Optimizing the Measurement of Dialysis: Which Denominator?

[摘要] Comparisons of outcomes in men versus women undergoing chronic maintenance hemodialysis have shown differences usually favoring men despite larger doses given to women (1–3). All agree that larger doses are given to women because of their smaller size, which allows delivery of more dialysis within a short time frame. When the prescribed dose is adjusted to body size, providing “equal” doses for men and women, the outcome in women is often worse, suggesting underdialysis (4). In the Hemodiaysis (HEMO) Study, increasing the dose in women appeared to improve survival and other outcomes but attempts to link the improved survival to their smaller size, measured in several ways, were unsuccessful although the investigators acknowledged that separating sex and size was difficult (5). The investigators concluded tentatively that sex in some unknown way was responsible for the improved response to the higher dose (5). Still championing the idea that size was responsible, Daugirdas et al. showed that substitution of surface area (SA) in place of V in the dose expression Kt/V might explain the HEMO Study findings (6). They developed a method for converting standard Kt/V to a SA normalized dose (SAN-stdKt/V), allowing continued application of currently accepted guidelines for dialysis dosing (7). After normalizing by SA, they showed that women randomized to the higher dose in the HEMO Study actually received a dose that was equal to the lower dose given to the men (see Figure 1 below) (6). To test the validity of the SA modified dose expression, Ramirez and colleagues recently reported outcomes in a larger cohort of 7229 Centers for Medicare and Medicaid Services (CMS) patients (3).

[学科分类] 泌尿医学

[关键词] Bone marrow necrosis;Sickle cell disease;Hyperhemolysis syndrome