Individual case safety reports--how to determine the onset date of an adverse reaction: a survey.

Background: The building blocks of a pharmacovigilance system depend primarily on good quality individual case safety reports (ICSRs), which are stand-alone summaries describing one or more suspected adverse reactions that occur while a subject is taking either an investigational or marketed medicinal product and may require expedited reporting to regulatory authorities. For regulatory reporting purposes, the information of an ICSR is usually captured on forms such as MedWatch 3500/3500A, CIOMS I, Vaccine Adverse Event Report System (VAERS) or Adverse Events Following Immunization (AEFI). ICSRs that are sent electronically must meet the standards for electronic transmission specified in the International Conference on Harmonisation (ICH) E2B (R2) guideline. In filling out these regulatory forms, there are some areas of ambiguity. One of these is what the 'date of event' (MedWatch) or 'reaction onset date' (CIOMS) is interpreted to be.

Objective: The aim of the survey was to determine the uniformity of responses for the onset date of an adverse reaction.

Methods: A pilot and three surveys of pharmacovigilance professionals were undertaken between February and July 2009 to determine the range of responses for the onset of an adverse reaction. A narrative of a subject admitted to hospital with a diagnosis of pneumonia was presented and the respondent was asked to pick the date of onset of the adverse reaction.

Results: The total number of respondents was 129. The results of the surveys indicated there was considerable variation in responses. These differences were based on different perspectives regarding the suspected adverse reaction. Some viewed the 'reaction' to be the first onset of signs and symptoms (even if non-specific), others considered the onset of the reaction to be the date of the diagnosis, while others considered the date to be when the reaction became serious.

Conclusion: By means of a survey, we have illustrated an example of the variability of determining the onset date of a suspected adverse reaction, and recommend that a criterion for onset time, i.e. beginning of signs or symptoms of the event, or date of diagnosis, be chosen as the standard. Once decided, this information should be incorporated into the company's case assessment documentation and staff appropriately trained, thus ensuring consistency across cases and minimizing the time spent in determining what date to use.