Individualizing kt by sex and body surface area: implications for survival in hemodialysis patients

Background The administration of an adequate dialysis dose is a critical aspect for ensuring the effectiveness of hemodialysis (HD) treatment and improving survival. Kt is a key indicator to evaluate the dose, with two targets: based on sex (Kt-Sx) and body surface area (Kt-BSA). Methods This retrospective study (2022–2023) conducted across 15 centers HD analyzed 1 829 prevalent patients and 317 842 HD sessions. Results It was found that 65.9% met both Kt targets, 21.2% met only Kt-Sx, and 12.9% met neither. Failure to meet both of the targets was associated with being male, older age, shorter time on HD, higher comorbidity, low BMI, use of a catheter, shorter sessions, conventional HD, low flow rates, and small membranes. Meeting at least the Kt-Sx target was associated with a 41.6% reduction in 24-month mortality risk, and an even more favorable association was observed when both targets were met, reducing the risk by 61.7%. Conclusions These findings highlight the importance of personalizing dialysis considering both sex and body surface area, particularly in overweight or obese patients, to improve survival.