title: Differences between self-reported and electronically monitored adherence among patients receiving antiretroviral therapy in a resource-limited setting.
abstract: BACKGROUND
  Measurement of adherence to antiretroviral therapy (ART) by patient self-report is common in resource-limited settings but widely believed to overstate actual adherence. The extent to which these measures overstate adherence has not been examined among a large patient population.
  
  
  METHODS
  HIV-infected adult patients in Kenya who initiated ART within the past 3 months were followed for 6 months. Adherence was measured by participants' self-reports of doses missed in the past 7 days during monthly clinic visits and by continuous Medication Event Monitoring System (MEMS) in participants' pill bottles. Seven-day self-reported adherence was compared to 7-day MEMS adherence, 30-day MEMS adherence, and adherence more than 90% during each of the first 6 months.
  
  
  RESULTS
  Self-reported and MEMS adherence measures were linked for 669 participants. Mean 7-day self-reported adherence was 98.7% and mean 7-day MEMS adherence was 86.0%, a difference of 12.7% (P < 0.01). The difference between the two adherence measures increased over time due to a decline in 7-day MEMS adherence. However, patients with lower MEMS adherence were in fact more likely to self-report missed doses and the difference between self-reported and MEMS adherence was similar for each number of self-reported missed doses. When analysis was limited to patients who reported rarely or never removing multiple doses at the same time, mean difference was 10.5% (P < 0.01).
  
  
  CONCLUSIONS
  There is a sizable and significant difference between self-reported and MEMS adherence. However, a strong relationship between the measures suggests that self-reported adherence is informative for clinical monitoring and program evaluation.
authors.affiliation: Department of Health Policy and Management, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, 27599-7411, USA. harsha@unc.edu
authors.forename: Harsha
authors.initials: H
authors.lastname: Thirumurthy
authors.forename: Nalyn
authors.initials: N
authors.lastname: Siripong
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Vreeman
authors.forename: Cristian
authors.initials: C
authors.lastname: Pop-Eleches
authors.forename: James P
authors.initials: JP
authors.lastname: Habyarimana
authors.forename: John E
authors.initials: JE
authors.lastname: Sidle
authors.forename: Abraham M
authors.initials: AM
authors.lastname: Siika
authors.forename: David R
authors.initials: DR
authors.lastname: Bangsberg
mesh_terms: D000328:Adult; D055615:Electrical Equipment and Supplies; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D008297:Male; D018670:Monitoring, Ambulatory / Q000379:methods; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D019562:Viral Load; D016903:Drug Monitoring