Validity of Self-Reported Antiretroviral Therapy Use Among Injection Drug Users
2006; Lippincott Williams & Wilkins; Volume: 41; Issue: 4 Linguagem: Inglês
10.1097/01.qai.0000199096.11215.79
ISSN1944-7884
AutoresEvan Wood, Thomas Kerr, Robert S. Hogg, Ruth Zhang, Mark Tyndall, Julio Montaner,
Tópico(s)HIV Research and Treatment
ResumoTo the Editor: Improving access to antiretroviral therapy among HIV-infected injection drug users (IDUs) is an urgent international priority,1,2 and several international initiatives, including the World Health Organization's "3 × 5 Initiative,“ are seeking to improve use of antiretroviral therapies among IDUs. At present, a number of prospective cohort studies of IDUs are exploring barriers and facilitators of HIV/AIDS care among IDUs in an effort to inform strategies for improving uptake and adherence to antiretroviral therapy among IDUs.3-5 Rigorous evaluation of the health behaviors of marginalized populations, such as IDUs, may be compromised by the fact that self-reports of IDUs have been shown to be susceptible to socially desirable responding.6 Although this concern primarily relates to socially undesirable behaviors, such as syringe sharing,6 it has also been shown that IDUs may overreport use of HIV prevention services.7 Because the validity of self-reporting of antiretroviral therapy access has not been previously evaluated, the present study was conducted to evaluate the concordance between IDUs' self-reported use of HIV treatment and their actual use as determined by a confidential record linkage with a centralized database that afforded accurate measurement of antiretroviral use. We recruited a random sample of IDUs from an HIV prevention program in Vancouver, Canada through methods described previously.8 All IDUs who were included in the study provided written informed consent, and the study was approved by the University of British Columbia's Research Ethics Board. The local setting is somewhat unique for researching access to HIV/AIDS care, because end points related to the use of antiretroviral therapy can be accurately ascertained through a confidential record linkage with the province's centralized HIV/AIDS monitoring and treatment registry, which includes all HIV-infected patients who have ever had their CD4 cell count tested in the province of British Columbia.3,9 On recruitment into the study, IDUs provided a venous blood sample for testing of HIV serology, and an interviewer-administered questionnaire was conducted by a trained research nurse. For the present study, we examined questions related to the patient's current or former use of antiretroviral therapies for the treatment of HIV infection. We evaluated the concordance between self-reported use of antiretroviral therapy and actual use of antiretroviral therapy by comparing self-reported questionnaire data with each individual's records within the province's centralized HIV/AIDS care registry. Between December 1, 2003 and December 15, 2004, 1003 individuals were recruited into the cohort, among whom 164 were baseline HIV-positive. Overall, 14 HIV-infected individuals reported being HIV-negative or unaware of their HIV status and were not included in subsequent analyses because they were not queried regarding their use of antiretroviral therapy. Overall, among the 150 HIV-infected individuals who were considered, 87 reported having ever been on antiretroviral therapy, among whom 11 (12.6%) had actually never been on antiretroviral therapy based on the database linkage (Table 1). Similarly, among the 63 individuals who reported having never been on antiretrovirals, 17 (27.0%) had actually previously had an antiretroviral therapy prescription filled. In terms of current antiretroviral use, 2 individuals reported being currently on antiretrovirals despite having never been on antiretroviral therapy and 4 individuals who reported not presently being on antiretroviral therapy were currently receiving antiretroviral therapy based on the database linkage. The Cohen κ value for the concordance between self-reported antiretroviral use and actual use was 0.61 (95% confidence interval: 0.48 to 0.74).TABLE 1: Concordance Between Self-Reported and Database-Ascertained Use of Antiretroviral Therapy Among HIV-Infected IDUsThe present study indicates that a large proportion of HIV-infected IDUs misreport their use of antiretroviral therapy. Although a significant proportion of IDUs overreported their use of antiretroviral therapy, almost a third of individuals who reported having never used antiretrovirals had actually been dispensed antiretroviral therapy from one of the province‘s antiretroviral dispensing pharmacies. The present study is limited in that it was not possible to discern the explanations for the discordance between self-reported and actual use of antiretroviral therapy. Nevertheless, these findings raise major methodologic issues for cohort studies using self-reported measures of antiretroviral therapy.4,5,10 ACKNOWLEDGMENTS The authors thank the staff of the InSite safer injecting facility (SIF) and Vancouver Coastal Health (Chris Buchner, Heather Hay, and David Marsh, MD). We also thank Bonnie Devlin, Evelyn King, Aaron Eddie, Peter Vann, Dave Isham, Daniel Kane, Steve Gaspar, Carl Bognar, Megan Oleson, Deborah Graham, and Suzy Coulter for their research and administrative assistance. This study was made possible through a financial contribution from Health Canada. Evan Wood, PhD*† Thomas Kerr, PhD* Robert S. Hogg, PhD* Ruth Zhang, MSc* Mark W. Tyndall, MD, ScD*† Julio S. G. Montaner, MD, FRCPC, FCCP*† *British Columbia Centre for Excellence in HIV/AIDS St. Paul's Hospital Vancouver, British Columbia, Canada and †Department of Infectious Diseases Faculty of Medicine University of British Columbia Vancouver, British Columbia, Canada
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