Hecking M, et al. - In this retrospective cohort study, researchers examined the link and prognostic importance between two clinically distinct, bioimpedance spectroscopy (BIS)-derived measures: pre-dialysis and post-dialysis fluid overload (FOpre and FOpost) vs interdialytic weight gain (IDWG). They collected and analyzed data from 38,614 incident patients with ≥ 1 BIS measurement within 90 days of hemodialysis initiation. They found FOpre and FOpost to be consistently positive risk factors for mortality. In addition, low IDGW was found to be associated with short-term mortality, indicating a potential effect of protein-energy wasting. FOpost was found to be the most intuitive fluid marker in clinical practice and may offer the best guidance for volume management in hemodialysis patients as FOpost was found to reflect the volume status without IDWG.