Age may explain the association of an early dialysis initiation with poor survival.
BACKGROUND
Some studies postulate that early dialysis initiation may increase mortality.


OBJECTIVE
The aim of the present study was to assess to what extent this was due to confounding by age.


METHODS
Observational retrospective cohort study.


METHODS
We studied all patients starting dialysis therapy between 1 January 1995 and 31 December 2009 in our center. The following variables at dialysis initiation in end-stage renal disease (ESRD) patients were analysed: estimated glomerular filtration rate (eGFR), age, gender, diabetes mellitus, serum albumin, hemoglobin, period of dialysis initiation, history of ischemic heart disease and stroke. Multivariate Cox model was used to calculate adjusted patient survival.


RESULTS
Over the last 15 years, 428 patients initiated dialysis therapy in our reference area. Median eGFR at dialysis initiation was 8.16 ml/min. In the univariate analysis, increased eGFR, age, dialysis initiation 1995-1999/2000-2004, diabetes and history of ischemic heart disease were associated (P < 0.05) with increased mortality in ESRD. Patients that started dialysis program with eGFR > 8.16 were older than those who did it with eGFR < 8.16 (66 vs. 61 years, P < 0.001). The association between mortality and eGFR in the crude multivarite Cox model was lost when the model was adjusted by age. In the multivariate Cox model, dialysis initiation period, serum albumin and history of ischemic heart disease were associated with mortality.


CONCLUSIONS
History of ischemic heart disease, serum albumin and dialysis start before 2005 were risk factors for mortality in ESRD patients. Older age is usually associated with early dialysis initiation, so age adjustment is needed to perform studies aimed to calculate the effect of eGFR at dialysis initiation on survival.
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain msoler@parcdesalutmar.cat.
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MJ
Soler
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Montero
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
M J
MJ
Pascual
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Barrios
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Márquez
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Orfila
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Cao
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Arcos
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Collado
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Comas
From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain From the Department of Nephrology, Hospital del Mar, Barcelona, Spain, Institut Hospital del Mar of Medical Research (IMIM), Barcelona, Spain and Catalan Renal Registry, Catalan Transplant Organization, Health Department, Generalitat of Catalonia, Barcelona, Spain.
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Pascual
D000367:Age Factors; D000368:Aged; D004812:Epidemiologic Methods; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D006435:Renal Dialysis / Q000401:mortality*