title: A prospective study on the causes of notably raised alanine aminotransferase (ALT).
abstract: OBJECTIVE
  High levels of alanine aminotransferase (ALT) can be a marker of severe liver disease with variable aetiologies and prognosis. Very few prospective studies have been undertaken on the aetiology and prognosis of patients with high ALT levels. No population-based prospective study has systematically evaluated drug-induced liver injury (DILI) among these patients. The objective was to determine the aetiology and prognosis of patients with high ALT.
  
  
  METHODS
  In a catchment area of 160,000 inhabitants, a population-based prospective study identified all adult patients with serum level of ALT >500 U/L during a 12-month period. All underwent thorough diagnostic work-up and follow-up. In suspected DILI, causality was assessed with Roussel Uclaf Causality Assessment Method.
  
  
  RESULTS
  A total of 155 patients were identified with ALT >500 U/L, 12 children and one with ALT of non-liver-related origin, leaving 142 patients for the analysis: 73 (51%) males, median age 52 (IQR 36-68, range 19-89 years). The most common causes were choledocholithiasis 48/142 (34%), ischaemic hepatitis 26 (18%), viral hepatitis 16 (11%) and DILI 15 (11%), hepatobiliary malignancy (n = 6), surgery/interventions (n = 8) and other aetiologies (n = 23). No specific aetiology was found in 6% of cases. In the total study cohort 99 (70%) required hospitalisation, 78 (55%) had jaundice and 22 (16%) died, liver-related death in 10%, 35% in IH and 7% in DILI.
  
  
  CONCLUSIONS
  The most common cause of notably high ALT was choledocholithiasis. Ischaemic hepatitis was a common aetiology with approximately 35% liver-related mortality. Viral hepatitis and DILI were important aetiologies among these patients.
authors.affiliation: a Faculty of Medicine , University of Iceland , Reykjavík , Iceland ;
authors.forename: Helgi Kristinn
authors.initials: HK
authors.lastname: Björnsson
authors.affiliation: b Medical Faculty, Division of Gastroenterology and Hepatology, Department of the Internal Medicine , The National University Hospital of Iceland , Reykjavík , Iceland.
authors.forename: Sigurdur
authors.initials: S
authors.lastname: Olafsson
authors.affiliation: b Medical Faculty, Division of Gastroenterology and Hepatology, Department of the Internal Medicine , The National University Hospital of Iceland , Reykjavík , Iceland.
authors.forename: Ottar M
authors.initials: OM
authors.lastname: Bergmann
authors.affiliation: a Faculty of Medicine , University of Iceland , Reykjavík , Iceland ;|b Medical Faculty, Division of Gastroenterology and Hepatology, Department of the Internal Medicine , The National University Hospital of Iceland , Reykjavík , Iceland.
authors.forename: Einar S
authors.initials: ES
authors.lastname: Björnsson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000473:pathology*; D008107:Liver Diseases / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; D000410:Alanine Transaminase
keywords: Aetiology; alanine aminotransferase; liver disease; outcome