 |
|
Staging for Antiretroviral Therapy Among HIV-Infected Drug Users
To the Editor: Highly active antiretroviral therapy (HAART) has been shown to substantially decrease mortality among patients infected with human immunodeficiency virus (HIV).1 However, treatment guidelines have recently supported initiating HAART later in the course of HIV infection. This requires that monitoring of CD4 cell counts be conducted at the time of HIV diagnosis and every 3 months thereafter to ensure treatment is initiated before patients become vulnerable to opportunistic infections.1-2 This may require interventions for populations who may be at risk of poor access to health care.3 We evaluated rates of CD4 cell count monitoring among users of injection drugs having access to free HIV/AIDS care and antiretroviral therapy.4
Methods
In British Columbia, all HIV-positive persons are eligible for HAART free of charge through a province-wide drug treatment program. The Barriers to Access to Antiretroviral Therapy cohort of users of injection drugs in Vancouver has been described previously.4 Participants provided written informed consent prior to enrollment in the study, completed a face-to-face questionnaire, and were provided a stipend of Can $20 at each study visit. The primary outcome was the time to first evaluation of CD4 cell count, ascertained through a linkage with the centralized HIV/AIDS monitoring and treatment registry of British Columbia, which includes all patients in the province.1, 4 Follow-up was completed through time of death or as of May 31, 2003.
The time to first CD4 cell count was evaluated using Kaplan-Meier analysis. Cox proportional hazards regression was used to model the time to first evaluation of the CD4 cell count. Baseline was the date of enrollment into the study for baseline HIV-infected participants, and the estimated date of HIV seroconversion was baseline for participants who became HIV-infected during follow-up.5 The study was approved by the University of British Columbia Research Ethics Board at its St Paul's Hospital site.
Results
Between May 1996 and May 2003, 313 individuals with HIV infection at baseline were recruited and 118 individuals were confirmed as being HIV-infected during follow-up through semiannual HIV serology testing of baseline HIV-negative study participants. As shown in Figure 1, among the 122 participants (39.0%) who had not had a CD4 cell count at baseline and the 107 patients with seroconversion (90.7%) who had not had a CD4 cell count performed at the time they returned to the study site with HIV infection, there were statistically significantly lower CD4 testing rates among women and nonwhite individuals. Although sex and race remained independently associated with the time to first evaluation of CD4 cell count in a fixed Cox model that also adjusted for age and timing of HIV test results, we found that the proportional hazards assumption of the Cox model was violated when we tested the coefficients for time-dependence (P = .01 and P = .45 for sex and race, respectively). Nevertheless, differences between groups persisted over time, with the Kaplan-Meier product-limit cumulative first CD4 cell count testing rate at 18 months being 78.4% for men and 67.3% for women (log-rank P = .03). The cumulative CD4 cell count testing rate at 18 months was 81.7% for white individuals and 65.0% for nonwhite individuals (log-rank P = .009).
|
|
|
|
Figure. Kaplan-Meier Cumulative Rate of First CD4 Cell Count Monitoring Among Injection Drug Users Stratified by Sex and Race
The 18-month period shown approximates a time during which 6 CD4 tests would generally be recommended in human immunodeficiency virus therapeutic guidelines. Because of missing data, 1 person was excluded from the analysis of race.
|
|
|
Comment
In our sample of injection drug users with HIV infection, 39% had not had a CD4 evaluation at the time of enrollment. Women and nonwhites were at highest risk of living with unmonitored HIV infection during follow-up.
A conservative bias in this study is that exposure to HIV testing and counseling and referrals to HIV/AIDS care by study staff likely led to rates of CD4 testing that are substantially increased in comparison to the community at large. We also note that rates of clinical monitoring may be even lower outside of free health care settings.4
Access to Data: Wood had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analyses.
Funding/Support: This study was supported by US National Institutes of Health grant R01 DA011591-04A1 and CIHR grant MOP-67262. Evan Wood and Robert Hogg are supported by the Michael Smith Foundation for Health Research and the Canadian Institutes of Health Research.
Role of the Sponsors: The organizations funding this study had no role in the design and conduct of the study; the collection, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Acknowledgment: We would particularly like to thank the BART participants for their willingness to participate in the study.
Evan Wood, PhD
ewood{at}hivnet.ubc.ca
Department of Medicine
Faculty of Medicine
University of British Columbia
Vancouver
Robert S. Hogg, PhD
Department of Health Care and Epidemiology
Faculty of Medicine
University of British Columbia
Simon Bonner, MSc;
Thomas Kerr, PhD;
Kathy Li, MSc
BC Centre for Excellence in HIV/AIDS
St Paul's Hospital
Vancouver
Anita Palepu, MD, FRCPC;
Silvia Guillemi, MD, FRCPC
Department of Medicine
Faculty of Medicine
University of British Columbia
Martin T. Schechter, MD, PhD
Department of Health Care and Epidemiology
Julio S. G. Montaner, MD, FRCPC
Department of Medicine
Faculty of Medicine
University of British Columbia
1. Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JS. Effect of medication adherence on survival of HIV-infected adults who start highly active antiretroviral therapy when the CD4+ cell count is 0.200 to 0.350 x 10(9) cells/L. Ann Intern Med. 2003;139:810-816.
FREE FULL TEXT
2. Yeni PG, Hammer SM, Carpenter CC, et al. Antiretroviral treatment for adult HIV infection in 2002: updated recommendations of the International AIDS Society-USA Panel. JAMA. 2002;288:222-235.
FREE FULL TEXT
3. Celentano DD, Galai N, Sethi AK, et al. Time to initiating highly active antiretroviral therapy among HIV-infected injection drug users. AIDS. 2001;15:1707-1715.
FULL TEXT
|
ISI
| PUBMED
4. Strathdee SA, Palepu A, Cornelisse PG, et al. Barriers to use of free antiretroviral therapy in injection drug users. JAMA. 1998;280:547-549.
FREE FULL TEXT
5. Tyndall MW, Currie S, Spittal P, et al. Intensive injection cocaine use as the primary risk factor in the Vancouver HIV-1 epidemic. AIDS. 2003;17:887-893.
FULL TEXT
|
ISI
| PUBMED
Letters Section Editor: Robert M. Golub, MD, Senior Editor.
JAMA. 2004;292:1175-1177.
|
