title: The effect of vitamin D levels on postoperative calcium requirements, symptomatic hypocalcemia, and parathormone levels following parathyroidectomy for primary hyperparathyroidism.
abstract: BACKGROUND
  Low vitamin D-25 is common in primary hyperparathyroidism but the effect of this deficiency on postparathyroidectomy calcium requirements is unclear.
  
  
  METHODS
  A prospective study was conducted on 4 groups based on preoperative vitamin D-25 levels: very low (<20 ng/mL, n = 500); low (21 to 30 ng/mL, n = 500); normal (>30 ng/mL, n = 500); and supplemented (<25 ng/mL supplemented to >40 ng/mL, n = 285). Patients were placed on identical postoperative oral calcium regimens, and hypocalcemia symptoms were recorded. Total calcium requirements for 2 weeks postoperation were calculated and parathormone (PTH) levels were measured for 2-6 months.
  
  
  RESULTS
  Mean vitamin D levels (ng/mL) for each group were: very low (14.2); low (24.4); normal (38.3); and supplemented (16.5 supplemented to 54.3). Postoperative oral calcium requirements (in grams) were identical for all groups (18.7, 18.2, and 18.6, and 19.0, respectively, all P = NS); the incidence and timing of hypocalcemia symptoms were nearly identical for all groups: 8.1%, 7.9%, and 7.8% (P = .8). Elevated postsurgical PTH was identical (below 8%) and was not influenced by vitamin D levels.
  
  
  CONCLUSIONS
  The incidence of hypocalcemic symptoms and the postoperative calcium requirements are identical for patients with very low, low, normal, or supplemented (high) vitamin D. The incidence of persistently elevated PTH postoperatively is also unrelated to preoperative vitamin D levels. Vitamin D supplementation from very low to high levels has no clinical benefit.
authors.affiliation: Norman Parathyroid Center, Tampa, FL, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Press
authors.forename: Douglas
authors.initials: D
authors.lastname: Politz
authors.forename: Jose
authors.initials: J
authors.lastname: Lopez
authors.forename: James
authors.initials: J
authors.lastname: Norman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000150:complications / Q000601:surgery*; D006996:Hypocalcemia / Q000097:blood* / Q000188:drug therapy / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy; D011183:Postoperative Complications / Q000097:blood* / Q000188:drug therapy; D011446:Prospective Studies; D014807:Vitamin D / Q000097:blood* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000150:complications / Q000188:drug therapy; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D002118:Calcium