Health-Related Quality of Life and Disability Among Older New Zealanders With Kidney Failure: A Prospective Study

BACKGROUND: Disability is prevalent in individuals with kidney failure and can contribute to significantly reduced quality of life and survival. In older individuals with kidney failure, disability can be caused by a combination of factors, including issues directly related to their kidney disease and/or treatment, including weakness, low energy, and low activity. Few studies have investigated health-related quality of life (HRQoL) as a possible predictor of disability among older individuals experiencing kidney failure. OBJECTIVE: This study aimed to determine if patient-reported HRQoL, and/or other factors at baseline, predicts disability in people with kidney failure, aged ≥65 years, after 12 months of follow-up. DESIGN: The DOS65+ study was an accelerated longitudinal cohort design comprising of both cross-sectional and longitudinal components. Participants were eligible if they were aged ≥65 years, had chronic kidney disease stage 5G (CKD 5G) (estimated glomerular filtration rate (eGFR) <15 ml/min/1.73 m(2)), and had: commenced kidney replacement education, or were on an active conservative pathway, or were newly incident dialysis patients commencing dialysis therapy or prevalent on dialysis. SETTING: Three New Zealand District Health Board (DHB) nephrology units (Counties Manukau, Hawke’s Bay, and Southern DHB) were involved in the study. PARTICIPANTS: Participants were eligible if they were aged ≥65 years, had CKD 5G (eGFR <15 ml/min/1.73 m(2)), and had: commenced kidney replacement education, or were on an active conservative pathway, or were newly incident dialysis patients commencing dialysis therapy or prevalent on dialysis. MEASUREMENTS: Disability and HRQoL were measured by EQ-5D-3L, a WHO Disability Assessment Schedule (WHODAS) 2.0. METHODS: Baseline and 12-month data from our longitudinal dialysis outcomes in older New Zealanders’ study were analyzed to determine if HRQoL at baseline predicted disability outcomes 12 months later. RESULTS: Of the 223 participants at baseline, 157 participants completed a follow-up interview 12 months later. Individuals with “considerable disability” at baseline had a significantly (86%) higher risk of experiencing “considerable disability” at 12 months compared with those with “lesser/no disability” at baseline. Two thirds of those with ≥3 comorbidities were experiencing “considerable disability.” In addition, those with problems with EQ-5D-3L self-care, EQ-5D-3L usual activities, and EQ-5D-3L anxiety/depression reported higher rates of disability. LIMITATIONS: Selection bias is likely to have been an issue in this study as participants were excluded from the follow-up interview if they had an intercurrent illness requiring hospitalization within 2 weeks of the survey interview or if the treating nephrologist judged that the individual’s ability to take part was significantly impaired. Sample size meant there were a limited number of explanatory/confounding variables that could be investigated in the multivariable model. CONCLUSIONS: EQ-5D-3L mobility and self-care may be useful in predicting subsequent disability for individuals with CKD 5G. Although individuals with kidney failure often experience disability, previous studies have not clearly identified HRQoL or disability as predictors of later disability for individuals with kidney failure. Therefore, we would recommend the assessment of mobility and self-care, in conjunction with existing disabilities in the clinical review and pre-dialysis education of individuals with kidney failure as they approach the need for kidney replacement therapy. Trial registration: the Australian and New Zealand clinical trials registry: ACTRN12611000024943.