title: Incidence of abnormal liver biochemical tests in hyperthyroidism.
abstract: OBJECTIVE
  Abnormal serum liver function tests are common in patients with untreated thyrotoxicosis, even prior to the initiation of antithyroidal medications that may worsen the severity of the abnormal serum liver biochemistries. There is a wide range of the incidence of these abnormalities in the published literature. The aim of this study was to assess the risks factors and threshold of thyrotoxicosis severity for developing an abnormal liver biochemical test upon the diagnosis of new thyrotoxicosis.
  
  
  METHODS
  Single-institution retrospective cohort study.
  
  
  METHODS
  Patients of ≥18 years old receiving medical care at a large, academic, urban US medical centre between 2002-2016.
  
  
  METHODS
  Inclusion criteria were a serum thyroid stimulating hormone (TSH) concentration of <0·3 mIU/l or ICD-9 code for thyrotoxicosis, with thyrotoxicosis confirmed by either a concurrent elevated serum triiodothyronine (T3) or thyroxine (T4) concentration ([total or free] within 3 months), and an available liver biochemical test(s) within 6 months of thyrotoxicosis. The biochemical liver tests assessed were serum aspartate transaminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), gamma-glutamyltransferase (GGT), total bilirubin, and conjugated bilirubin concentrations.
  
  
  RESULTS
  In this cohort of 1514 subjects, the overall incidence of any biochemical liver test abnormality within 6 months of thyrotoxicosis was 39%. An initial serum TSH concentration <0·02 mIU/l, male gender, and African-American race were significant predictors of an abnormal serum liver biochemical test within 6 months of the diagnosis of new-onset untreated thyrotoxicosis.
  
  
  CONCLUSIONS
  This study identifies risk factors for patients who develop an abnormal serum liver biochemical test result within 6 months of a diagnosis of untreated thyrotoxicosis.
authors.affiliation: UCLA David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Tiffany Y
authors.identifier: http://orcid.org/0000-0003-4943-0004
authors.initials: TY
authors.lastname: Lin
authors.affiliation: Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Anshula O
authors.initials: AO
authors.lastname: Shekar
authors.affiliation: Department of Biomathematics, UCLA David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, UCLA David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Yeh
authors.affiliation: Division of Gastroenterology, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, USA.
authors.forename: Sammy
authors.initials: S
authors.lastname: Saab
authors.affiliation: Sansum Clinic, Santa Barbara, CA, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Wilson
authors.affiliation: Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, USA.|Division of Endocrinology, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Leung
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D015994:Incidence; D008107:Liver Diseases / Q000097:blood*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013971:Thyrotoxicosis / Q000097:blood*