II. Definitions
- Hazard Rate
- First-time event frequency per unit of time (e.g. mortality rate)
- Hazard Ratio
- Frequency of an event or condition in an experimental group as compared with a control group over a specific period of time
- Hazard Ratio = (Exposed Hazard Rate) / (Control Hazard Rate)
- Typically the experimental group is exposed to an event, activity, medication or substance not shared with the control group
- Hazard Ratio <1 suggests a protective effect of the exposure (lower frequency than control group)
- Hazard Ratio >1 suggests a causative or provocative effect associated with the exposure (higher risk than control group)
- In contrast with Odds Ratio and Relative Risk, Hazard Ratios reflect an instantaneous ratio at a specific period in time (e.g. 5 year survival)
- Frequency of an event or condition in an experimental group as compared with a control group over a specific period of time
Images: Related links to external sites (from Bing)
Related Studies
| Definition (NCI_NCI-GLOSS) | A measure of how often a particular event happens in one group compared to how often it happens in another group, over time. In cancer research, hazard ratios are often used in clinical trials to measure survival at any point in time in a group of patients who have been given a specific treatment compared to a control group given another treatment or a placebo. A hazard ratio of one means that there is no difference in survival between the two groups. A hazard ratio of greater than one or less than one means that survival was better in one of the groups. |
| Concepts | Quantitative Concept (T081) |
| English | Hazard Ratio, hazard ratio |
