title: CD4 count at antiretroviral therapy initiation and the risk of loss to follow-up: results from a multicentre cohort study.
abstract: Antiretroviral therapy (ART) initiation is now recommended irrespective of CD4 count. However data on the relationship between CD4 count at ART initiation and loss to follow-up (LTFU) are limited and conflicting.
  
  
  
  We conducted a cohort analysis including all adults initiating ART (2008-2012) at three public sector sites in South Africa. LTFU was defined as no visit in the 6 months before database closure. The Kaplan-Meier estimator and Cox's proportional hazards models examined the relationship between CD4 count at ART initiation and 24-month LTFU. Final models were adjusted for demographics, year of ART initiation, programme expansion and corrected for unascertained mortality.
  
  
  
  Among 17 038 patients, the median CD4 at initiation increased from 119 (IQR 54-180) in 2008 to 257 (IQR 175-318) in 2012. In unadjusted models, observed LTFU was associated with both CD4 counts <100 cells/μL and CD4 counts ≥300 cells/μL. After adjustment, patients with CD4 counts ≥300 cells/μL were 1.35 (95% CI 1.12 to 1.63) times as likely to be LTFU after 24 months compared to those with a CD4 150-199 cells/μL. This increased risk for patients with CD4 counts ≥300 cells/μL was largest in the first 3 months on treatment. Correction for unascertained deaths attenuated the association between CD4 counts <100 cells/μL and LTFU while the association between CD4 counts ≥300 cells/μL and LTFU persisted.
  
  
  
  Patients initiating ART at higher CD4 counts may be at increased risk for LTFU. With programmes initiating patients at higher CD4 counts, models of ART delivery need to be reoriented to support long-term retention.
authors.affiliation: Division of Epidemiology and Biostatistics, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Anna
authors.initials: A
authors.lastname: Grimsrud
authors.affiliation: Division of Epidemiology and Biostatistics, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Morna
authors.initials: M
authors.lastname: Cornell
authors.affiliation: Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Michael
authors.initials: M
authors.lastname: Schomaker
authors.affiliation: Center for Global Health & Development, Boston University, Boston, Massachusetts, USA Department of Internal Medicine, Faculty of Health Sciences, Health Economics and Epidemiology Research Office, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, South Africa Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Fox
authors.affiliation: Faculty of Health Sciences, Desmond Tutu HIV Centre, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Catherine
authors.initials: C
authors.lastname: Orrell
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Stellenbosch, Cape Town, South Africa Tygerberg Academic Hospital, Cape Town, South Africa.
authors.forename: Hans
authors.initials: H
authors.lastname: Prozesky
authors.affiliation: Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa Médecins Sans Frontières, Cape Town, South Africa.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Stinson
authors.affiliation: Africa Centre for Health and Population Studies, University of KwaZulu-Natal, Mtubatuba, South Africa.
authors.forename: Frank
authors.initials: F
authors.lastname: Tanser
authors.affiliation: Division of International and Environmental Health, Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
authors.affiliation: Division of Epidemiology and Biostatistics, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Landon
authors.initials: L
authors.lastname: Myer
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003266:Continuity of Patient Care; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D059012:Lost to Follow-Up; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012306:Risk; D013019:South Africa / Q000453:epidemiology; D016896:Treatment Outcome; D019562:Viral Load / Q000187:drug effects
chemical_list: D044966:Anti-Retroviral Agents
keywords: EPIDEMIOLOGY; HIV; INTERNATIONAL HLTH; LONGITUDINAL STUDIES