Cohort Study: Ondansetron Initiation Linked to Increased 10-Day Sudden Cardiac Death Risk in Hemodialysis Patients
20 Oct, 2024 | 14:05h | UTCBackground: Individuals undergoing maintenance hemodialysis have a markedly elevated risk of sudden cardiac death, attributed to structural heart disease, electrolyte imbalances, and polypharmacy. Ondansetron, a commonly used antiemetic known to prolong the QT interval, has been associated with fatal arrhythmias when administered intravenously in the general population. However, its cardiac safety profile in the hemodialysis population remains unclear.
Objective: To assess whether initiation of oral ondansetron, compared to antiemetics with lesser QT-prolonging potential, is associated with a higher 10-day risk of sudden cardiac death among patients receiving maintenance hemodialysis.
Methods: This new-user, active-comparator cohort study analyzed data from the United States Renal Data System between 2012 and 2019. A total of 119,254 patients receiving in-center hemodialysis who initiated either oral ondansetron or comparator antiemetics (promethazine, metoclopramide, or prochlorperazine) were included. Inverse probability of treatment-weighted survival models estimated adjusted hazard ratios (aHR) and risk differences (aRD), using an intention-to-treat approach with non-sudden cardiac death as a competing event.
Results: Among the patients, 64,978 (55%) initiated ondansetron, while 54,276 (45%) initiated comparator antiemetics. Ondansetron initiation was associated with a higher 10-day risk of sudden cardiac death compared to comparator drugs (aHR 1.44; 95% CI, 1.08–1.93; aRD 0.06%; 95% CI, 0.01%–0.11%). The number needed to harm was 1,688. Secondary analyses of additional cardiac outcomes, including ventricular arrhythmias and cardiovascular mortality, yielded consistent findings.
Conclusions: Initiation of oral ondansetron is associated with an increased short-term risk of sudden cardiac death among patients on maintenance hemodialysis compared to initiation of antiemetics with lesser QT-prolonging potential.
Implications for Practice: Clinicians should exercise caution when prescribing ondansetron to hemodialysis patients and consider alternative antiemetics with lower QT-prolonging risks. If ondansetron is necessary, monitoring for cardiac arrhythmias and performing electrocardiograms may be advisable to mitigate potential risks.
Study Strengths and Limitations: Strengths include a large, nationally representative cohort and an active-comparator design that minimizes confounding. Limitations involve potential residual confounding inherent in observational studies, possible misclassification of outcomes, and inability to assess dose-response relationships due to power constraints.
Future Research: Further studies are warranted to confirm these findings, elucidate the underlying mechanisms of increased cardiac risk, and evaluate the safety of ondansetron across different dosages and patient subgroups within the hemodialysis population.