title: Preoperative vitamin D deficiency predicts postoperative hypocalcemia after total thyroidectomy.
abstract: BACKGROUND
  Transient postthyroidectomy hypocalcemia occurs in up to 30% of patients. We evaluated the effect of vitamin D deficiency on postthyroidectomy hypocalcemia.
  
  
  METHODS
  Data were collected prospectively between January 2006 and March 2009. A total of 166 consecutive total thyroidectomies were analyzed regarding the relation between preoperative vitamin D3 levels and postoperative corrected calcium levels. Patients were divided into three groups dependent upon the preoperative vitamin D3 level: group 1, <25 nmol/l; group 2, 25-50 nmol/l; group 3, >50 nmol/l (conversion factor of 2.5× between nanomoles per liter and nanograms per milliliter). Hypocalcemia was defined as a postoperative calcium level<2.00 mmol/l (8 mg/dl). Hospital length of stay was recorded.
  
  
  RESULTS
  There was a difference in postoperative hypocalcemia between the three vitamin D3 groups (group 1 (32%) vs. group 2 (24%) vs. group 3 (13%). Hypocalcemia in group 1 (vit D<25 nmol/l, <10 ng/ml) was significantly more likely than in group 3 (vit D>50 nmol/l, >20 ng/ml) (P=0.025, χ2 test. Vitamin D3 deficiency was also associated with a longer hospital stay (median stay 2 days vs. 1 day, P<0.001, Wilcoxon rank test).
  
  
  CONCLUSIONS
  There is a significant difference in postoperative hypocalcemia rates between those with vitamin D levels>50 nmol/l (>20 ng/ml) and those with a level of <25 nmol/l (<10 ng/ml). Vitamin D deficiency leads to a delay in discharge owing to a higher likelihood of hypocalcemia.
authors.affiliation: Department of Endocrine Surgery, Hammersmith Hospital, Imperial College NHS Trust, Du Cane Road, London, W12 0HS, UK.
authors.forename: James
authors.initials: J
authors.lastname: Kirkby-Bott
authors.forename: Haridimos
authors.initials: H
authors.lastname: Markogiannakis
authors.forename: Anita
authors.initials: A
authors.lastname: Skandarajah
authors.forename: Matthew
authors.initials: M
authors.lastname: Cowan
authors.forename: Bill
authors.initials: B
authors.lastname: Fleming
authors.forename: Fausto
authors.initials: F
authors.lastname: Palazzo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013965:Thyroidectomy; D014808:Vitamin D Deficiency / Q000150:complications*; D055815:Young Adult