title: [Comparison of three methods to calculate adherence in patients receiving antiretroviral treatment].
abstract: BACKGROUND
  Knowledge of the patient's adherence to antiretroviral treatment is extremely useful for monitoring HIV infection. Several methods have been proposed to calculate adherence, but they all have certain problems at application. The aim of this study was to compare three of the available methods for assessing medication adherence in order to determine their accuracy for this purpose.
  
  
  METHODS
  Three methods for evaluating medication adherence were prospectively studied: 1. Remaining pill count (RPC), 2. Structured interview (SI), and 3. Pharmacy registry of drug refills (DR). The RPC was considered the gold standard and sensitivity and specificity of the other methods was calculated according to the RPC. The study included 100 consecutive patients and had a follow-up of one year.
  
  
  RESULTS
  We were able to assess all three methods in 69 cases. The percentages of patients taking 95% or more of the prescribed dose according to the three methods were 72.5% (RPC), 85.5% (SI) and 81.2% (DR). Taking the RPC as gold standard, there was 75.1% concordance with the DR and 75.1% with the SI method. The sensitivities of the DM and SI were 52.6 % and 42.1 %, respectively. After one year of follow-up, patients with > 90% adherence (RPC) had a 1.29-times higher probability of achieving good virological response (CI 95% 1.04-1.62, p 5 0.0138).
  
  
  CONCLUSIONS
  Although concordance among the methods was acceptable, the SI and DR overestimated adherence as compared to the RPC. Since there is currently no ideal method for determining treatment adherence, it is important to combine several methods to minimize errors and provide results that are as close to the true situation as possible.
authors.affiliation: Servicio de Farmacia. Hospital Clinic de Barcelona. Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Codina
authors.forename: Mireia
authors.initials: M
authors.lastname: Martínez
authors.forename: Montserrat
authors.initials: M
authors.lastname: Tuset
authors.forename: Elena
authors.initials: E
authors.lastname: del Cacho
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Martín
authors.forename: José M
authors.initials: JM
authors.lastname: Miró
authors.forename: Josep
authors.initials: J
authors.lastname: Mallolas
authors.forename: Elisa
authors.initials: E
authors.lastname: de Lazzari
authors.forename: Felipe
authors.initials: F
authors.lastname: García
authors.forename: Esteban
authors.initials: E
authors.lastname: Martínez
authors.forename: José M
authors.initials: JM
authors.lastname: Gatell
authors.forename: Josep
authors.initials: J
authors.lastname: Ribas
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data*; D010352:Patient Dropouts / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D016312:Treatment Refusal / Q000706:statistics & numerical data*
chemical_list: D019380:Anti-HIV Agents