title: Adherence to treatment for recently acquired hepatitis C virus (HCV) infection among injecting drug users.
abstract: OBJECTIVE
  Adherence to HCV therapy impacts sustained virological response (SVR) but there are limited data on adherence, particularly among injecting drug users (IDUs). We assessed 80/80 adherence (≥80% of PEG-IFN doses, ≥80% treatment), on-treatment adherence, and treatment completion in a study of treatment of recent HCV infection (ATAHC).
  
  
  METHODS
  Participants with HCV received pegylated interferon (PEG-IFN) alfa-2a (180μg/week, n=74) and those with HCV/HIV received PEG-IFN alfa-2a with ribavirin (n=35), for a planned 24 weeks. Logistic regression analyses were used to identify predictors of PEG-IFN 80/80 adherence.
  
  
  RESULTS
  A total of 109 out of 163 patients received treatment (HCV, n=74; HCV/HIV, n=35), with 75% ever reporting IDU. The proportion with 80/80 PEG-IFN adherence was 82% (n=89). During treatment, 14% missed ≥1 dose (on-treatment adherence=99%). Completion of 0-4, 5-19, 20-23, and all 24 weeks of PEG-IFN therapy occurred in 10% (n=11), 14% (n=15), 6% (n=7) and 70% (n=76) of cases, respectively. Participants with no tertiary education were less likely to have 80/80 PEG-IFN adherence (AOR 0.29, p=0.045). IDU prior to or during treatment did not impact 80/80 PEG-IFN adherence. SVR was higher among those patients with ≥80/80 PEG-IFN adherence (67% vs. 35%, p=0.007), but similar among those with and without missed doses during therapy (73% vs. 60%, p=0.309). SVR in those patients discontinuing therapy between 0-4, 5-19, 20-23, and 24 weeks was 9%, 33%, 43%, and 76%, respectively (p<0.001).
  
  
  CONCLUSIONS
  High adherence to treatment for recent HCV was observed, irrespective of IDU prior to, or during, therapy. Sub-optimal PEG-IFN exposure was mainly driven by early treatment discontinuation rather than missed doses during therapy.
authors.affiliation: National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia. jgrebely@nchecr.unsw.edu.au
authors.forename: Jason
authors.initials: J
authors.lastname: Grebely
authors.forename: Gail V
authors.initials: GV
authors.lastname: Matthews
authors.forename: Margaret
authors.initials: M
authors.lastname: Hellard
authors.forename: David
authors.initials: D
authors.lastname: Shaw
authors.forename: Ingrid
authors.initials: I
authors.lastname: van Beek
authors.forename: Kathy
authors.initials: K
authors.lastname: Petoumenos
authors.forename: Maryam
authors.initials: M
authors.lastname: Alavi
authors.forename: Barbara
authors.initials: B
authors.lastname: Yeung
authors.forename: Paul S
authors.initials: PS
authors.lastname: Haber
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lloyd
authors.forename: John M
authors.initials: JM
authors.lastname: Kaldor
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Dore
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006526:Hepatitis C / Q000188:drug therapy* / Q000635:transmission* / Q000821:virology; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000008:administration & dosage / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000627:therapeutic use; D011446:Prospective Studies; D011994:Recombinant Proteins; D012254:Ribavirin / Q000008:administration & dosage / Q000627:therapeutic use; D015819:Substance Abuse, Intravenous / Q000150:complications*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins; D011092:Polyethylene Glycols; D012254:Ribavirin; C100416:peginterferon alfa-2a