title: Clinical and demographic predictors for vitamin D deficiency in multiethnic Asian patients with chronic kidney disease.
abstract: BACKGROUND
  Vitamin D deficiency is common in patients with chronic kidney disease (CKD) and can cause skeletal and extraskeletal complications. The purpose of this study is to determine the clinical and demographic risk factors for vitamin D deficiency in multiethnic CKD patients in Singapore, a sun-rich country, so that patients at risk can be identified and treated early.
  
  
  METHODS
  Pre-dialysis CKD patients from the National University Hospital (NUH), Singapore, Outpatient Renal Clinic who had their serum 25-hydroxyvitamin D [25(OH)D] levels measured between January 2008 and October 2010 were included. Their clinical and demographic parameters were collected from hospital databases and medical charts. Logistic regression was used to identify potential predictors for vitamin D deficiency in these patients. Two models, Mt30 and Mt16, were built using threshold serum 25(OH)D levels of ≤30 and <16 ng/mL, respectively.
  
  
  RESULTS
  Of the 219 patients included, 82.7 and 25.6% had serum 25(OH)D levels ≤30 and <16 ng/mL, respectively. Predictors identified for vitamin D deficiency include absence of vitamin D supplementation, type 2 diabetes mellitus (DM), non-cancer diagnosis, younger age, Malay race, treatment with calcitriol and higher serum bicarbonate (CO2) levels. Common predictors for the two models were lack of vitamin D supplementation and DM. The areas under the receiver-operating characteristic (ROC) curve for the validation sets were 0.697 and 0.687 for the Mt30 and Mt16 models, respectively.
  
  
  CONCLUSIONS
  Vitamin D deficiency is common among multiethnic CKD patients in Singapore. Risk factors identified in this study include absence of vitamin D supplementation, DM, non-cancer diagnosis, young age, Malay race, calcitriol treatment and higher serum CO2. The knowledge of these risk factors is useful for predicting vitamin D deficiency in CKD patients in Singapore.
authors: Department of Pharmacy, Faculty of Science , National University of Singapore , Singapore.
authors: Zhong Yi
authors: ZY
authors: Loh
authors: Department of Pharmacy, Faculty of Science , National University of Singapore , Singapore.
authors: Chun Wei
authors: CW
authors: Yap
authors: Department of Medicine, Division of Nephrology , National University Hospital, Singapore , Singapore.
authors: Anantharaman
authors: A
authors: Vathsala
authors: Department of Pharmacy, Faculty of Science , National University of Singapore , Singapore ; Department of Medicine, Division of Nephrology , National University Hospital, Singapore , Singapore.
authors: Priscilla
authors: P
authors: How
keywords: 25-hydroxyvitamin D; chronic kidney disease; mineral and bone disorder; risk factors; vitamin D deficiency