title: Adherence to and effectiveness of highly active antiretroviral treatment for HIV infection: assessing the bidirectional relationship.
abstract: BACKGROUND
  It is well established that high adherence to HIV-infected patients on highly active antiretroviral treatment (HAART) is a major determinant of virological and immunologic success. Furthermore, psychosocial research has identified a wide range of adherence factors including patients' subjective beliefs about the effectiveness of HAART. Current statistical approaches, mainly based on the separate identification either of factors associated with treatment effectiveness or of those associated with adherence, fail to properly explore the true relationship between adherence and treatment effectiveness. Adherence behavior may be influenced not only by perceived benefits-which are usually the focus of related studies-but also by objective treatment benefits reflected in biological outcomes.
  
  
  METHODS
  Our objective was to assess the bidirectional relationship between adherence and response to treatment among patients enrolled in the ANRS CO8 APROCO-COPILOTE study. We compared a conventional statistical approach based on the separate estimations of an adherence and an effectiveness equation to an econometric approach using a 2-equation simultaneous system based on the same 2 equations.
  
  
  RESULTS
  Our results highlight a reciprocal relationship between adherence and treatment effectiveness. After controlling for endogeneity, adherence was positively associated with treatment effectiveness. Furthermore, CD4 count gain after baseline was found to have a positive significant effect on adherence at each observation period. This immunologic parameter was not significant when the adherence equation was estimated separately. In the 2-equation model, the covariances between disturbances of both equations were found to be significant, thus confirming the statistical appropriacy of studying adherence and treatment effectiveness jointly.
  
  
  CONCLUSIONS
  Our results, which suggest that positive biological results arising as a result of high adherence levels, in turn reinforce continued adherence and strengthen the argument that patients who do not experience rapid improvement in their immunologic and clinical statuses after HAART initiation should be prioritized when developing adherence support interventions. Furthermore, they invalidate the hypothesis that HAART leads to "false reassurance" among HIV-infected patients.
authors.affiliation: ESSEC Business School, Avenue Bernard Hirsch, B.P.50105, 95021 Cergy, France. lamiraud@essec.edu
authors.forename: Karine
authors.initials: K
authors.lastname: Lamiraud
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Moatti
authors.forename: François
authors.initials: F
authors.lastname: Raffi
authors.forename: Maria-Patrizia
authors.initials: MP
authors.lastname: Carrieri
authors.forename: Camelia
authors.initials: C
authors.lastname: Protopopescu
authors.forename: Christian
authors.initials: C
authors.lastname: Michelet
authors.forename: Luminita
authors.initials: L
authors.lastname: Schneider
authors.forename: Fideline
authors.initials: F
authors.lastname: Collin
authors.forename: Catherine
authors.initials: C
authors.lastname: Leport
authors.forename: Bruno
authors.initials: B
authors.lastname: Spire
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology; D023241:Antiretroviral Therapy, Highly Active / Q000523:psychology* / Q000706:statistics & numerical data; D001294:Attitude to Health; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D003863:Depression / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D055118:Medication Adherence / Q000523:psychology*; D008875:Middle Aged; D018803:Models, Economic; D012959:Socioeconomic Factors; D016896:Treatment Outcome; D016903:Drug Monitoring