title: Early predictors of hypocalcemia after total thyroidectomy: an analysis of 304 patients using a short-stay monitoring protocol.
abstract: OBJECTIVE
  Postoperative hypocalcemia is common after total thyroidectomy, and perioperative monitoring of serum calcium levels is arguably the primary reason for overnight hospitalization. Confidently predicting which patients will not develop significant hypocalcemia may allow for a safe earlier discharge.
  
  
  OBJECTIVE
  To examine associations of patient characteristics with hypocalcemia, duration of hospitalization, and postoperative intact parathyroid hormone (IPTH) level after total thyroidectomy.
  
  
  METHODS
  Retrospective study of consecutive patients who underwent total thyroidectomy by a single high-volume surgeon between February 1, 2010, and November 30, 2012. Postoperative serum 25-hydroxyvitamin D (vitamin D), calcium, and IPTH levels were tested within 6 to 8 hours after surgery. Mild hypocalcemia was defined as any postoperative serum calcium level of less than 8.4 to 8.0 mg/dL. Significant hypocalcemia was defined as any postoperative serum calcium level of less than 8.0 mg/dL or the development of hypocalcemia-related symptoms.
  
  
  METHODS
  Total thyroidectomy.
  
  
  METHODS
  Associations of patient demographic and clinical characteristics and laboratory values with postoperative mild and significant hypocalcemia were examined using univariate analysis, and independent predictors of hypocalcemia, duration of hospitalization, and IPTH level were determined using multivariate analysis.
  
  
  RESULTS
  Overall, 304 total thyroidectomies were performed. Mild and significant hypocalcemia occurred in 68 (22.4%) and 91 (29.9%) patients, respectively, of which the majority were female (P = .003). The development of significant hypocalcemia was associated with postoperative IPTH level (P < .001). On multivariate analysis, males had a decreased risk of developing mild (odds ratio, 0.37 [95% CI, 0.16-0.85]) and significant (odds ratio, 0.57 [95% CI, 0.09-0.78]) hypocalcemia. Every 10-pg/mL increase in postoperative IPTH level predicted a 43% decreased risk of significant hypocalcemia (P < .001) and an 18% decreased risk of hospitalization beyond 24 hours (P = .03). Presence of malignant neoplasm carried a 27% risk of mild hypocalcemia (P = .02). There was a progressively increasing risk of lower IPTH levels for each parathyroid gland inadvertently resected or autotransplanted. Male sex and African American race were independently predictive of higher IPTH levels.
  
  
  CONCLUSIONS
  Low postoperative IPTH level, female sex, and presence of malignant neoplasm are all significant, independent predictors of hypocalcemia after total thyroidectomy. Clinicians should consider these variables when deciding how to best manage or prevent postoperative hypocalcemia.
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Salem I
authors.initials: SI
authors.lastname: Noureldine
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Dane J
authors.initials: DJ
authors.lastname: Genther
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Michael
authors.initials: M
authors.lastname: Lopez
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Nishant
authors.initials: N
authors.lastname: Agrawal
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Tufano
mesh_terms: D000368:Aged; D000465:Algorithms; D002277:Carcinoma / Q000601:surgery; D002291:Carcinoma, Papillary; D005260:Female; D006042:Goiter / Q000601:surgery*; D006801:Humans; D006996:Hypocalcemia / Q000175:diagnosis / Q000453:epidemiology*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D037981:Neck Dissection; D010281:Parathyroid Hormone / Q000097:blood; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D018570:Risk Assessment; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D010281:Parathyroid Hormone