title: Age in antiretroviral therapy programmes in South Africa: a retrospective, multicentre, observational cohort study.
abstract: BACKGROUND
  As access to antiretroviral therapy (ART) expands, increasing numbers of older patients will start treatment and need specialised long-term care. However, the effect of age in ART programmes in resource-constrained settings is poorly understood. The HIV epidemic is ageing rapidly and South Africa has one of the highest HIV population prevalences worldwide. We explored the effect of age on mortality of patients on ART in South Africa and whether this effect is mediated by baseline immunological status.
  
  
  METHODS
  In this retrospective cohort analysis, we studied HIV-positive patients aged 16-80 years who started ART for the first time in six large South African cohorts of the International Epidemiologic Databases to Evaluate AIDS-Southern Africa collaboration, in KwaZulu-Natal, Gauteng, and Western Cape (two primary care clinics, three hospitals, and a large rural cohort). The primary outcome was mortality. We ascertained patients' vital status through linkage to the National Population Register. We used inverse probability weighting to correct mortality for loss to follow-up. We estimated mortality using Cox's proportional hazards and competing risks regression. We tested the interaction between baseline CD4 cell count and age.
  
  
  RESULTS
  Between Jan 1, 2004, and Dec 31, 2013, 84,078 eligible adults started ART. Of these, we followed up 83,566 patients for 174,640 patient-years. 8% (1817 of 23,258) of patients aged 16-29 years died compared with 19% (93 of 492) of patients aged 65 years or older. The age adjusted mortality hazard ratio was 2·52 (95% CI 2·01-3·17) for people aged 65 years or older compared with those 16-29 years of age. In patients starting ART with a CD4 count of less than 50 cells per μL, the adjusted mortality hazard ratio was 2·52 (2·04-3·11) for people aged 50 years or older compared with those 16-39 years old. Mortality was highest in patients with CD4 counts of less than 50 cells per μL, and 15% (1103 of 7295) of all patients aged 50 years or older starting ART were in this group. The proportion of patients aged 50 years or older enrolling in ART increased with successive years, from 6% (290 of 4999) in 2004 to 10% (961 of 9657) in 2012-13, comprising 9% of total enrolment (7295 of 83 566). At the end of the study, 6304 (14%) of 44,909 patients still alive and in care were aged 50 years or older.
  
  
  CONCLUSIONS
  Health services need reorientation towards HIV diagnosis and starting of ART in older individuals. Policies are needed for long-term care of older people with HIV.
  
  
  BACKGROUND
  National Institutes of Health (National Institute of Allergy and Infectious Diseases), US Agency for International Development, and South African Centre for Epidemiological Modelling and Analysis.
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa; Division of Epidemiology and Biostatistics, Cape Town, South Africa. Electronic address: morna.cornell@uct.ac.za.
authors.forename: Morna
authors.initials: M
authors.lastname: Cornell
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa.
authors.forename: Leigh F
authors.initials: LF
authors.lastname: Johnson
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa.
authors.forename: Michael
authors.initials: M
authors.lastname: Schomaker
authors.affiliation: Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Wellcome Trust 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: Health Economics and Epidemiology Research Office, Wits Health Consortium, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Mhairi
authors.initials: M
authors.lastname: Maskew
authors.affiliation: School of Public Health and Family Medicine, Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa.
authors.forename: Robin
authors.initials: R
authors.lastname: Wood
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Stellenbosch and Tygerberg Academic Hospital, Tygerberg, Cape Town, South Africa.
authors.forename: Hans
authors.initials: H
authors.lastname: Prozesky
authors.affiliation: McCord Hospital, Durban, South Africa.
authors.forename: Janet
authors.initials: J
authors.lastname: Giddy
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa; Médecins Sans Frontières, Khayelitsha, Cape Town, South Africa.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Stinson
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa; Division of International and Environmental Health, Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa.
authors.forename: Andrew
authors.initials: A
authors.lastname: Boulle
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Cape Town, South Africa; Division of Epidemiology and Biostatistics, Cape Town, South Africa.
authors.forename: Landon
authors.initials: L
authors.lastname: Myer
mesh_terms: D000328:Adult; D000367:Age Factors; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000401:mortality; D006801:Humans; D008297:Male; D020380:Needs Assessment / Q000458:organization & administration; D016730:Program Development; D011634:Public Health; D012189:Retrospective Studies; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents