Vitamin D deficiency in a Spanish cohort of patients with chronic kidney disease

Background and objective: Vitamin D (25-OH-D-3) deficiency is an emerging global health problem. Chronic kidney disease (CKD) patients have a higher risk of this deficiency. We aimed to determine the prevalence of 25-OH-D-3 deficiency in a cohort of CKD patients in an urban area of Spain and its relationship with cardiovascular disease (CVD). Patients and methods: We evaluated the prevalence of 25-OH-D-3 deficiency in 751 incident patients referred to our outpatient clinic (male gender 59.3%, mean age 67.2 [+/- 15] years, mean GFR (MDRD-4) 47.9 +/- 25.5 ml/min/1.73 m(2)) with different stages of CKD. We excluded end stage renal disease patients and with kidney transplant. Clinical data and biochemical parameters related to bone and mineral metabolism were recorded. Levels of 25-OH-D-3 < 15 ng/ml were considered to be deficient. Results: The mean 25-OH-D-3 levels were 17.06 [+/- 12.93] ng/ml. Only 10% of our patients had adequate 25-OH-D-3 levels (>30 ng/ml) and 51% showed deficient levels. 25-OH-D-3 deficiency worsened with the progression of CKD (P < .05). Elderly people (P = .001), female gender (P = .02), and diabetes (P = .03) were closely associated with 25-OH-D-3 deficiency. 25-OH-D-3 deficiency was inversely associated with serum PTH (P = .02), and directly associated with serum calcium (P < .004). Patients with a history of CVD had lower 25-OH-D-3 levels (P = .038). Conclusions: 25-OH-D-3 deficiency has a high prevalence in CKD patients, and the severity increases with the progression of kidney disease. Elderly, women and diabetic patients have a higher risk of 25-OH-D-3 deficiency. 25-OH-D-3 deficiency was related to higher levels of PTH and lower serum calcium. (C) 2012 Elsevier Espana, S.L. All rights reserved.