Association between potential supplement-drug interactions and liver diseases in patients with cancer: A large prospective cohort study.

Background & Aims: The concurrent use of herbal and dietary supplements and conventional drugs can lead to interactions in patients with cancer, of which hepatotoxicity is one of the most concerning sequelae. This study examined the potential supplement-drug interactions involving the hepatic system, and their associations with documented liver diseases, among patients with cancer in a large population-based cohort in the UK Biobank.

Methods: Participants diagnosed with cancer and had completed supplement-use assessment after diagnosis were included. Potentially interacting supplement-drug combinations that involved CYP enzymes or increased the risk of hepatotoxicity were identified from four tertiary databases. Liver diseases were identified using ICD-codes K70-77. Log-binomial regression was used to investigate the associations between potentially-interacting supplement-drug combinations and liver diseases documented (1) at any time, and (2) confined to only after the time of supplement-use assessment, adjusting for age, sex and pre-existing comorbidities.

Results: This analysis included 30,239 participants (mean age = 60.0 years; 61.9% female). Over half (n = 17,698, 58.5%) reported the use of supplements after cancer diagnoses. Among supplements users, 36.9% (n = 6537/17,698) were on supplement-drug combinations with interacting potential involving the hepatic system. Patients taking supplements and drugs who had hepatic comorbidities were more likely to take potentially interacting pairs (adjusted risk ratio = 1.14, 95% CI = 1.06-1.23, p < 0.001). However, no significant association was observed between the use of these combinations and subsequent liver diseases (all p > 0.05).

Conclusion: Approximately one-third of the participants who had cancer and were supplement users had a risk of potential supplement-drug interactions that contribute to adverse liver effect. Healthcare professionals should communicate with patients with cancer, especially those with pre-existing liver diseases, about supplement use and proactively assess the clinical significance of potential interactions.