Varying association of extended hours dialysis with quality of life

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, 20.02 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.