title: Parathyroid hormone response to two levels of vitamin D deficiency is associated with high risk of medical problems during hospitalization in patients with hip fracture.
abstract: BACKGROUND
  Vitamin D and the parathyroid hormone (PTH) response play an important role in hip fracture patients. This study was carried out to determine the factors associated with the PTH response to different levels of vitamin D deficiency during hospitalization.
  
  
  METHODS
  This was a cross-sectional study of patients over 64 years of age admitted with an acute fragility hip fracture between March 1st 2009 and November 30th 2012. Demographic, clinical, functional, and cognitive function were evaluated at admission and during hospitalization. Levels of 25-hydroxyvitamin D (25-OHD) and PTH were analyzed. Two 25-OHD cut-off points were considered, <12 ng/ml and 12-20 ng/ml. Multivariate logistic regression analysis was used.
  
  
  RESULTS
  Mean age of the 607 patients included was 84.7 years (SD 7.10), and 81.9 % were women. The mean 25-OHD level in the total sample was 13.2 (SD 11.1) ng/ml. Levels of 25-OHD <12 ng/ml were present in 347 patients (57.2 %), of whom 158 (45.5 %) had secondary hyperparathyroidism (SHPT) (PTH >65 pg/ml). 25-OHD levels of 12-20 ng/ml were present in 168 (27.7 %) patients, of whom 47 (28 %) had SHPT. Following logistic regression, SHPT was associated in both groups (25-OHD <12 and 12-20 ng/ml) with a greater number of medical problems during hospitalization. In the 25-OHD group <12 ng/ml, SHPT was also associated with poorer glomerular filtration rates.
  
  
  CONCLUSIONS
  The PTH response to vitamin D deficiency in hip fracture patients may be a marker for patients with higher risk of developing multiple medical problems, both when considering severe (<12 ng/ml) and moderate (12-20 ng/ml) vitamin D deficiency.
authors.affiliation: Servicio de Geriatría, Hospital Universitario La Paz, IdiPaz, Paseo Castellana 261, 28046, Madrid, Spain. mteresa.alarcon@salud.madrid.org.
authors.forename: T
authors.initials: T
authors.lastname: Alarcón
authors.affiliation: Servicio de Geriatría, Hospital Universitario La Paz, IdiPaz, Paseo Castellana 261, 28046, Madrid, Spain.
authors.forename: J I
authors.initials: JI
authors.lastname: González-Montalvo
authors.affiliation: Servicio de Geriatría, Hospital Universitario La Paz, IdiPaz, Paseo Castellana 261, 28046, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Hoyos
authors.affiliation: Servicio de Bioestadística, Hospital Universitario La Paz, IdiPaz, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Diez-Sebastián
authors.affiliation: Departamento de Medicina Preventiva y Salud Pública, Universidad Autónoma de Madrid. IdiPaz, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Otero
authors.affiliation: Servicio de Traumatología, Hospital Universitario La Paz, IdiPaz, Madrid, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Mauleon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006620:Hip Fractures / Q000097:blood* / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Elderly; Hip fracture; Outcomes; Secondary hyperparathyroidism; Vitamin D