title: The significance of elevated levels of parathyroid hormone in patients with morbid obesity before and after bariatric surgery.
abstract: OBJECTIVE
  The risk of hyperparathyroidism after the duodenal switch operation is related to the length of the common channel.
  
  
  METHODS
  A retrospective analysis of patients following the duodenal switch operation from October 2, 2000, through February 1, 2002.
  
  
  METHODS
  Academic tertiary referral hospital.
  
  
  METHODS
  One hundred sixty-five consecutive patients underwent the duodenal switch operation, performed for morbid obesity, with common channel lengths of 75 cm (n = 103 [group A]) and 100 cm (n = 62 [group B]).
  
  
  METHODS
  Weight loss and parathyroid hormone, corrected calcium, and 25-hydroxyvitamin D (25-OH D) levels were compared between groups A and B. Values were determined preoperatively, early postoperatively (3-6 months), and late postoperatively (9-18 months).
  
  
  RESULTS
  Both groups exhibited a slight reduction in serum calcium concentration, with one quarter decreasing below the normal range. Hyperparathyroidism was more common in group A than group B preoperatively (38.9% vs 14.9%), reflecting the higher body mass index of patients in group A. Hyperparathyroidism was also more frequent in the early (54.9% vs 30.9%) and late (49.4% vs 20.5%) postoperative periods in group A vs group B. New-onset hyperparathyroidism was also more common in group A than group B (42.0% vs 13.3%). After 1 year, subnormal 25-OH D levels were found in 17.0% of the patients in group A and in 10.0% of the patients in group B. Median 25-OH D levels increased in both groups, but tended to be higher in group B.
  
  
  CONCLUSIONS
  Patients with shorter common channels had a higher risk of developing hyperparathyroidism. This may be related to limited 25-OH D absorption.
authors.affiliation: Department of Surgery, University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Nahid
authors.initials: N
authors.lastname: Hamoui
authors.forename: Kiwan
authors.initials: K
authors.lastname: Kim
authors.forename: Gary
authors.initials: G
authors.lastname: Anthone
authors.forename: Peter F
authors.initials: PF
authors.lastname: Crookes
mesh_terms: D000328:Adult; D002118:Calcium / Q000097:blood; D016022:Case-Control Studies; D004386:Duodenum / Q000601:surgery*; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood*; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D015431:Weight Loss
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium