Association of residual urine output with mortality, quality of life, and inflammation in incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study.
BACKGROUND
Residual kidney function (RKF) is associated with improved survival in peritoneal dialysis patients, but its role in hemodialysis patients is less well known. Urine output may provide an estimate of RKF. The aim of our study is to determine the association of urine output with mortality, quality of life (QOL), and inflammation in incident hemodialysis patients.


METHODS
Nationally representative prospective cohort study.


METHODS
734 incident hemodialysis participants treated in 81 clinics; enrollment, 1995-1998; follow-up until December 2004.


METHODS
Urine output, defined as producing at least 250 mL (1 cup) of urine daily, ascertained using questionnaires at baseline and year 1.


METHODS
Primary outcomes were all-cause and cardiovascular mortality, analyzed using Cox regression adjusted for demographic, clinical, and treatment characteristics. Secondary outcomes were QOL, inflammation (C-reactive protein and interleukin 6 levels), and erythropoietin (EPO) requirements.


RESULTS
617 of 734 (84%) participants reported urine output at baseline, and 163 of 579 (28%), at year 1. Baseline urine output was not associated with survival. Urine output at year 1, indicating preserved RKF, was independently associated with lower all-cause mortality (HR, 0.70; 95% CI, 0.52-0.93; P = 0.02) and a trend toward lower cardiovascular mortality (HR, 0.69; 95% CI, 0.45-1.05; P = 0.09). Participants with urine output at baseline reported better QOL and had lower C-reactive protein (P = 0.02) and interleukin 6 (P = 0.03) levels. Importantly, EPO dose was 12,000 U/wk lower in those with urine output at year 1 compared with those without (P = 0.001).


CONCLUSIONS
Urine volume was measured in only a subset of patients (42%), but agreed with self-report (P < 0.001).


CONCLUSIONS
RKF in hemodialysis patients is associated with better survival and QOL, lower inflammation, and significantly less EPO use. RKF should be monitored routinely in hemodialysis patients. The development of methods to assess and preserve RKF is important and may improve dialysis care.
Shafi
Tariq
T
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224-2780, USA.
Jaar
Bernard G
BG
Plantinga
Laura C
LC
Fink
Nancy E
NE
Sadler
John H
JH
Parekh
Rulan S
RS
Powe
Neil R
NR
Coresh
Josef
J
D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality; D004921:Erythropoietin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D006435:Renal Dialysis; D014556:Urine
D004921:Erythropoietin