Assessing the Impact on Health of Pharmacovigilance Activities: Example of Four Safety Signals.

Introduction The impact of pharmacovigilance activities on public health remains under-investigated, and measuring the impact on health of pharmacovigilance activities for a specific safety signal is challenging. Objective To gain more insight into the methodological challenges and the data required, we assessed the impact of pharmacovigilance on public health for four identified product-specific safety signals using publicly available data in the Netherlands. The assessment was on the impact of the intertwined and complementary steps of the pharmacovigilance pathways. Methods The impact of pharmacovigilance on public health was assessed using the assessment support tool and 'open data' from the Netherlands for four different types of pharmacovigilance safety signals: (1) off-label use of cyproterone acetate/ethinyloestradiol (CPA/EE) and thrombotic risk after pharmacovigilance measures after 2014; (2) pergolide and the risk of cardiac valvulopathy after pharmacovigilance activities in 2003; (3) proton pump inhibitors and the risk of hypomagnesaemia after pharmacovigilance activities in 2011; (4) rosiglitazone withdrawal from the market because of cardiovascular effects in 2010. Results For the signals on CPA/EE and pergolide, a crude estimation of the impact could be made with varying degrees of assumptions based on the risk described in the literature and utilisation data. Conclusion This article highlights the methodological challenges and the data required to assess the impact of product-specific safety signals. A structured assessment support tool can be used as a guide for the necessary data elements and steps needed for the measurement or estimation of impact of pharmacovigilance activities on public health, provided that the appropriate data are available.