Vitamin D deficiency in dialysis patients: effect of dialysis modality and implications on outcome.
OBJECTIVE
Vitamin D deficiency has been linked to cardiovascular disease and mortality in hemodialysis (HD) patients. The purpose of the present cross-sectional study was to analyze the Vitamin D status of dialysis patients from a single center, study determinants of Vitamin D deficiency, and assess its implications on outcome.


METHODS
A prospective observational study of 115 prevalent dialysis patients was carried out, in which clinical and dialysis-related characteristics including routine biochemistry were studied in relation to levels of 25-hydroxyvitamin-D (25[OH]D, chemiluminescence). Survival was assessed after a median follow-up period of 413 days.


RESULTS
25(OH)D deficiency and insufficiency was present in 51% and 42% of the patients, respectively. Only 7% of the patients showed normal 25(OH)D levels. Peritoneal dialysis patients presented the lowest 25(OH)D levels. Also, a significant difference was found between on-line hemodiafiltration (OL-HDF) and conventional HD (11 [6 to 16] versus 19 [13 to 27] ng/mL; P < 0.001; 25th to 75th percentiles, conventional HD versus OL-HDF respectively). In multinomial logistic regression analysis, patients on conventional HD had 8.35 greater odds (95% CI [2.04 to 34.20]) of 25(OH)D deficiency than OL-HDF even after adjustment for sex, parathyroid hormone, pH, and Charlson comorbidity index. During the follow-up period, 18 patients died. Both crude and adjusted (hazard ratio, 6.96; 95% CI [1.44 to 33.64]) Cox analysis identified 25(OH)D deficiency as a mortality risk factor.


CONCLUSIONS
This observational study underlines the high prevalence of hypovitaminosis D in dialysis patients and its strong implications on outcome. Furthermore, our results suggest that OL-HDF was associated with a better preservation of the vitamin D status as compared with conventional HD.
Gracia-Iguacel
Carolina
C
Division of Renal Medicine, Severo Ochoa University Hospital, Madrid, Spain.
Gallar
Paloma
P
Qureshi
Abdul R
AR
Ortega
Olimpia
O
Mon
Carmen
C
Ortiz
Milagros
M
Villarreal
Isabel
I
Garcia-Lacalle
Concepcion
C
Olieta
Aniana
A
Sánchez
Maria
M
Herrero
Juan C
JC
Vigil
Ana
A
Lindholm
Beng
B
Carrero
Juan J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D013030:Spain / Q000453:epidemiology; D016896:Treatment Outcome; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy*
D014807:Vitamin D