B SMYTH1,2, K HOWARD1, L ZUO3, J DE ZOYSA4,5, C CHAN6, N GRAY7,8, A CASS9, M GALLAGHER2,10,11, V PERKOVIC2, M JARDINE2,11
1Sydney School of Public Health, University of Sydney, Sydney, Australia, 2The George Institute for Global Health, UNSW, Sydney, Australia, 3Peking University People’s Hospital, Beijing, China, 4North Shore Hospital, Auckland, New Zealand, 5Department of Medicine, University of Auckland, Auckland, New Zealand, 6University Health Network, Toronto, Canada, 7Sunshine Coast University Hospital, Birtinya, Australia, 8Sunshine Coast Clinical School, University of Queensland, , Australia, 9Menzies School of Health Research, Charles Darwin University, Darwin, Australia, 10Sydney Medical School, University of Sydney, Sydney, Australia, 11Renal Unit, Concord Repatriation General Hospital, Sydney, Australia
Aim: To estimate the effect of extended hours dialysis on utility-based quality of life (QOL) using two distinct multi-attribute utility instruments.
Background: Health economic evaluations often rely on measurements of health utility. Validated health utility assessment tools are available but whether they perform similarly is rarely assessed.
Methods: The ACTIVE Dialysis trial randomised 200 participants to extended hours (≥24 hours/week) or standard hours (≤18 hours/week) haemodialysis for 12 months. Utility-based QOL was assessed every three months by the EuroQOL-5 Dimensions (EQ-5D) and Short Form-6 Dimensions (SF-6D). The mean difference in utility weights between groups was obtained by mixed linear regression. Quality adjusted life years (QALYs), a measure that combines survival and quality of life, were calculated.
Results: Extended dialysis hours did not improve utility-based QOL measured by the EQ-5D (0.036 [95%CI -0.022, 0.093]; p=0.223) but did significantly improve it when measured by the SF-6D (0.027 [95%CI 0.003, 0.052]; p=0.026). There was no significant difference in mean QALYs gained per patient from extended over standard dialysis as measured by the SF-6D (0.015 [95%CI -0.070, 0.041]) or the EQ-5D (0.029 [95%CI -0.108, 0.049]) – equivalent to a mean per patient gain of 5.5 (95%CI -25.6, 15.0) and 10.6 (95%CI -39.4, 17.9) days of perfect health, respectively.
Conclusions: The EQ-5D and SF-6D resulted in different interpretations of utility-based QOL effects of extended hours dialysis, although the significant improvement in utility-based QOL found with the SF-6D did not translate into a significant gain in QALYs. These results emphasise the need for a better understanding of the impact of different scoring algorithms and instrument properties on the performance of multi-attribute utility instruments to measure QOL in dialysis patients.
Dr Smyth is a nephrologist and PhD candidate at The George Institute for Global Health. His research interests include dialysis, especially randomised controlled trial methodology and evidence as well as patient reported outcomes in dialysis patients.