Survival of elderly dialysis patients is predicted by both patient and practice characteristics

Abstract

Background: Increasing numbers of elderly patients face decisions about the management of end-stage kidney disease. Improved understanding of contemporary patient and practice factors influencing prognosis may assist decision making for individual patients and their care providers.

Methods: This is a prospective registry study using multivariable proportional hazards models. A total of 1781 patients aged ≥ 75 years at dialysis initiation recorded in ANZDATA, the Australia and New Zealand renal replacement registry, between January 2002 and December 2005. The patient characteristics were demographic and comorbid conditions. The practice characteristics were late referral, access at dialysis initiation and intended dialysis modality (modality established by 90 days). The study outcome was mortality censored at 31 December 2007 or at recovery of renal function (of at least 30 days), transplantation or loss to follow-up.

Results: Median follow-up was 2.3 years (interquartile range 1.1-3.3 years) during which time, 65% of the patients died. Baseline factors independently associated with mortality were older age [hazard ratio (HR) 1.24 for 5-year increase, 95% confidence interval (CI) 1.13-1.36], body mass index <18.5 (HR 1.78, 95% CI 1.33-2.38), number of comorbidities (one comorbidity HR 1.38, 95% CI 1.13-1.69; two comorbidities HR 1.55, 95% CI 1.27-1.89; three or more comorbidities HR 1.89, 95% CI 1.55-2.31), late referral (HR 1.19, 95% CI 1.02-1.39), peritoneal dialysis as intended modality (HR 1.26, 95% CI 1.08-1.47) and unprepared access (HR 1.43, 95% CI 1.23-1.67). The limitations of the study were the observational nature of the analysis, potential selection bias introduced through analysis of a group who actually commenced dialysis and the potential confounding from unmeasured factors or dichotomous reporting of comorbidities.

Conclusions: Within the elderly cohort, other patient characteristics have a greater association with mortality than 5-year age increments. Even after consideration of patient characteristics, practice factors have a striking impact on the survival of elderly patients commencing dialysis. In the absence of randomized studies, efforts to enhance the identification and preparation of elderly patients for dialysis may improve outcomes within current settings.