Retroperitoneal fibrosis and β‐blocking agents: Is there an association?

Aims Retroperitoneal fibrosis (RPF) is a rare chronic fibro‐inflammatory disorder that may be secondary to certain drugs, including β‐blocking agents (BBAs). However, their causative role is unclear. We aimed to investigate this association. Methods Disproportionality analysis was carried out on cases from 1985 to 4 October 2020 in VigiBase, the World Health Organization pharmacovigilance database. The Bayesian‐based IC025 metric and reporting odds ratio were used in order to assess the adverse event signal. We also analysed all published case reports from the literature regarding BBA‐associated RPF to assess the value of suggested supportive clinical evidence. Results In total, 1599 individual case safety reports of RPF were reported to VigiBase, of which 132 (32%) concerned 16 different single BBA. For 12 of these agents (75%), reporting of RPF was disproportionate, indicating a potential safety signal. Line listing analysis of individual case safety reports showed no consistent time interval from start of BBA to RPF diagnosis (range 0.7–264 mo). Dechallenge was negative or unknown in the majority of cases (74%). In 18 published cases from the literature, time from start of BBA to RPF diagnosis varied widely (range 3–156 mo). BBA were discontinued 6 months before (n = 1) or at the time of RPF diagnosis (n = 17). Most patients (84%) also received RPF specific treatment. Follow‐up duration was short (median 5 mo [range 1–24 mo]) and in most cases (83%) relevant follow‐up data were lacking. Conclusion Although disproportionality analysis indicated a potential safety signal for RPF associated with BBAs, clinical evidence did not support a cause‐and‐effect relationship.