title: Prevalence of abnormal serum vitamin D, PTH, calcium, and phosphorus in patients with chronic kidney disease: results of the study to evaluate early kidney disease.
abstract: Abnormalities of mineral metabolism occur early in chronic kidney disease. Quantification of the prevalence of these abnormalities has not been described using current assays nor in large unselected populations. This outpatient cohort cross-sectional study was conducted in 153 centers, (71% primary care practices). Blood for parathyroid hormone (PTH), vitamin D metabolites, creatinine, calcium (Ca), and phosphorus (P) were drawn between June and October 2004. Low 1,25-dihydroxyvitamin D (1,25 OH2 D3) was defined as <22 pg/ml. The 1814 patients had a mean age of 71.1 years old; 48% had diabetes mellitus (DM). Low 1,25 OH2 D3 was evident at all estimated glomerular filtration rate (eGFR) levels: 13% in those with eGFR >80 ml/min, >60% in those with eGFR <30 ml/min. High PTH (>65pm/dl) occurred in 12% with eGFR >80 ml/min. Serum Ca and P were normal until eGFR was <40 ml/min. Significant differences in the mean and median values of 1,25 OH2 D3, PTH, but not 25(OH)D3 levels, were seen across deciles of eGFR (P<0.001). Multivariate analysis revealed that DM, increased urinary albumin/creatinine ratio and lower eGFR predicted lower values of 1,25 OH2 D3. A high prevalence of mineral metabolite abnormalities occurs in a large unreferred US cohort. Low 1,25 OH2 D3 and elevated PTH are common at higher eGFR than previously described. As bone, cardiovascular disease, and mineral metabolite are correlated; further studies are necessary to determine the importance of these findings relative to outcomes.
authors.affiliation: Department of Nephrology, University of British Columbia, Vancouver, BC, Canada. alevin@providencehealth.bc.ca
authors.forename: A
authors.initials: A
authors.lastname: Levin
authors.forename: G L
authors.initials: GL
authors.lastname: Bakris
authors.forename: M
authors.initials: M
authors.lastname: Molitch
authors.forename: M
authors.initials: M
authors.lastname: Smulders
authors.forename: J
authors.initials: J
authors.lastname: Tian
authors.forename: L A
authors.initials: LA
authors.lastname: Williams
authors.forename: D L
authors.initials: DL
authors.lastname: Andress
mesh_terms: D000368:Aged; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010758:Phosphorus / Q000097:blood*; D014807:Vitamin D / Q000097:blood*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium