Comparison of Measured and Estimated GFR for Rivaroxaban Dosing in Hospitalized Older Adults

Lyu et al. evaluated discrepancies between different glomerular filtration rate (GFR) estimating equations among 30,261 patients with atrial fibrillation 1 Lyu B, Xu Y, Inker LA, et al. Discordance in GFR Estimating Equations and Dosing Guidance by Body Mass Index and Age. Am J Kidney Dis. Published online April 6, 2023. doi:10.1053/j.ajkd.2023.01.453 Google Scholar . In patients with low body mass index (BMI), they observed that GFR was lowest according to estimated creatinine clearance (eCrCl), highest according to estimated GFR (eGFR) indexed to body surface area (BSA), and intermediate according to non-indexed eGFR. In patients with high BMI, they observed the opposite trend. However, this conclusion is a mathematical consequence of the equations themselves and does not require any analysis of patient data 2 Buchkremer F. Segerer S. Estimating glomerular filtration rate: a systematic comparison of the new European Kidney Function Consortium equation with the Chronic Kidney Disease Epidemiology Collaboration equation. Clin Kidney J. 2020; 14: 448-450https://doi.org/10.1093/ckj/sfaa264 Crossref Scopus (5) Google Scholar . In Reply to “Comparison of Measured and Estimated GFR for Rivaroxaban Dosing in Hospitalized Older Adults”American Journal of Kidney DiseasesPreviewWe thank Iversen et al. for their commentary on our article.1 Kidney function is a critical consideration for drug development, approval, and use as it alters pharmacokinetics and pharmacodynamics. Glomerular filtration rate (GFR), the best overall index of kidney function, is complicated to measure directly. Thus, GFR is estimated in most settings. Different methods to estimate GFR are used in drug development and clinical practice. Such inconsistencies may result in confusion and discordance in drug dosing. Full-Text PDF