title: Incidence of abacavir hypersensitivity reactions in euroSIDA.
abstract: BACKGROUND
  The aim of the study was to investigate the incidence of abacavir-related hypersensitivity reaction (HSR) and associated deaths in EuroSIDA HIV-1-infected patients.
  
  
  METHODS
  Poisson regression models were developed to compare incidence of abacavir discontinuation according to the line of therapy within which abacavir was received, geographical regions, calendar time and drug formulation (abacavir/lamivudine combination tablet versus abacavir as a single drug or abacavir/zidovudine/lamivudine combination).
  
  
  RESULTS
  Of 3,278 patients that started abacavir, 2,101 (64.1%) discontinued. Of these, 167 (5.1%) discontinued abacavir within 3 months due to HSR with an incidence of 22.1 (95% confidence interval [CI] 18.7-25.4) per 100 person-years of follow-up. After adjustment for gender, prior AIDS, hepatitis C serostatus, baseline CD4+ T-cell count, region and calendar time, HSR incidence was significantly higher in those starting abacavir in a first-line regimen compared with second-line (incidence rate ratio [IRR] 2.04 [95% CI 1.24-3.38]; P=0.005). There was no significant difference between regions. HSR incidence from 2005 onwards was significantly lower compared with 1999-2000 (IRR 0.54 [95% CI 0.32-0.92]; P=0.024). There was a lower observed incidence in patients starting abacavir/lamivudine compared with other formulations (IRR 0.33 [95% CI 0.13-0.88]; P=0.027), however, available data were limited.
  
  
  CONCLUSIONS
  Incidence of abacavir-related HSR is higher in patients starting abacavir in first-line therapy, which could indicate increased over-diagnosis. HSR incidence has decreased in recent years, which might reflect the wider availability of genetic screening and improved awareness of symptoms. There were no reported deaths due to abacavir HSR.
authors.affiliation: Royal Free and University College Medical School, London, UK. w.bannister@pcps.ucl.ac.uk
authors.forename: Wendy P
authors.initials: WP
authors.lastname: Bannister
authors.forename: Nina
authors.initials: N
authors.lastname: Friis-Møller
authors.forename: Amanda
authors.initials: A
authors.lastname: Mocroft
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Viard
authors.forename: Jan
authors.initials: J
authors.lastname: van Lunzen
authors.forename: Ole
authors.initials: O
authors.lastname: Kirk
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Gargalianos
authors.forename: Dénes
authors.initials: D
authors.lastname: Bánhegyi
authors.forename: Antonio
authors.initials: A
authors.lastname: Chiesi
authors.forename: Jens D
authors.initials: JD
authors.lastname: Lundgren
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D015331:Cohort Studies; D015224:Dideoxynucleosides / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D004334:Drug Administration Schedule; D004342:Drug Hypersensitivity / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D004359:Drug Therapy, Combination; D005060:Europe; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000401:mortality / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D015994:Incidence; D019259:Lamivudine / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects*; D016896:Treatment Outcome; D015215:Zidovudine / Q000008:administration & dosage; D000099227:Abacavir
chemical_list: D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D019259:Lamivudine; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D000099227:Abacavir