title: Calcium and phosphorus homeostasis in dogs with spontaneous chronic kidney disease at different stages of severity.
abstract: BACKGROUND
  Studies in dogs with experimental chronic kidney disease (CKD) have demonstrated that abnormalities of calcium-phosphorus (Ca-P) homeostasis occur frequently and have a negative effect on kidney function and survival. However, the prevalence of these alterations in dogs with naturally occurring CKD at different stages of severity has not yet been investigated.
  
  
  OBJECTIVE
  Abnormalities of Ca-P metabolism occur early in the course of CKD with an increased prevalence in more severe stages.
  
  
  METHODS
  Fifty-four dogs with CKD and 22 healthy dogs.
  
  
  METHODS
  Blood and urine samples were obtained for a CBC, biochemistry, determination of parathyroid hormone (PTH), calcitriol, and ionized calcium concentrations and urinalysis. Based on urine protein/creatinine ratio and serum creatinine concentration, dogs were grouped according to the IRIS classification for CKD.
  
  
  RESULTS
  Hyperparathyroidism (HPTH) (PTH > or = 48 pg/mL) was diagnosed in 41 (75.9%) dogs with CKD. Its prevalence increased from 36.4% (stage 1) to 100% (stage 4). Hyperphosphatemia (P > 5.5 mg/dL) was present in 37 (68.5%) dogs; increasing in prevalence from 18% (stage 1) to 100% (stage 4). Receiver-operating characteristic curve analysis showed that serum phosphorus concentration in the 4.5-5.5 mg/dL range correctly identified the presence of HPTH in most dogs. Calcitriol concentration progressively decreased in dogs with CKD and differences became statistically significant by stage 3.
  
  
  CONCLUSIONS
  HPTH and hyperphosphatemia occur frequently in dogs with naturally occurring CKD, even at early stages of CKD in some dogs. These findings highlight the importance of monitoring these parameters early in the course of CKD.
authors.affiliation: Clínica Veterinaria Germanías, Av. República Argentina 44, 46701 Gandía-Valencia, Spain. germanias@vetgermanias.com
authors.forename: O
authors.initials: O
authors.lastname: Cortadellas
authors.forename: M J
authors.initials: MJ
authors.lastname: Fernández del Palacio
authors.forename: J
authors.initials: J
authors.lastname: Talavera
authors.forename: A
authors.initials: A
authors.lastname: Bayón
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D005260:Female; D006706:Homeostasis; D006961:Hyperparathyroidism / Q000175:diagnosis / Q000662:veterinary; D007676:Kidney Failure, Chronic / Q000145:classification / Q000378:metabolism / Q000662:veterinary*; D008297:Male; D010758:Phosphorus / Q000378:metabolism*
chemical_list: D010758:Phosphorus; D002118:Calcium