Predictors of Sharing Injection Equipment by HIV-Seropositive Injection Drug Users

J Acquir Immune Defic Syndr. Author manuscript; available in PMC 2010 May 3.

Published in final edited form as:

J Acquir Immune Defic Syndr. 2008 December 1; 49(4): 447–450.

PMCID: PMC2862654

NIHMSID: NIHMS159639

Predictors of Sharing Injection Equipment by HIV-Seropositive Injection Drug Users

Carl A. Latkin, Ph.D.,¹ Amy S. Buchanan, M.H.S.,² Lisa R. Metsch, Ph.D.,³ Kelly Knight, MEd.,⁴ Mary H. Latka, Ph.D.,⁵ Yuko Mizuno, Ph.D.,⁶ Amy R. Knowlton, Sc.D.,¹ and INSPIRE Team

¹Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD

²Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD

³Department of Epidemiology and Public Health, Leonard M. Miller School of Medicine, University of Miami, Miami, FL

⁴AIDS Research Institute, University of California, San Francisco, CA

⁵Aurum Institute for Health Research, Johannesburg, South Africa

⁶Division of HIV/AIDS Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA.

¹Correspondence concerning this article should be addressed to Carl Latkin, Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, 624 North Broadway, Room 737, Baltimore, MD 21205, U.S.A. Phone (410) 955-3972; fax (410) 955-7241; Email: clatkin/at/jhsph.edu

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Abstract

Among HIV-positive injection drug users (IDUs), we examined baseline predictors of lending needles and syringes, and sharing cookers, cotton, and rinse water in the prior 3 months at follow-up. Participants were enrolled in INSPIRE, a secondary prevention intervention for sexually active HIV-positive IDUs in four US cities during 2001–2005. The analyses involved 357 participants who reported injecting drugs in the prior six months at either the 6- or 12-months follow-up visit. About half (49%) reported at least one sharing episode. In adjusted analyses, peer norms supporting safer injection practices, and having primary HIV medical care visits in the prior 6 months were associated with reporting no sharing of injection equipment. Higher levels of psychological distress was associated with a greater likelihood of reporting drug paraphernalia sharing. These findings suggest that intervention approaches for reducing HIV-seropositive IDUs’ transmission of blood-borne infections should include peer-focused interventions to alter norms of drug paraphernalia sharing and promoting primary HIV care and mental health services.

Injection drug use continues to be a significant source of HIV transmission. Many countries report injection drug use (IDU) as the primary mode of HIV transmission.¹^–³ In some countries, IDUs have reported reductions in syringe sharing; however, many IDUs continue to share syringes despite high levels of HIV knowledge and a higher proportion report sharing other types of injection equipment used in the drug preparation process, such as cookers, cotton, and rinse water.⁴^,⁵ In addition to the health concern of transmitting HIV, a large proportion of injectors, especially HIV positive IDUs, are co-infected with hepatitis C (HCV), which is readily transmitted through the sharing of injection equipment.⁶

Numerous studies have identified correlates of sharing injection equipment,⁷^–¹² including type and frequency of drug use, relationship to injection partners, composition of social networks, availability of clean injection equipment, homelessness, fear of police, and laws and policies governing syringe access. Yet few prospective studies have focused on sharing injection equipment among sexually active HIV seropositive injectors. The current study examined equipment sharing among HIV-seropositive IDUs who were enrolled in the INSPIRE study (2001–05),¹³.

A prior cross-sectional analysis of INSPIRE baseline data examined lending of syringes and needles to partners perceived to be HIV-seronegative or of unknown HIV-serostatus.¹⁴ The multivariate analyses revealed that older IDUs, high school graduates, and those reporting more supportive peer norms for safer injection practices were less likely to report lending syringes. Admission to a hospital for drug treatment in the past 6 months, injecting with more than one person in the past 3 months, and having more psychiatric symptoms, as measured by the Brief Symptom Inventory (BSI), were positively associated with lending syringes. Additional prior cross-sectional studies found that social norms and psychiatric symptoms, especially depressive symptoms, were associated with needle sharing.¹⁵^,¹⁶^,¹⁷ ¹⁸ The present study examined baseline predictors of sharing injection equipment as well as syringes at subsequent 6- and 12-month follow-up assessments among seropositive IDUs. Based on the findings of Metsch et al.¹⁴ it was anticipated that sharing injection equipment would be associated with age, education, drug treatment, injecting with others, peer injection norms, and psychiatric symptoms.

Methods

Study population: Participants were enrolled in the Intervention for Seropositive Injectors- Research and Evaluation (INSPIRE) study, a 10-session secondary HIV prevention intervention conducted in Baltimore, Miami, New York City, and San Francisco (2001–2005). Participants were recruited from clinic and community settings. Eligibility criteria included being at least 18 years of age, confirmed HIV-positive serostatus, self-reported IDU in the prior year, sex with an opposite-sex partner in the prior three months, and willingness to provide oral and blood specimens. Assessments were administered by audio computer-assisted self interview. The CDC and local site IRBs approved the study protocol. A detailed description of the INSPIRE project has been reported elsewhere.⁸ The overall retention rates for randomized participants were 83% and 85% at 6- and 12-months follow-up, respectively, and 91% for either visit.

