title: Not all are lost: interrupted laboratory monitoring, early death, and loss to follow-up (LTFU) in a large South African treatment program.
abstract: BACKGROUND
  Many HIV treatment programs in resource-limited settings are plagued by high rates of loss to follow-up (LTFU). Most studies have not distinguished between those who briefly interrupt, but return to care, and those more chronically lost to follow-up.
  
  
  METHODS
  We conducted a retrospective cohort study of 11,397 adults initiating antiretroviral therapy (ART) in 71 Southern African Catholic Bishops Conference/Catholic Relief Services HIV treatment clinics between January 2004 and December 2008. We distinguished among patients with early death, within the first 7 months on ART; patients with interruptions in laboratory monitoring (ILM), defined as missing visits in the first 7 months on ART, but returning to care by 12 months; and those LTFU, defined as missing all follow-up visits in the first 12 months on ART. We used multilevel logistic regression models to determine patient and clinic-level characteristics associated with these outcomes.
  
  
  RESULTS
  In the first year on ART, 60% of patients remained in care, 30% missed laboratory visits, and 10% suffered early death. Of the 3,194 patients who missed laboratory visits, 40% had ILM, resuming care by 12 months. After 12 months on ART, patients with ILM had a 30% increase in detectable viremia compared to those who remained in care. Risk of LTFU decreased with increasing enrollment year, and was lowest for patients who enrolled in 2008 compared to 2004 [OR 0.49, 95%CI 0.39-0.62].
  
  
  CONCLUSIONS
  In a large community-based cohort in South Africa, nearly 30% of patients miss follow-up visits for CD4 monitoring in the first year after starting ART. Of those, 40% have ILM but return to clinic with worse virologic outcomes than those who remain in care. The risk of chronic LTFU decreased with enrollment year. As ART availability increases, interruptions in care may become more common, and should be accounted for in addressing program LTFU.
authors.affiliation: Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America. aahonkhai@partners.org
authors.forename: Aima A
authors.initials: AA
authors.lastname: Ahonkhai
authors.forename: Farzad
authors.initials: F
authors.lastname: Noubary
authors.forename: Alison
authors.initials: A
authors.lastname: Munro
authors.forename: Ruth
authors.initials: R
authors.lastname: Stark
authors.forename: Marisa
authors.initials: M
authors.lastname: Wilke
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Freedberg
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
authors.forename: Elena
authors.initials: E
authors.lastname: Losina
mesh_terms: D023241:Antiretroviral Therapy, Highly Active / Q000706:statistics & numerical data; D015331:Cohort Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D059012:Lost to Follow-Up; D010349:Patient Compliance / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013019:South Africa / Q000453:epidemiology