title: Patterns of antiretroviral use in the United States of America: analysis of three observational databases.
abstract: OBJECTIVE
  To characterize patterns of antiretroviral use in HIV-infected patients and explore variation by patient characteristics and disease stage.
  
  
  METHODS
  Three large patient databases recording information derived from routine clinical attendance were analyzed: HIV Insight (n = 10 873), Target Management Services (n = 2226) and Clinical Partners (n = 1505). Each database records the dates of starting and stopping individual antiretroviral agents over time, measurements of CD4 T-cell counts and HIV-RNA levels at approximately 6-monthly intervals, and the demographic characteristics of patients. The number, frequency and duration of different antiretroviral combinations over time and their relationship to stage of HIV-disease and demographic characteristics were explored.
  
  
  RESULTS
  Over 2000 different combinations of antiretroviral agents are recorded. From 1987 onwards, the use of zidovudine increased, with 23% of patients receiving monotherapy by 1990. The majority of treated patients remained on monotherapy until the introduction of highly active antiretroviral therapy (HAART) in 1996. By 1999, the standard of care was HAART, with 84% of patients beginning antiretroviral therapy with HAART. Those of African American race (odds ratio 0.59) and funded by Medicaid (odds ratio 0.72) were significantly less likely to begin antiretroviral therapy on HAART. Until 1995, there was a significant decrease in CD4 T-cell count when starting antiretroviral therapy. No significant trend was observed in either CD4 T-cell count or viral load after this time. Those starting on HAART therapies were significantly less likely to stop or switch regimens than those on nucleoside reverse transcriptase inhibitor (NRTI)-only therapies (P < 0.001).
  
  
  CONCLUSIONS
  Complex patterns of antiretroviral treatment are observed in this large population. Changes over time mirror the introduction of the new antiretroviral agents.
authors.affiliation: Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, London, UK. a.ghani@ic.ac.uk
authors.forename: A C
authors.initials: AC
authors.lastname: Ghani
authors.forename: C A
authors.initials: CA
authors.lastname: Donnelly
authors.forename: R M
authors.initials: RM
authors.lastname: Anderson
mesh_terms: D000328:Adult; D001741:Black or African American; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active / Q000706:statistics & numerical data*; D018791:CD4 Lymphocyte Count; D019992:Databases as Topic; D004359:Drug Therapy, Combination; D005260:Female; D006678:HIV / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy* / Q000208:ethnology / Q000276:immunology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data* / Q000639:trends; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage*; D014481:United States; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors