Hazard ratio | EPFL Graph Search

In survival analysis, the hazard ratio (HR) is the ratio of the hazard rates corresponding to the conditions characterised by two distinct levels of a treatment variable of interest. For example, in a clinical study of a drug, the treated population may die at twice the rate per unit time of the control population. The hazard ratio would be 2, indicating higher hazard of death from the treatment. A scientific paper might utilise a Hazard Ratio (HR) to state something as follows. "Adequate COVID-19 vaccination status was associated with significantly decreased risk for the composite of severe COVID-19 or mortality with a[n] HR of 0.20 (95% CI, 0.17-0.22)." In layman's English, this means: People in the study who were vaccinated were 80% less likely to get severe Covid-19 or to die, compared to people who weren't vaccinated in the same study. So, for a hazardous outcome (e.g. death), a Hazard Ratio below 1 indicates that the treatment (e.g. vaccination) might be favorable (less hazardous), and the lower it is, the better. The parenthesized part is a range estimate constructed to contain the true hazard ratio 95% of the time, i.e. we would expect 95 of every 100 such range estimates (calculated from different sets of participants) to contain the true hazard ratio. However, in generalized cases, the outcome may not necessarily be hazardous. If the outcome is actually benign (e.g. accepting job offer to end a spell of unemployment), then a hazard ratio greater than 1 is favorable for the treatment of job seeking efforts. Hazard ratios differ from relative risks (RRs) and odds ratios (ORs) in that RRs and ORs are cumulative over an entire study, using a defined endpoint, while HRs represent instantaneous risk over the study time period, or some subset thereof. Hazard ratios suffer somewhat less from selection bias with respect to the endpoints chosen and can indicate risks that happen before the endpoint. Regression models are used to obtain hazard ratios and their confidence intervals.

Associations of genetic and infectious risk factors with coronary heart disease

Jacques Fellay, Christian Axel Wandall Thorball, Zhi Ming Xu, Flavia Aurelia Shoko Hodel, Roxane De La Harpe

Coronary heart disease (CHD) is one of the most pressing health problems of our time and a major cause of preventable death. CHD results from complex interactions between genetic and environmental factors. Using multiplex serological testing for persistent ...

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