Comparative Analysis of Frequently Suspected Drugs for Adverse Drug Reactions in the Spontaneous Reporting System Versus in a Prospective Multicenter Cohort Study in Hospital Emergency Departments

Background/Objectives: The pharmacovigilance aims to identify, assess and minimize drug risks. Therefore, spontaneous reports play a central role. However, the high level of underreporting and the varying data quality are limitations that should be minimized by prospective cohort studies. Methods: The spontaneous reports reported to the Drug Commission of the German Medical Association (AkdÄ) within one year were compared with the adverse drug reaction (ADR) cases systematically recorded in the hospital emergency departments. The frequencies of the demographic patient characteristics and the odds ratios as the relationship between suspected and concomitant medication were calculated. Results: In the spontaneous reports, the reported cases were a median of 12 years younger, and the group of very old people was less strongly represented (10.8% versus 27.3% in the prospective cohort study). Within the study, cases with polypharmacy were documented significantly more often (median 7 drugs [IQR 3;10] versus median 2 drugs [IQR 1;5] in the spontaneous reports). New drugs and drugs discussed in the media were frequently reported as causing ADRs, whereas drugs with an effect on the central nervous system were more often suspected in the emergency department setting. Conclusions: Both sources of ADRs provide complementary information that can improve risk signal detection. The aim for the future is to further increase awareness of spontaneous reports and to identify specific issues using structured investigations.