The temporal association between adverse drug reactions and antirheumatic drugs utilisation in Western Australia: a retrospective study from real-world data (1995-2015)

BACKGROUND/OBJECTIVES: Adverse drug reactions (ADRs) can result in morbidity, mortality, and higher healthcare costs. Given the limited information available on ADRs associated with antirheumatic medications, this study aims to analyse and compare ADR reporting for these drugs in the pharmacovigilance datasets of Western Australia (WA) and the United States (US).

METHODS: Therapeutic Goods Administration provided WA pharmacovigilance data of selected antirheumatic drugs to from 1995 to 2015. The proportional reporting ratio (PRR) for WA case reports was compared to corresponding USA pharmacovigilance data by assessing the disproportionality of each ADR. clinically significant or true ADRs were determined using the Evans 2001 criteria (n > 2, chi-square > 4, PRR > 2).

RESULTS: A total of 232 reports were found in WA, mostly on sixty-nine women aged 45 to 69. Methotrexate, leflunomide, azathioprine, sulfasalazine, and infliximab had the highest reported ADRs, related to gastrointestinal disorders. Patients who used biological agents in WA had 2.7 times the likelihood of reporting true ADRs compared to conventional antirheumatic drugs. The ADR rates in the two datasets were comparable over the study period.

CONCLUSIONS: The PRR values of ADRs were consistent between WA and US databases. Methotrexate and infliximab use were commonly associated with ADR reports in WA females, with incidence rates comparable to the US; while patients using biological agents were more likely to report true ADRs than those on conventional antirheumatic drugs in WA.