Difference between revisions of "Hazard ratio"
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*The hazard ratio is the ratio of (chance of an event occurring in the treated group)/(chance of an event occurring in the control group). | *The hazard ratio is the ratio of (chance of an event occurring in the treated group)/(chance of an event occurring in the control group). | ||
| − | *The hazard ratio is the ratio of (risk of outcome in one group)/(risk of outcome in the control group), occurring in a certain interval of time. | + | *The hazard ratio is the ratio of (risk of outcome in one group)/(risk of outcome in the control group), occurring in a certain interval of time |
| + | ==Example== | ||
| + | In a study showing the effectiveness of [[hydroxychloroquine]] to treat [[COVID-19]], French researchers considered the outcomes of 3,737 COVID-19 patients and found that:<ref>https://www.sciencedirect.com/science/article/pii/S1477893920302817 | ||
| + | </ref> | ||
| + | {{cquote|Treatment with HCQ-AZ was associated with a decreased risk of transfer to ICU or death (Hazard ratio (HR) 0.18 0.11–0.27), decreased risk of hospitalization ≥10 days and shorter duration of viral shedding.}} | ||
==References== | ==References== | ||
{{reflist}} | {{reflist}} | ||
[[category:Probability and Statistics]] | [[category:Probability and Statistics]] | ||
Revision as of 16:36, July 5, 2020
Hazard ratio ("HR") is a quantity often used in medical studies to show a decrease in risk of mortality or harm from using the studied course of treatment. A hazard ratio of 1 signifies no change, while a hazard ratio of 0.5 signifies a 50% reduction in harm.
In other words, the hazard ratio is the risk of a hazard relative to a control group risk of 1.
The hazard ratio is defined formally in two different ways:[1]
- The hazard ratio is the ratio of (chance of an event occurring in the treated group)/(chance of an event occurring in the control group).
- The hazard ratio is the ratio of (risk of outcome in one group)/(risk of outcome in the control group), occurring in a certain interval of time
Example
In a study showing the effectiveness of hydroxychloroquine to treat COVID-19, French researchers considered the outcomes of 3,737 COVID-19 patients and found that:[2]
| “ | Treatment with HCQ-AZ was associated with a decreased risk of transfer to ICU or death (Hazard ratio (HR) 0.18 0.11–0.27), decreased risk of hospitalization ≥10 days and shorter duration of viral shedding. | ” |