Limitations
It is noteworthy that VigiBase collects data on individual case safety reports and does not contain information on PDE5i consumers who have not exhibited any adverse events (i.e., controls). Thus, the case-non-case approach does not estimate the risk of occurrence of a specific ADR, unlike case-control studies, and alternatively investigates the risk of ADR reporting through ROR. Data in VigiBase are heterogeneous and gathered from various sources, including healthcare professionals, pharmaceutical companies, and patients. Consequently, data is subjected to reporting bias, and the probability that the suspected adverse event is drug-related is not the same in all cases. Additionally, incomplete and unreliable dosing data imposes a significant limitation on our study, preventing us from performing a dose-response analysis and investigating whether the occurrence of an ADR in a particular subpopulation is a consequence of over-dose. Lastly, VigiBase, by nature, does not provide any information on patients’ comorbidity, which may predispose one to a specific ADR. Accordingly, certain causal drug-ADR associations cannot be drawn.