Fluoroquinolones and the risk of severe hypoglycaemia among sulphonylurea users: Population-based cohort study.

AIM: Fluoroquinolone-related hypoglycaemia is rare but may become clinically relevant in individuals at high baseline hypoglycaemic risk, such as patients with diabetes using sulphonylureas. Our population-based cohort study assessed whether fluoroquinolones are associated with an increased risk of severe hypoglycaemia compared with amoxicillin among patients treated with sulphonylureas.

MATERIALS AND METHODS: Using the UK's Clinical Practice Research Datalink Aurum linked to hospitalization and vital statistics data, we assembled a base cohort of patients who initiated second-generation sulphonylureas (1998-2020). The study cohort included patients initiating either fluoroquinolones or amoxicillin while on sulphonylureas. Using an intent-to-treat exposure definition, we assessed the 30-day risk of severe hypoglycaemia (hospitalization with or death because of hypoglycaemia) associated with fluoroquinolones compared with amoxicillin. Cox models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) of severe hypoglycaemia after 1:5 matching on previous sulphonylurea use and propensity scores. Secondary analyses were stratified by demographics and glycated haemoglobin.

RESULTS: Overall, 143 417 patients initiated fluoroquinolones (n = 13 123) or amoxicillin (n = 130 294) while on sulphonylureas. Compared with amoxicillin, fluoroquinolones were not associated with the risk of severe hypoglycaemia (HR, 1.17; 95% CI, 0.91-1.50). Fluoroquinolones were associated with an increased risk in patients <65 years (HR, 2.90; 95% CI, 1.41-5.97) but not in those ≥65 years (HR, 1.03; 95% CI, 0.79-1.35) in stratified analyses. There was no evidence of effect modification by sex or glycated haemoglobin.

CONCLUSIONS: In patients using second-generation sulphonylureas, fluoroquinolones were not associated with an increased risk of severe hypoglycaemia compared with amoxicillin. An increased risk among younger adults is possible.