title: Is 1 alanine transaminase >200 IU enough to define an alanine transaminase flare in HIV-infected populations? A new definition derived from a large cohort study.
abstract: OBJECTIVE
  Recent studies have suggested that highly active antiretroviral therapy may lead to rises in alanine transaminase (ALT) among HIV-infected patients. However, the definition of an ALT flare is arbitrary and the extent to which such increases represent normal fluctuations has not been explored.
  
  
  METHODS
  Using data from untreated, hepatitis B virus/hepatitis C virus-negative, HIV-infected patients, we derived a definition for an ALT flare by exploring a series of ALT thresholds (from 100 to 200 IU/L). The resulting definition (2 consecutive ALTs > 200 measured >2 weeks apart) was applied to all patients in the UK Collaborative HIV Cohort (CHIC) Study, and Poisson regression was used to identify factors associated with ALT flares.
  
  
  RESULTS
  Five hundred and twenty six of 12,206 eligible patients (4.3%) had > or =1 ALT flare, resulting in a total of 615 episodes of ALT flares. The overall rate of an ALT flare was 1.19 (95% confidence interval: 1.10 to 1.28) per 100 person-years. Higher risk of ALT flare was associated with lower CD4 counts, detectable viral loads, being under follow-up in earlier calendar years, prior clinical AIDS, receipt of nevirapine either with didanosine/stavudine or without didanosine/stavudine, receipt of ritonavir, detectable anti-hepatitis C virus, and detectable hepatitis B surface antigen.
  
  
  CONCLUSIONS
  Associations between known risk factors may be under/over estimated if using single values, that is, 1 ALT > 200, to define ALT flares. We recommend studies to use a more stringent measure and suggest our derived definition of an ALT flare.
authors: Research Department of Infection and Population Health, University College London Medical School, London, UK. l.bansi@pcps.ucl.ac.uk
authors: Loveleen
authors: L
authors: Bansi
authors: Jo
authors: J
authors: Turner
authors: Richard
authors: R
authors: Gilson
authors: Frank
authors: F
authors: Post
authors: Brian
authors: B
authors: Gazzard
authors: Clifford
authors: C
authors: Leen
authors: Jane
authors: J
authors: Anderson
authors: Kholoud
authors: K
authors: Porter
authors: Teresa
authors: T
authors: Hill
authors: Martin
authors: M
authors: Fisher
authors: Jonathan
authors: J
authors: Ainsworth
authors: Deenan
authors: D
authors: Pillay
authors: Margaret
authors: M
authors: Johnson
authors: Alan
authors: A
authors: Winston
authors: Chloe
authors: C
authors: Orkin
authors: Philippa
authors: P
authors: Easterbrook
authors: Andrew
authors: A
authors: Phillips
authors: Caroline
authors: C
authors: Sabin
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D019380:Anti-HIV Agents / Q000627:therapeutic use; D023241:Antiretroviral Therapy, Highly Active; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D006509:Hepatitis B / Q000150:complications; D006526:Hepatitis C / Q000150:complications; D006801:Humans; D008297:Male
chemical_list: D019380:Anti-HIV Agents; D000410:Alanine Transaminase