Association Between Concomitant Use of Hydrochlorothiazide and Adverse Chemotherapy-Related Events among Older Women with Breast Cancer Treated with Cyclophosphamide
A partir des données des registres américains des cancers portant sur des patientes âgées de plus de 66 ans et atteintes d'un cancer du sein diagnostiqué entre 2007 et 2011, cette étude analyse l'association entre une utilisation d'hydrochlorothiazide (un diurétique thiazidique) et la survenue d'effets indésirables induits par une chimiothérapie adjuvante à base de cyclophosphamide (hospitalisation pour une neutropénie et arrêt du traitement anticancéreux)
Résumé en anglais
Background: The pharmacy reference database, Micromedex, lists concomitant hydrochlorothiazide and cyclophosphamide use as a potential, major drug–drug interaction (DDI), although only one small, single-center study supports this claim. Our objective was to estimate associations between this potential DDI and two adverse chemotherapy-related events, neutropenia-related hospitalizations and treatment regimen discontinuation, among a cohort of women with breast cancer initiating adjuvant chemotherapy containing cyclophosphamide.
Methods: Using linked Surveillance, Epidemiology, and End Results Program (SEER)-Medicare data, we included women 66 years and older with breast cancer diagnosis between 2007 and 2011, who initiated a regimen containing cyclophosphamide. Risk ratios (RR) and 95% confidence intervals for adverse outcomes comparing women exposed versus unexposed to the potential DDI were assessed using modified multivariable Poisson regression adjusting for potential confounders.
Results: In total, 27% of women receiving cyclophosphamide treatment were exposed to concomitant hydrochlorothiazide, of which 11% experienced a neutropenia-related hospitalization and 21% discontinued their chemotherapy regimen prior to completion. Adjusted risks of both adverse events were similar between those exposed and unexposed to the potential DDI [neutropenia-related hospitalization: adjusted RR (aRR) = 0.92 (0.70–1.21); treatment discontinuation: aRR = 1.00 (0.96–1.05)].
Conclusions: Our results do not support an association between concomitant hydrochlorothiazide use and two clinically relevant adverse chemotherapy-related events.
Impact: Our results support reassessing and potentially lowering severity of this potential interaction in drug reference databases.
