Predictors of Health Deterioration Among Older New Zealanders Undergoing Dialysis: A Three-Year Accelerated Longitudinal Cohort Study

Background: Patient involvement in dialysis decision-making is crucial, yet little is known about patient-reported outcomes over time on dialysis. Objective: To examine health-related outcomes over 24 and 36 months in an older cohort of dialysis patients. Design: The "Dialysis outcomes in those aged >= 65 years study" is a prospective longitudinal cohort study of New Zealanders with kidney failure. Setting: Three New Zealand nephrology units. Patients: Kidney failure (dialysis and predialysis) patients aged 65 or above. We have previously described outcomes after 12 months of dialysis therapy relative to baseline. Measurements: Patient-reported social and health factors using the SF-36, EQ-5D, and Kidney Symptom Score questionnaires. Methods: This article describes and compares characteristics of 120 older kidney failure patients according to whether they report "Same/better" or "Worse" health 24 and 36 months later, and identifies predictors of "worse health." Modified Poisson regression modeling estimated relative risks (RR) of worse health. Results: Of 120 patients at 12 months, 47.5% had worse health or had died by 24 months. Of those surviving at 24 months (n = 80), 40% had "Worse health" or had died at 36 months. Variables independently associated with reduced risk of "Worse health" (24 months) were as follows: Maori ethnicity (RR = 0.44; 95% CI = 0.26-0.75), Pacific ethnicity (RR = 0.39; 95% CI = 0.33-0.46); greater social satisfaction (RR = 0.57; 95% CI = 0.46-0.7). Variables associated with an increased risk of "Worse health" were as follows: problems with usual activities (RR = 1.32; 95% CI = 1.04-1.37); pain or discomfort (RR = 1.48; 95% CI = 1.34, 1.63). At 36 months, lack of sense of community (RR = 1.41; 95% CI = 1.18-1.69), 2 or more comorbidities (RR = 1.21; 95% CI = 1.13-1.29), and problems with poor health (RR = 1.47; 95% CI = 1.41-1.54) were associated with "Worse health." Limitations: Participant numbers restricted the number of variables able to be included in the multivariable model, and hence there may have been insufficient power to detect certain associations. Conclusions: In this study, the majority of older dialyzing patients report "Same/better health" at 24 and 36 months. Maori and Pacific people report better outcomes on dialysis. Social and/or clinical interventions aimed at improving social satisfaction, sense of community, and help with usual activities may impact favorably on the experiences for older dialysis patients.