Absolute and relative risks of participants reporting specific AEs

7 Absolute and relative risks of participants reporting specific AEs 

Similar analysis approaches are used to describe the risk, in both the absolute and relative (comparative) sense, of individuals reporting specific AEs. These analyses are much more useful clinically because not all AEs are created equal. One example is to estimate the proportion of individuals in a given group who reported a headache. To do this in a standardized manner it is necessary to code the AE descriptions (for example, tension headache , achy head ). The use of the MedDRA coding dictionary for this purpose is now widely accepted, and in some instances may be required. Coding is performed before statistical analysis and the coded terms are used in statistical summaries that require counting of participants reporting each event. 

For example, if 25 participants received treatment A and, among them, 5 reported a headache, the estimated proportion of participants reporting a headache is 5/25 = 0.20, which can also be expressed as 20%. When such an analysis is repeated for all AEs reported, and the quantities are expressed as percentages and displayed in tabular form in a package insert, it is relatively easy for prescribing physicians and their potential patients to answer their questions. 

Suppose that an investigational antihypertensive drug is evaluated at multiple doses in a parallel-group placebo-controlled study. Participants in this therapeutic exploratory study were randomly assigned to receive either placebo or one of three possible doses of the test treatment (low, medium, or high). The treatment period was for 6 weeks. The number and percentage of participants experiencing any AE, and particular AEs, are displayed in Table 8.2. 

Chapter 8 Confirmatory clinical trials Safety data I 

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