title: Validation of indirect tuberculosis treatment adherence measures in a resource-constrained setting.
abstract: METHODS
  Arusha, Mwanza, Mufindi and Kilosa in Tanzania.
  
  
  OBJECTIVE
  To assess the test characteristics of three indirect adherence measures against a gold standard of direct measurements of drug intake for use in a resource-constrained setting.
  
  
  METHODS
  We assessed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), and the diagnostic odds ratio (dORs) of three indirect adherence measurement tools against direct measurement in urine using the IsoScreen assay.
  
  
  RESULTS
  The single adherence question of missed doses in the last 2 days had the highest dOR (40.3) compared to the Morisky medication adherence scale (MMAS, 2.5) and pill counts (3.4). The sensitivities of these measures were respectively 97.9%, 92% and 89.6%. Specificity ranged from 46.4% (adherence question) to 17.9% (MMAS). The PPVs of adherence question, pill counts and MMAS were respectively 97.6%, 96.5% and 94.2%, while the NPVs ranged from 50% (adherence question) to 3.1% (MMAS).
  
  
  CONCLUSIONS
  Among several instruments for indirect adherence measure in the routine setting of the Tanzanian National Tuberculosis and Leprosy Programme, a single adherence question was found to have the best discriminatory power. However, the single adherence question might not adequately identify patients who are non-adherent. Confirmatory studies are needed, especially in settings with low adherence rates.
authors.affiliation: <label>*</label>Ifakara Health Institute, Dar es Salaam.
authors.forename: A
authors.initials: A
authors.lastname: Mkopi
authors.affiliation: <label><sup>†</sup></label>National Institute for Medical Research, Dar es Salaam.
authors.forename: N
authors.initials: N
authors.lastname: Range
authors.affiliation: <label><sup>‡</sup></label>National Tuberculosis and Leprosy Programme, Ministry of Health and Social Welfare, Dar es Salaam, United Republic of Tanzania.
authors.forename: F
authors.initials: F
authors.lastname: Lwilla
authors.affiliation: <label><sup>‡</sup></label>National Tuberculosis and Leprosy Programme, Ministry of Health and Social Welfare, Dar es Salaam, United Republic of Tanzania.
authors.forename: S
authors.initials: S
authors.lastname: Egwaga
authors.affiliation: <label><sup>§</sup></label>Novartis Foundation for Sustainable Development, Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Schulze
authors.affiliation: <label>*</label>Ifakara Health Institute, Dar es Salaam.
authors.forename: E
authors.initials: E
authors.lastname: Geubbels
authors.affiliation: <label><sup>¶</sup></label>Department of Global Health, Academic Medical Centre, University of Amsterdam, Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: van Leth
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013636:Tanzania; D014376:Tuberculosis / Q000188:drug therapy*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents