on three current US labels
Label and comparisonEvent ratesHazard ratio (95% CI)
Evenity vs alendronate, major heart events2.0% vs 1.1%1.87 (1.11 to 3.14)
Evenity vs placebo, major heart events0.8% vs 0.8%1.03 (0.62 to 1.72)
Egrifta SV vs placebo, HbA1c reaching 6.5% or higher by week 265% vs 1%3.3 (1.4 to 9.6)
Actos vs placebo, bladder cancer over 13 years of trial and follow-upDid not differ1.00

The labels print a range in brackets (the 95% confidence interval) next to most ratios. For Evenity against placebo the range runs from 0.62 to 1.72, on both sides of 1.

A worked reading

Evenity against alendronate

  1. The ratio is 1.87, above 1, so major heart events happened more often in the Evenity group.
  2. The event rates were 2.0% and 1.1%, a gap of 0.9 percentage points.
  3. Both numbers describe the same result: one as a ratio, one as a difference. See relative vs absolute risk.

Why it matters for your log

A hazard ratio describes groups in a trial, not what will happen to one person. Your log of doses and any events is what your prescriber can weigh against it.

Read more on Dose Track: Evenity side effects · Egrifta SV side effects · Actos side effects · Prolia vs Evenity

General education drawn from labels and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your product are the final word.

Frequently asked questions

What does a hazard ratio of 1 mean?+
The NCI says a hazard ratio of 1 means there is no difference between the two groups for that event.
Is a hazard ratio of 2 a 2% risk?+
No. It is a ratio between groups, not a percentage. On the Evenity label, a hazard ratio of 1.87 went with event rates of 2.0% and 1.1%.