hazard ratio
Also written as: HR
A measure of treatment effect in time-to-event analyses, comparing the instantaneous risk of events between treatment groups.
Full Definition
Hazard ratios quantify the relative risk of experiencing an event at any given time between treatment and control groups in cardiovascular clinical trials. Unlike risk ratios, hazard ratios account for the timing of events and censored observations, making them ideal for analyzing cardiovascular endpoints like mortality or MACE. A hazard ratio of 0.80 indicates 20% risk reduction in the treatment group compared to control. Hazard ratios are typically estimated using Cox proportional hazards regression, which adjusts for baseline covariates and provides confidence intervals. The proportional hazards assumption should be tested and reported in cardiovascular research.
Usage
Usage note: Always provide confidence intervals and P-values; distinguish from odds ratios and relative risks.
In Context
- "The hazard ratio for cardiovascular death was 0.78 (95% CI: 0.65-0.94; P=0.008)." — Primary results
- "Adjusted hazard ratios were calculated using Cox regression with pre-specified covariates." — Statistical methods