title: Treatment interruption in a primary care antiretroviral therapy program in South Africa: cohort analysis of trends and risk factors.
abstract: OBJECTIVE
  To investigate antiretroviral treatment (ART) interruption in a long-term treatment cohort in South Africa.
  
  
  METHODS
  All adults accessing ART between 2004 and 2009 were included in this analysis. Defaulting was defined as having stopped all ART drugs for more than 30 days. Treatment interrupters were patients who defaulted and returned to care during the study, whereas loss to follow-up was defined as defaulting and not returning to care. Kaplan-Meier estimates and Poisson regression models were used to analyze rates and determinants of defaulting therapy and of treatment resumption.
  
  
  RESULTS
  Overall rate of defaulting treatment was 12.8 per 100 person-years (95% confidence interval: 11.4 to 14.4). Risk factors for defaulting were male gender, high baseline CD4 count, recency of ART initiation, and time on ART. The probability of resuming therapy within 3 years of defaulting therapy was 42% (event rate = 21.4 per 100 person-years). Factors associated with restarting treatment were female gender, older age, and time since defaulting.
  
  
  CONCLUSIONS
  Defaulting treatment need not be an irreversible event. Interventions to increase retention in care should target men, less immunocompromised patients, and patients during the first 6 months of treatment. Resumption of treatment is most likely within the first year of interrupting therapy.
authors.affiliation: The Desmond TUTU HIV Centre, Institute for Infectious Disease and Molecular Medicine, Faculty of Health Science, University of Cape Town, South Africa. katharina.kranzer@lshtm.ac.uk
authors.forename: Katharina
authors.initials: K
authors.lastname: Kranzer
authors.forename: James J
authors.initials: JJ
authors.lastname: Lewis
authors.forename: Nathan
authors.initials: N
authors.lastname: Ford
authors.forename: Jennifer
authors.initials: J
authors.lastname: Zeinecker
authors.forename: Catherine
authors.initials: C
authors.lastname: Orrell
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lawn
authors.forename: Linda-Gail
authors.initials: LG
authors.lastname: Bekker
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D011320:Primary Health Care; D012307:Risk Factors; D013019:South Africa; D028761:Withholding Treatment / Q000706:statistics & numerical data / Q000639:trends*
chemical_list: D019380:Anti-HIV Agents
references.citation: Trop Med Int Health. 2009 Jul;14(7):713-21
references.pmid: 19497082
references.citation: PLoS One. 2008 Mar 05;3(3):e1725
references.pmid: 18320045
references.citation: PLoS Med. 2007 Oct 16;4(10):e298
references.pmid: 17941716
references.citation: J Acquir Immune Defic Syndr. 2009 Jul 1;51 Suppl 3:S106-10
references.pmid: 19553777
references.citation: J Acquir Immune Defic Syndr. 2006 Aug 15;42(5):554-61
references.pmid: 16868497
references.citation: Curr Opin HIV AIDS. 2010 Jan;5(1):78-82
references.pmid: 20046151
references.citation: PLoS One. 2008 Jul 30;3(7):e2783
references.pmid: 18665246
references.citation: AIDS Res Ther. 2007 Nov 21;4:26
references.pmid: 18031583
references.citation: Trop Med Int Health. 2009 Jan;14(1):36-43
references.pmid: 19017309
references.citation: HIV Med. 2007 Mar;8(2):96-104
references.pmid: 17352766
references.citation: Trop Med Int Health. 2009 Jul;14(7):722-31
references.pmid: 19413745
references.citation: BMC Public Health. 2009 Aug 11;9:290
references.pmid: 19671185
references.citation: BMC Public Health. 2007 Apr 25;7:63
references.pmid: 17459154
references.citation: J Acquir Immune Defic Syndr. 2004 Nov 1;37(3):1351-7
references.pmid: 15483464
references.citation: Am J Respir Crit Care Med. 2007 Jan 1;175(1):87-93
references.pmid: 16973982
references.citation: Trans R Soc Trop Med Hyg. 2009 Jun;103(6):588-93
references.pmid: 19012940
references.citation: PLoS One. 2009 Jun 04;4(6):e5790
references.pmid: 19495419
references.citation: AIDS. 2003 Jan 3;17(1):126-8
references.pmid: 12478080
references.citation: J Acquir Immune Defic Syndr. 2005 Apr 1;38(4):407-16
references.pmid: 15764957
references.citation: Lancet. 2009 Jan 3;373(9657):48-57
references.pmid: 19038438
references.citation: N Engl J Med. 2006 Nov 30;355(22):2283-96
references.pmid: 17135583
references.citation: Bull World Health Organ. 2008 Jul;86(7):559-67
references.pmid: 18670668
references.citation: Trop Med Int Health. 2007 May;12(5):687-94
references.pmid: 17445136
references.citation: J Infect. 2007 Nov;55(5):464-9
references.pmid: 17714788
references.citation: AIDS. 2007 May 11;21(8):965-71
references.pmid: 17457090
references.citation: BMC Public Health. 2008 Feb 18;8:63
references.pmid: 18282286
references.citation: AIDS. 2008 Jan 11;22(2):237-47
references.pmid: 18097226
references.citation: Curr Opin HIV AIDS. 2010 Jan;5(1):70-7
references.pmid: 20046150
references.citation: J Acquir Immune Defic Syndr. 2006 Sep;43(1):78-84
references.pmid: 16878045
references.citation: PLoS Med. 2006 Nov;3(11):e438
references.pmid: 17121449
references.citation: AIDS. 2002 Mar 29;16(5):747-55
references.pmid: 11964531
references.citation: AIDS Rev. 2008 Oct-Dec;10(4):236-44
references.pmid: 19092979
references.citation: AIDS. 2008 Jan 30;22(3):349-56
references.pmid: 18195561
references.citation: AIDS. 2008 Oct 1;22(15):1897-908
references.pmid: 18784453
references.citation: AIDS. 2003 Jun 13;17(9):1369-75
references.pmid: 12799558