Analysis of factors predicting mortality of new patients commencing renal replacement therapy 10 years of follow-up

Abstract

Background: The natural history of patients commencing dialysis in East Yorkshire is not well characterised and there is little convincing evidence which has studied the impact of potential factors prior to commencement of renal replacement therapy (RRT) at predicting mortality during dialysis. The aim of this study was to examine the previously published 5-year data on end stage renal disease and co-morbid risk factors for mortality at 10 years.

Methods: An observational cohort study of subjects commencing dialysis in 2001/02 in East Yorkshire with a mean follow up from dialysis initiation of 8.8 years. Predictors of mortality were determined by univariate, multivariate analysis and survival via Kaplan-Meier analysis. Assessment of the utility of the Tangri risk calculator was carried out in addition to slope change in eGFR prior to dialysis commencement.

Results: Baseline characteristics and the preferred mode of dialysis remained concordant with the original trial. The mortality rate at the end of the study period was 60% (56/94) with 30% (29) of patients having been transplanted. Highlighted in the 5 year data a significant proportion of mortality was made up of vascular disease and sepsis (71%) but this proportion had decreased (57%) by 10 years. Cardiac disease was the commonest cause of death but notably in 18% of patients, death was related to dialysis or withdrawal of treatment. Vascular disease and diabetes remained independent risk factors and predicative of mortality. Calcium-phosphate product which was associated in the early years with mortality was not in later years. Use of the risk calculator was predictive of commencement of RRT but not mortality but slope change in eGFR was predictive of mortality.

Conclusions: Although diabetes and vascular disease remained predictive of mortality, interestingly calcium-phosphate levels are no longer significant and may be a more specific predictor of early cardiac mortality. Slope eGFR changes prior to RRT are a predictor of mortality. We speculate that aggressive management of cardiac risk factors in addition to early transplantation may be key to influencing the impact of survival in this cohort in addition to possible measures to delay renal progression.

Figure 1

Kaplain-Meier survival curves over 10 years for main risk factors. (A) Vascular disease versus no vascular disease; (B) Diabetes versus no diabetes; (C) Calcium phosphate product quartiles.

Figure 2

Kaplan-Meier Survival curves for predicting the mortality of those with severe slope eGFR deterioration (highest quartile – lower line) prior to commencement of dialysis compared to the lower 3 quartiles of rate of eGFR progression (upper line).