Varying Association of Extended Hours Dialysis with Quality of Life

Abstract

Background and objectives: Little is known about the effect of changes in dialysis hours on patient-reported outcome measures. We report the effect of doubling dialysis hours on a range of patient-reported outcome measures in a randomized trial, overall and separately for important subgroups.

Design, setting, participants, & measurements: The A Clinical Trial of IntensiVE Dialysis trial randomized 200 participants to extended or standard weekly hours hemodialysis for 12 months. Patient-reported outcome measures included two health utility scores (EuroQOL-5 Dimensions-3 Level, Short Form-6 Dimension) and their derived quality-adjusted life year estimates, two generic health scores (Short Form-36 Physical Component Summary, Mental Component Summary), and a disease-specific score (Kidney Disease Component Score). Outcomes were assessed as the mean difference from baseline using linear mixed effects models adjusted for time point and baseline score, with interaction terms added for subgroup analyses. Prespecified subgroups were dialysis location (home- versus institution-based), dialysis vintage (≤6 months versus >6 months), region (China versus Australia, New Zealand, Canada), and baseline score (lowest, middle, highest tertile). Multiplicity-adjusted P values (Holm-Bonferroni) were calculated for the main analyses.

Results: Extended dialysis hours was associated with improvement in Short Form-6 Dimension (mean difference, 0.027; 95% confidence interval [95% CI], 0.00 to 0.05; P=0.03) which was not significant after adjustment for multiple comparisons (P_adjusted =0.05). There were no significant differences in EuroQOL-5 Dimensions-3 Level health utility (mean difference, 0.036; 95% CI, -0.02 to 0.09; P=0.2; P_adjusted =0.2) or in quality-adjusted life years. There were small positive differences in generic and disease-specific quality of life: Physical Component Summary (mean difference, 2.3; 95% CI, 0.6 to 4.1; P=0.01; P_adjusted =0.04), Mental Component Summary (mean difference, 2.5; 95% CI, 0.5 to 4.6; P=0.02; P_adjusted =0.05) and Kidney Disease Component Score (mean difference, 3.5; 95% CI, 1.5 to 5.5; P=0.001; P_adjusted =0.005). The results did not differ among predefined subgroups or by baseline score.

Conclusions: The effect of extended hours hemodialysis on patient-reported outcome measures reached statistical significance in some but not all measures. Within each measure the effect was consistent across predefined subgroups. The clinical importance of these differences is unclear.

Keywords: Australia; Canada; China; New Zealand; chronic hemodialysis; confidence intervals; home hemodialysis; humans; kidney; kidney diseases; patient reported outcome measures; quality of life; quality-adjusted life years; randomized controlled trials; renal dialysis.

Graphical abstract

Figure 1.

Mean (95% CIs) health utility over time. (A) EuroQOL-5-Dimension-3 Level (EQ5D), mean difference 0.036; 95% confidence interval, 0.02 to 0.09; P=0.2; P_adjusted=0.2. (B) Short Form-6 Dimension (SF-6D), mean difference 0.027; 95% confidence interval, 0.00 to 0.05; P=0.03; P_adjusted=0.05. Mean scores at each time point are presented in the Supplemental Material.

Figure 2.

Effect of extended hours dialysis on health utility by subgroups. Mean difference between treatment groups from linear mixed effects model of health utility and subgroup, adjusted by time point and baseline score and with an interaction between subgroup and treatment group. Zero represents no effect of the intervention, positive values reflect benefit. Aus, Australia; Can, Canada; NZ, New Zealand; EQ5D, EuroQOL-5 Dimension-3 Level; SF6D, Short-Form 6-Dimension.

Figure 3.

Mean (95% CIs) generic and disease-specific quality of life over time. (A) Physical Component Summary (PCS). Mean difference, 2.3; 95% confidence interval (95% CI), 0.6 to 4.1; P=0.01; P_adjusted=0.04. (B) Mental Component Summary (MCS). Mean difference, 2.5; 95% CI, 0.5 to 4.6; P=0.02; P_adjusted=0.05. (C) Kidney Disease Component Summary (KDCS). Mean difference, 3.5, 95% CI, 1.5 to 5.5; P=0.001; P_adjusted=0.005. Mean scores at each time point are presented in the Supplemental Material.

Figure 4.

Effect of extended hours dialysis on generic and disease-specific quality of life by subgroups. Mean difference between treatment groups from linear mixed effects model of health utility and subgroup, adjusted by time point and baseline score and with an interaction between subgroup and treatment group. Zero represents no effect of the intervention, positive values reflect benefit. Aus, Australia; Can, Canada; PCS, Physical Component Summary; MCS, Mental Component Summary; KDCS, Kidney Disease Component Summary; NZ, New Zealand; SF6D, Short-Form 6-Dimension.

Figure 5.

Standardized effect of extended hours dialysis on quality of life measures. The y-axis represents the effect size defined by the ratio of mean difference to the baseline SD of each quality-of-life score. Effect size categorized as <0.2 not important; 0.2 to <0.5 small, 0.5 to <0.8 moderate; and ≥0.8 large. KDCS, Kidney Disease Component Summary; QOL, quality of life; SF6D, Short-Form 6-Dimension; EQ5D, EuroQOL 5-Dimensions 3-Level; PCS, Physical Component Summary; MCS, Mental Component Summary.

Figure 6.

Mean change in physical and mental quality of life with intensive hemodialysis on physical and mental quality of life: meta-analysis of four trials. Mean difference in short form-36 physical and mental quality of life. MCS, Mental Component Summary; PCS, Physical Component Summary.