title: Impact of antiretroviral regimen switches on adherence.
abstract: OBJECTIVE
  An understanding of the situations in which adherence lapses occur is critical to the design of effective interventions to enhance adherence. We investigated whether a switch in antiretroviral medications affected adherence by examining a prospective observational cohort of 128 patients who began a new antiretroviral regimen.
  
  
  METHODS
  Adherence was measured using electronic devices, pill counts, and self-reports, which were combined into a composite adherence measure and expressed as the proportion of prescribed medication taken.
  
  
  RESULTS
  During 1,056 person-months of follow-up, 129 medication regimen changes occurred among 84 patients (66% of participants). Among the 89 analyzable switches (representing 66 patients), the most common reasons for switch included pill to liquid ritonavir (n = 26), gastrointestinal intolerance (n = 11), virologic failure (n = 8), and peripheral neuropathy (n = 7). Overall, mean adherence prior to regimen switch exceeded mean adherence after regimen switch (0.75 vs. 0.70; p =.035). Among subgroups of switches, adherence decreased significantly after switching from pill to liquid ritonavir (0.83 vs. 0.68; p <.001). When this group was excluded, there was no change in adherence after switches (0.72 vs. 0.71; p =.74).
  
  
  CONCLUSIONS
  Antiretroviral regimen changes are not associated with adherence improvement and may be associated with declining adherence when a new regimen is unpalatable. Antiretroviral regimen changes should trigger reassessment of adherence and, when appropriate, adherence intervention.
authors.affiliation: Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, California 90509, USA. lgmiller@ucla.edu
authors.forename: Loren G
authors.initials: LG
authors.lastname: Miller
authors.forename: Carol E
authors.initials: CE
authors.lastname: Golin
authors.forename: Ron D
authors.initials: RD
authors.lastname: Hays
authors.forename: Honghu
authors.initials: H
authors.lastname: Liu
authors.forename: C Keith
authors.initials: CK
authors.lastname: Beck
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Kaplan
authors.forename: Neil S
authors.initials: NS
authors.lastname: Wenger
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D002985:Clinical Protocols; D004304:Dosage Forms; D024882:Drug Resistance, Viral; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000523:psychology*; D006801:Humans; D008297:Male; D010349:Patient Compliance
chemical_list: D019380:Anti-HIV Agents; D004304:Dosage Forms