Abstract
Background
Chronic Kidney Disease (CKD) has been characterised into five stages with CKD5 defined as an estimated glomerular filtration rate (eGFR) of < 15ml/min/1.73m2 and includes those receiving renal replacement therapy (RRT) (dialysis and transplantation) or those who are eligible for RRT but are not receiving treatment. In New Zealand (NZ) approximately 1000 individuals commence dialysis each year, with the majority aged between 65-74 years. Māori experience a two-fold higher rate of CKD5 compared to non-Māori. CKD5 has a potential to have a negative effect on an individual’s health-related quality of life (HRQoL). CKD5 is associated with disability. Little research has been completed to understand the impact of HRQoL on disability in people aged ≥65 years with CKD5.
Aims
The aims of the Health and Disability Study (H&D Study) presented in this thesis are to describe cross-sectional associations between HRQoL and disability among a cohort of older New Zealanders with CKD5, and to determine which factors at recruitment, including HRQoL, have the potential predict disability outcomes 12 months later; and to describe the HRQoL and disability outcomes for an older Māori cohort with CKD5.
Methods
A rapid review was completed to identify important models of HRQoL and disability, with a scoping review completed to identify existing research investigating HRQoL and disability in CKD patients. The dialysis outcomes in those aged ≥65 study (DOS65+ Study) was an “accelerated longitudinal” cohort which aimed to determine the HRQoL of those aged ≥65 years with CKD5, to aid in developing evidence-based guidelines for the management of CKD5 in older adults. This study analysed the baseline characteristics of the 225 participants in the DOS65+ Study to determine associations between HRQoL (EQ-5D-3L) and disability (WHODAS 2.0). Participants who were followed to 12 months (n=156) were analysed using modified Poisson regression with robust standard errors to identify which factors at recruitment, including HRQoL, predict disability outcomes 12 months later. Descriptive analyses were used to describe the Māori cohort (n=49) and their outcomes.
Results
Of the 223 participants analysed at baseline, those with 3 or more comorbidities were more likely to be disabled as were those with moderate-severe problems with the EQ-5D-3L dimensions of mobility, self-care, usual activities and anxiety/depression. The multivariable analyses indicate that those disabled at baseline were at an 86% higher risk of being disabled at 12 months. The HRQoL dimensions of self-care and mobility at baseline predicted disability at 12 months by 31% and 38% respectively. Dialysis vintage of ≥2 years was associated with lower disability. Within the Māori cohort, HRQoL and disability at baseline appear important in predicting disability at 12 months, however this result is limited due to small sample size.
Discussion and Conclusion
Issues with EQ-5D-3L mobility, self-care and disability at baseline predict disability at 12 months in this cohort. The EQ-5D-3L and WHODAS 2.0 allow for patients to determine how they perceive their HRQoL and disability which may be important in improving patients’ clinical experiences and therefore outcomes. Patient participation in assessing these HRQoL components and baseline disability could help with CKD5 education and planning for RRT.