Effects of Kt/Vurea on outcomes according to age in patients on maintenance hemodialysis

The guidelines recommended target and minimum single-pool Kt/Vurea are 1.4 and 1.2, respectively, in hemodialysis patients. However, the optimal hemodialysis dose remains controversial. We investigated the effects of Kt/Vurea on patient outcomes according to age, with a focus on older patients. This study used the hemodialysis quality assessment program and claims datasets. Patients were divided into four subgroups according to age (<65, 65-74, 75-84, and ≥85 years). Each group was divided into three subgroups according to Kt/Vurea : reference (ref) (1.2 ≤ Kt/Vurea ≤ 1.4), low (< 1.2), and high (> 1.4). The low, ref, and high Kt/Vurea groups included 1668, 8156, and 16 546 (< 65 years); 474, 3058, and 7646 (65-74 years); 225, 1362, and 4194 (75-84 years); and 14, 126, and 455 (≥85 years) patients, respectively. The low Kt/Vurea group had higher mortality rates than the ref Kt/Vurea group irrespective of age [adjusted hazard ratio (aHR), 95% confidence interval (CI): 1.23, 1.11-1.36; 1.14, 1.00-1.30; 1.28, 1.09-1.52; and 2.10, 1.16-3.98, in patients aged <65, 65-74, 75-84, and ≥85 years, respectively]. The high Kt/Vurea group had lower mortality rates than the ref Kt/Vurea group in patients aged <65 and 65-74 years (aHR, 95% Cl: 0.87, 0.82-0.92 and 0.93, 0.87-0.99 in patients aged <65 and 65-74 years, respectively). These results support the current recommendations of a minimum Kt/Vurea of 1.2 even in patients age ≥85 years. In young patients, Kt/Vurea above the recommended threshold can be beneficial for survival.