Relative Risk Case Study

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Relative risk
Relative risk is the ratio of two absolute risks. It measures the strength of effect of an exposure (or treatment) on risk. A beneficial treatment will result in a relative risk of less than 1; this can then be subtracted from 1 to give the relative risk reduction. A harmful treatment, or other exposure, will give a relative risk of more than 1.
Example: In the following study, over 40 years of follow up, the annual mortality rate from CHD was 572 per 100 000 in non-smokers, and 892 per 100 000 in smokers. For lung cancer the figures were 14 and 209, respectively. So the attributable risk of CHD related to smoking was 320 (892−572) per 100 000 compared with 195 (209−14) per 100 000 for lung cancer. These figures are the excess numbers of deaths (per 100 000) in
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As an example, consider the treatment of patients with endocarditis caused by Staphylococcus aureus (SA). Although the mortality rate for this disease ranges from 25% to 47% , let us assume that in the population of interest, White males aged 30 to 60 the mortality rate is 38% with the standard antibiotic treatment of penicillin, methicillin, vancomycin and other antibiotics. However, a new drug has been developed that attacks the bacteria’s ability to protect itself from the human immune system rather than interfering with cell wall development. The question is this: What are the odds of dying with the new drug as opposed to the standard antibiotic therapy protocol? The odds ratio is a way of comparing whether the odds of a certain outcome is the same for two different groups.
The odds ratio is simply the ratio between the following two ratios: The ratio between standard treatment and the new drug for those who died, and the ratio between standard treatment and the new drug for those who survived. From the data in the table 1, it is calculated as follows:

OR = (a/b)/(c/d) =

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