Ethnic differences in 25-hydroxyvitamin D levels and response to treatment in CKD.
OBJECTIVE
Nutritional vitamin D [25(OH)D] deficiency is common in patients with chronic kidney disease (CKD). No studies have specifically examined the differences between ethnic groups in response to ergocalciferol ("D2") therapy.


METHODS
A retrospective analysis was performed to evaluate the effectiveness of D2 therapy as recommended by the KDOQI guidelines in 184 Hispanic and Caucasian nondialysis CKD patients.


RESULTS
Low 25(OH)D levels (<75 nmol/L) were found in 89.4 % of Hispanics versus 61.4 % of Caucasians, despite similar degrees of CKD. Treatment per KDOQI guidelines resulted in 85.5 % of treated Hispanics and 66.7 % of treated Caucasians remaining vitamin D-deficient. Although both Hispanics and Caucasians had significant (P < 0.0001) changes in 25(OH)D levels, absolute changes were modest (12.5 ± 2.0 nmol/mL in Hispanics, 20.0 ± 3.5 nmol/L in Caucasians). The increase seen in Caucasians was significantly greater than in Hispanics (P < 0.0001). In multiple logistic regression modeling, Hispanic ethnicity remained independently associated with poorer response to therapy (P = 0.0055), even after adjustment for other factors.


CONCLUSIONS
While both Hispanics and Caucasians demonstrated suboptimal response to the KDOQI-guided vitamin D repletion strategy, Hispanic ethnicity was significantly associated with poorer response. Our findings may have implications for other darker-skinned populations, even in solar-rich environments.
South Texas Kidney Specialists, PA, McAllen, TX, USA.
Iris
I
Sanchez
Roberto
R
Mangoo-Karim
Jason R
JR
Stubbs
George P
GP
Yanev
James B
JB
Wetmore
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood; D003404:Creatinine / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood; D019587:Dietary Supplements; D004872:Ergocalciferols / Q000627:therapeutic use*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D011507:Proteinuria / Q000097:blood / Q000150:complications; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000208:ethnology*; D012189:Retrospective Studies; D013781:Texas; D016896:Treatment Outcome; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000150:complications / Q000188:drug therapy* / Q000208:ethnology*; D014815:Vitamins / Q000627:therapeutic use*; D044465:White People; D055815:Young Adult
D004872:Ergocalciferols; D010281:Parathyroid Hormone; D010710:Phosphates; D014815:Vitamins; D014807:Vitamin D; D003404:Creatinine; D002118:Calcium