title: The combination of pill count and self-reported adherence is a strong predictor of first-line ART failure for adults in South Africa.
abstract: BACKGROUND
  Suboptimal adherence to antiretroviral therapy (ART) is a strong predictor of virologic failure (VF) among people with HIV. Various methods such as patient self-report, pill counts and pharmacy refills have been utilized to monitor adherence. However, there are limited data on the accuracy of combining methods to better predict VF in routine clinical settings. We examined various methods to assess adherence including pill count, medication possession ratio (MPR), and self-reported adherence in order to determine which was most highly associated with VF after > 6 months on ART.
  
  
  METHODS
  We conducted a secondary analysis of data from a case-control study. At enrollment, pharmacy refill data were collected retrospectively from the medical chart, pill counts were completed to derive a pill count adherence ratio (PCAR) and a self-report questionnaire was administered to all participants. Parametric smooth splines and receiver operator characteristic (ROC) analyses were carried out to assess the accuracy of the adherence methods.
  
  
  RESULTS
  458 patients were enrolled from October 2010 to June 2012. Of these, 158 (34.50%) experienced VF (cases) and 300 (65.50%) were controls. The median (IQR) PCAR was 1.10 (0.99-1.14) for cases and 1.13 (1.08-1.18) for controls (p < 0.0001). The median MPR was 1.00 (0.97-1.07) for cases and 1.03 (0.96-1.07) for controls (p = 0.83). Combination of PCAR and self-reported questions was highly associated with VF.
  
  
  CONCLUSIONS
  In this setting, a combination of pill count adherence and self-report adherence questions had the highest diagnostic accuracy for VF. Further validation of this simple, low-cost combination is warranted in large prospective studies.
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.forename: Brent A
authors.initials: BA
authors.lastname: Johnson
authors.forename: Jean B
authors.initials: JB
authors.lastname: Nachega
authors.forename: Baohua
authors.initials: B
authors.lastname: Wu
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Ordonez
authors.forename: Anna Q
authors.initials: AQ
authors.lastname: Hare
authors.forename: Rachel
authors.initials: R
authors.lastname: Kearns
authors.forename: Richard
authors.initials: R
authors.lastname: Murphy
authors.forename: Henry
authors.initials: H
authors.lastname: Sunpath
authors.affiliation: 341 Ponce de Leon Avenue, Atlanta, GA, 30308, USA. vcmarco@emory.edu.
authors.forename: Vincent C
authors.initials: VC
authors.lastname: Marconi
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D023241:Antiretroviral Therapy, Highly Active; D016022:Case-Control Studies; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D057566:Self Report; D013019:South Africa; D011795:Surveys and Questionnaires; D017211:Treatment Failure; D019562:Viral Load; D016903:Drug Monitoring
chemical_list: D019380:Anti-HIV Agents