title: Incidence of permanent hypocalcaemia after total thyroidectomy with or without central neck dissection for thyroid carcinoma: a nationwide claim study.
abstract: Permanent hypocalcaemia is the most common and serious complication after total thyroidectomy (TT). This study examined the impact of central neck dissection (CND) and institutional volume on rates of permanent hypocalcaemia by analysing data held in the nationwide claim database of South Korea.
  
  
  
  Data from patients who underwent TT due to thyroid carcinoma from 2007-2013 were obtained from the Health Insurance Review and Assessment Service database. Of these, patients prescribed more than 1000 mg of elemental calcium for more than 288 days during the first 360 days postsurgery were defined as having permanent hypocalcaemia.
  
  
  
  In total, 192 333 patients (32 988 male and 159 345 female) were eligible for analysis. Of these, 52 707 (27·4%) underwent TT alone and 139 626 (72·6%) underwent TT plus CND. The incidence of permanent hypocalcaemia was greater in the TT plus CND group than in the TT alone group (5·4% vs 4·6%, P < 0·001). The age- and sex-adjusted risk for permanent hypocalcaemia in the TT plus CND group was 1·20 (P < 0·001). CND did not raise the rates of permanent hypocalcaemia in institutes with a low volume of annual cases (<200), whereas permanent hypocalcaemia was more common in the TT plus CND group than in the TT alone group (3·5% vs 2·9%, P = 0·002) in institutes with a large volume of annual cases (≥800).
  
  
  
  TT plus CND was associated with a greater risk of permanent hypocalcaemia than TT alone. Surgeons should consider the risk of permanent hypocalcaemia when deciding whether to perform CND.
authors.affiliation: Health Insurance Review and Assessment Service, Seoul, Korea.
authors.forename: Gi Hyeon
authors.initials: GH
authors.lastname: Seo
authors.affiliation: Department of Surgery, Seoul National University Boramae Medical Center, Dongjak-gu, Seoul, Korea.|Cancer Research Institute, Seoul National University College of Medicine, Jongno-gu, Seoul, Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Chai
authors.affiliation: Department of Anatomy, Seoul National University College of Medicine, Jongno-gu, Seoul, Korea.
authors.forename: Hyung Jin
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Jongno-gu, Seoul, Korea.|Department of Surgery, Seoul National University Hospital and College of Medicine, Jongno-gu, Seoul, Korea.
authors.forename: Kyu Eun
authors.initials: KE
authors.lastname: Lee
mesh_terms: D000328:Adult; D016208:Databases, Factual; D003657:Decision Making; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000209:etiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection / Q000009:adverse effects*; D011183:Postoperative Complications; D056910:Republic of Korea; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000150:complications / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects*; D016896:Treatment Outcome