Summarizing the Incidence of Adverse Events Using Volcano Plots
Geoffrey C. Mann, JMP Life Sciences, SAS Institute, Inc.  Russ Wolfinger, SAS  *Richard C. Zink, JMP Life Sciences, SAS Institute, Inc. 

Keywords: Adverse events, graphics, incidence, multiple comparisons, safety

It can be challenging to perform a concise and easily-interpretable analysis of adverse events (AEs). For therapeutic areas where patients have frequent AEs, understanding the safety profile of a new intervention is critical. In these instances, however, understanding the analysis is made more difficult by the sheer number and variety of AEs that occur. Traditionally, the incidence of adverse events is presented in lengthy tables, with coded AE terms grouped by body system or system organ class and presented in order of descending frequency. We propose the use of volcano plots for the analysis of adverse events. Volcano plots have numerous benefits in that they are space-saving, can easily incorporate and display multiplicity adjustments, and can accentuate changes in risk over time. Perhaps most important, volcano plots emphasize important safety findings while minimizing noise, thus aiding in the interpretation of large amounts of information for the clinical study report or safety review. We illustrate the use of volcano plots with an analysis of adverse events from a clinical trial of delayed cerebral vasospasm in patients who experienced an aneurysmal subarachnoid hemorrhage. Finally, we describe how volcano plots can be applied to other areas of safety analysis such as laboratory abnormalities and concomitant medications.