title: Association of antiretroviral therapy adherence and health care costs.
abstract: BACKGROUND
  Antiretroviral therapy (ART) adherence predicts HIV disease progression and survival, but its effect on direct health care costs is unclear.
  
  
  OBJECTIVE
  To determine the effect of ART adherence on direct health care costs among adults in a resource-limited setting.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Aid for AIDS, a private-sector disease management program in South Africa.
  
  
  METHODS
  6833 HIV-infected adults who started ART between 6 August 2000 and 30 April 2006.
  
  
  METHODS
  Monthly direct health care costs authorized by Aid for AIDS were averaged over all months. Pharmacy claim adherence, expressed as a percentage, was categorized into quartiles, from 1 (lowest) to 4 (highest). Effects of covariates on monthly total costs were assessed with a 2-step model with logit for probability of nonzero costs and a generalized linear model (GLM).
  
  
  RESULTS
  Total mean monthly costs were $370 (SD, $644). Mean monthly costs of ART were $32 (SD, $18); hospitalizations, $151 (SD, $436); consultations, $76 (SD, $66); investigations, $37 (SD, $50); and non-ART medications, $53 (SD, $180). Total mean monthly costs ranged from $313 (SD, $598) for quartile 4 to $376 (SD, $657) for quartile 1. Hospitalization costs increased from 29% to 51% of total costs as adherence decreased. In the GLM 2-step model, moving from adherence quartile 1 to quartile 2, 3, or 4 increased the probability of having nonzero total monthly costs by 0.078, 0.15, and 0.21 percentage point, respectively (P < 0.001). For patients with nonzero costs, increasing adherence from quartile 1 to quartile 2, 3, or 4 decreased total monthly costs by $70, $133, and $192, respectively (P < 0.001). Moving from adherence quartiles 1 to 4 had the highest decrease in net overall median monthly health care costs (-$85 [interquartile range, -$116 to -$41]).
  
  
  CONCLUSIONS
  Indirect health care costs were not included. Experience may not reflect that of public HIV/AIDS programs.
  
  
  CONCLUSIONS
  High ART adherence was associated with lower mean monthly direct health care costs, particularly reduced hospitalization costs, in this South African HIV cohort.
authors.affiliation: Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA. jnachega@hsph.harvard.edu
authors.forename: Jean B
authors.initials: JB
authors.lastname: Nachega
authors.forename: Rory
authors.initials: R
authors.lastname: Leisegang
authors.forename: David
authors.initials: D
authors.lastname: Bishai
authors.forename: Hoang
authors.initials: H
authors.lastname: Nguyen
authors.forename: Michael
authors.initials: M
authors.lastname: Hislop
authors.forename: Susan
authors.initials: S
authors.lastname: Cleary
authors.forename: Leon
authors.initials: L
authors.lastname: Regensberg
authors.forename: Gary
authors.initials: G
authors.lastname: Maartens
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy / Q000191:economics; D000328:Adult; D019380:Anti-HIV Agents / Q000191:economics* / Q000627:therapeutic use*; D003627:Data Interpretation, Statistical; D004180:Direct Service Costs; D016527:Drug Costs; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000191:economics*; D017048:Health Care Costs; D006760:Hospitalization / Q000191:economics; D006801:Humans; D008297:Male; D055118:Medication Adherence
chemical_list: D019380:Anti-HIV Agents