Association between amiodarone use and risk of cataract: a population-based active-comparator study

Background Despite previous concerns about ocular side effects related to amiodarone, the relationship between amiodarone and cataract remains uncertain. Therefore, this study aimed to assess the potential association between amiodarone use and the subsequent risk of cataract, taking into account potential confounders.Methods This population-based, active comparator-controlled cohort study utilized the data from the Taiwan National Health Insurance program and involved adults over 40 years old between 2001 and 2013. We analyzed 12 055 new amiodarone users and contrasted them with a propafenone user cohort. The primary outcome was the incidence of cataract. Inverse-probability treatment-weighting (IPTW) was further used to eliminate the potential confounding effects, and Cox proportional-hazard regression analyses were performed to calculate the risk of cataract. Serial subgroup analyses were also performed.Results In the main analysis, amiodarone users did not exhibit a significant causal relationship in both full cohort [adjusted hazard ratio (aHR): 0.994, 95% confidence interval (CI): 0.913-1.082] and IPTW cohort (IPTW-aHR 0.977, 95% CI: 0.900-1.060). Furthermore, it is important to highlight a significantly reduced risk of cataract among patients with heart failure (IPTW-aHR 0.708, 95% CI: 0.554-0.905) and during the 2-year follow-up period (IPTW-aHR 0.889, 95% CI: 0.794-0.996), implying potential advantages linked to the use of amiodarone.Conclusions The study found no increased risk of cataract with amiodarone, one of the most frequently used antiarrhythmic medications, compared to the use of propafenone. Future research is recommended to explore potential mechanisms and their implications for clinical practice. What is already known on this topic Although numerous case reports suggest a potential association between amiodarone and various ophthalmic conditions, no study has directly examined the link between amiodarone and cataracts while considering potential confounders. What this study adds In this population-based, active-comparator study, amiodarone did not raise the incidence of cataract events compared to propafenone users, even after adjusting for several confounding factors. Importantly, this study observed a reduced risk of cataract among patients with heart failure and during the 2-year follow-up period. How this study might affect research, practice or policy This study could provide crucial clinical information for the safe use of amiodarone in arrhythmia patients and highlight the safe issue for ophthalmologists. Future research is suggested to investigate potential mechanisms and their clinical implications.