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

Abstract

Abstract Background 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. Methods 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). Results The low, ref, and high Kt/Vurea groups included 1,668, 8,156, and 16,546 (< 65 years); 474, 3,058, and 7,646 (65–74 years); 225, 1,362, and 4,194 (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). Conclusions 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.