High-performance dialyzers and mortality in maintenance hemodialysis patients

Abstract

Few data are available regarding the association of dialyzer type with prognosis. In Japan, dialyzers are classified as types I, II, III, IV, and V based on β₂-microglobulin clearance rates of < 10, < 30, < 50, < 70, and ≥ 70 mL/min, respectively. We investigated the relationship of the 5 dialyzer types with 1-year mortality. This nationwide cohort study used data collected at the end of 2008 and 2009 by the Japanese Society for Dialysis Therapy Renal Data Registry. We enrolled 203,008 patients on maintenance hemodialysis who underwent hemodialysis for at least 1 year and were managed with any of the 5 dialyzer types. To evaluate the association of dialyzer type with 1-year all-cause mortality, Cox proportional hazards models and propensity score-matched analyses were performed. After adjustment of the data with clinicodemographic factors, the type I, II, and III groups showed significantly higher hazard ratios (HRs) than the type IV dialyzers (reference). After adjustment for Kt/V and β₂-microglobulin levels, the HRs were significantly higher in the type I and II groups. After further adjustment for nutrition- and inflammation-related factors, the HRs were not significantly different between the type IV and type I and II groups. However, type V dialyzers consistently showed a significantly lower HR. With propensity score matching, the HR for the type V dialyzer group was significantly lower than that for the type IV dialyzer group. Additional long-term trials are required to determine whether type V dialyzers, which are high-performance dialyzers, can improve prognosis.

Figure 1

Flowchart of study participants. β2MG β2-microglobulin, CVD cardiovascular disease.

Figure 2

Hazard ratios of all-cause mortality for dialyzer type in 203,008 hemodialysis patients using a standard Cox proportional hazards regression. Bars with no fill are adjusted with clinicodemographic factors including age, sex, dialysis vintage, primary causes of end-stage kidney disease, and cardiovascular complication presence/absence. Gray-filled bars are adjusted with dialysis dose as assessed by Kt/V and β₂-microglobulin levels in addition to clinicodemographic factors. Dark gray-filled bars are adjusted with clinicodemographic factors, dialysis dose, and nutrition- and inflammation-related factors, including body mass index, hemoglobin, C-reactive protein, and serum albumin levels, normalized protein catabolic rate, and simplified creatinine index. *P < 0.05, **P < 0.01, and ***P < 0.0001 versus the type IV dialyzer group. Error bars correspond to 95% confidence intervals.

Figure 3

Hazard ratios of all-cause mortality for the 4 dialyzer groups versus the type IV dialyzer group after propensity score matching using a Cox proportional hazards regression. *P < 0.05 versus the type IV dialyzer group. Error bars correspond to 95% confidence intervals.