Lower retinol levels as an independent predictor of mortality in long-term hemodialysis patients: a prospective observational cohort study.
BACKGROUND
Malnutrition, inflammation, and oxidative stress are inter-related mechanisms linked to the progression of cardiovascular disease and prognosis of long-term hemodialysis (HD) patients. In this study, we focus on antioxidant vitamins and trace elements and the relationship of their serum levels to the prognosis of long-term HD patients.


METHODS
Prospective observational cohort study.


METHODS
261 long-term HD patients prospectively followed up for 5 years (2003-2008). The control group consisted of 66 healthy participants.


METHODS
Retinol, alpha-tocopherol, retinol-binding protein 4 (RBP-4), and the trace elements zinc and selenium.


RESULTS
Mortality and cardiovascular mortality. During follow-up, 146 patients (56%) died, and for 71 of these, death was due to cardiovascular causes.


METHODS
Retinol, alpha-tocopherol, RBP-4, zinc, selenium, and basic nutritional and inflammatory parameters measured at the beginning of the study.


RESULTS
Retinol and RBP-4 levels were significantly increased, whereas retinol:RBP-4 ratio and alpha-tocopherol, selenium, and zinc levels were decreased in HD patients compared with controls (retinol, 168.1 +/ 64.4 microg/dL in HD patients vs 99.1 +/-23.3 [corrected] microg/dL in controls; P<0.001). Lower retinol level was found to be a significant independent predictor of overall and cardiovascular mortality in multivariate Cox analysis (HR, 0.733 [95% CI, 0.599-0.896], P=0.002, and 0.694 [95% CI, 0.511-0.942], P=0.02, per 1 SD, respectively). The worst prognoses for patients with lower retinol levels were observed when these were combined with low albumin levels.


CONCLUSIONS
Sample size, investigation of prevalent, not incident, dialysis patients.


CONCLUSIONS
This is the first study showing a lower retinol level as an independent predictor of overall and cardiovascular mortality in HD patients. It has to be elucidated whether the beneficial effects of higher serum retinol levels should be attributed to only better nutritional support or also to retinol's role in immune response and differentiation.
Kalousová
Marta
M
Institute of Clinical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University in Prague, General University Hospital in Prague, Czech Republic. marta.kalousova@seznam.cz
Kubena
Ales A
AA
Kostírová
Milada
M
Vinglerová
Marie
M
Ing
Oto Mestek
OM
Dusilová-Sulková
Sylvie
S
Tesar
Vladimír
V
Zima
Tomás
T
D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D006435:Renal Dialysis / Q000401:mortality*; D016019:Survival Analysis; D013997:Time Factors; D014801:Vitamin A / Q000097:blood*
D014801:Vitamin A