Measures: Measures were based on the findings of Metsch et al.¹⁴ and on the sampling distributions. Demographic variables included age, biological sex, educational attainment (having at least a high school degree), employment status, and homelessness (squat, homeless shelter, car, or street). Two questions, with a 5-point response option, assessed whether the participant thought that their friends lent needles or shared injection equipment, and two questions assessed whether the participant thought it was important to comply with friends’ expectations about lending needles or sharing injection equipment. A composite score was created from the 4 items. Mental health was assessed by combining 3 subscales (depression, anxiety, and hostility – 18 items) of the BSI (α=.95), which assessed psychiatric symptoms in the prior week.¹⁹ HIV primary health care visits were defined as “a visit to a doctor or medical provider to have a check up on how you’re doing with your HIV or AIDS, (which may include) discussion about HIV or AIDS medications, or blood test results.” Drug abuse treatment was measured by: 1) hospital admission for drug treatment; 2) outpatient drug treatment; and 3) methadone maintenance program attendance. The dependent variable, referred to in this study as “sharing” was defined as self-reported sharing of injection equipment (cookers, cotton, or rinse water) or lending a used syringe to individuals who were HIV-seropositive, HIV-seronegative, or of unknown serostatus at either the 6- or 12-months follow-up.

Missing data: A total of 89 (out of 966) participants did not return for assessments at the 6- or 12-months follow-up. Sensitivity analyses (p < 0.10), revealed that at baseline participants who were lost to follow-up did not differ from participants who were retained on most baseline measures, including study condition, homelessness, recruitment city, health care visits, or drug treatment. Those lost to follow-up were significantly less likely to have a high school education, an annual income below $5,000, younger, employed, male, and inject heroin and cocaine together.

The sample for this analysis (n=357) was restricted to participants who met the study enrollment criteria and reported injecting drugs in the prior 3 months during the 6 or 12-month follow-up assessments. There were 486 participants who reported no injection drug use in the 3 months prior on either follow-up assessment and 44 individuals with missing data who were excluded from the analyses. Participants were categorized as not sharing drug equipment (n=195) if they reported using injection drugs at one or more of the follow-up visits and reported not lending syringes or sharing of cookers, cottons, or rinse water.

Analyses: Bivariate analyses were conducted with logistic regression models. Subsequently, a multivariable logistic regression model was constructed to test which baseline variables were associated with sharing injecting equipment at follow-up. In addition to demographic factors of gender, age, and education, the multivariable model adjusted for recruitment city and study condition. Bivariate tests indicating statistical differences at p < 0.20 were included in multivariate models. Variables no longer significant (p > 0.10) in the multivariable model were removed if the removal did not change the value of the other covariates in the model by more than 10% and were not considered to be theoretically important confounders.

Results

Table 1 presents the number and proportion of participants who shared injection equipment at the follow-up assessments. There was a dramatic drop in self-reported injecting from 84% at baseline to 31% at 12 months follow-up, and equipment sharing reports plummeted from 45% at baseline to 12% at 12 months follow-up. There were 22% who reported injection at both and 45% at one of the follow-ups. Table 2 presents the unadjusted and adjusted associations between baseline factors and drug equipment sharing. Engagement in medical care, as assessed by any primary HIV care services visits and any admission to a hospital for drug treatment in the past 6 months, was significantly associated with not sharing injection equipment. Peer norms supporting safer injection practices was also associated with less sharing. Lower scores on the BSI and current enrollment in methadone maintenance were marginally associated with a lower likelihood of equipment sharing. In the multivariate analyses, which adjusted for recruitment site and study condition, peer norms supporting safer injection practices, having at least one primary HIV medical visit maintained statistically significant associations with reporting no equipment sharing, whereas a higher score on the BSI was associated with a significantly greater likelihood of equipment sharing.

Table 1

Injection drug use and equipment sharing^{^} at baseline, 6- month, and 12-month assessments, the INSPIRE study.

Table 2

Unadjusted and adjusted associations of baseline characteristics with sharing injection equipment in the past 3 months at 6 or 12 month follow-up among those who reported injecting in the 3 months prior to one or more of the follow-up assessments, INSPIRE (more ...)

Discussion

Our findings replicate and expand on the prior cross-sectional study by Metsch et al.¹⁴ We found that baseline measures of peer norms and self-reported psychiatric symptoms, as measured by the BSI, strongly predicted sharing of injection equipment among HIV-seropositive IDUs. One difference from the prior study was that self-reported primary HIV health care visits were found to be associated with significantly less injection equipment sharing but drug abuse treatment was not. It is plausible that those IDUs who received primary HIV care had unmeasured social and economic resources that facilitate access to medical care and enable the regulation of their health behaviors, including sharing of injection equipment. An alternative explanation is that HIV illness may lead to increased health care utilization and reduced injection risk behaviors. However, we did not find that measures of HIV illness (CD4 count < 200) at baseline predicted sharing.

The study findings are subject to the limitations of sampling, attrition, differences in the time periods between assessments and unmeasured key variables, as well as self-reporting biases. Many of the study participants reported that they had stopped injecting and were not include in the analyses. There were also substantially lower levels of self-reported injection risk behaviors at follow-up as compared to baseline. There are several explanations to these finding of risk reduction, including regression toward the mean. The information that all participants received about HIV prevention may have lead to a reduction in sharing of injection equipment and heightened the social desirable response bias to report reduced sharing. These study limitations and changes in patterns of drug use may help to explain differences between our results and previously reported findings.

The findings have implications for HIV prevention efforts among HIV-seropositive IDUs. They underscore the need to promote social norms of not sharing injection equipment. One method of promoting risk reduction social norms is through peer outreach education and social network approaches. The findings of high BSI scores predicting sharing suggest the potential importance of addressing mental health in this population. Future studies need to examine the extent to which mental health treatment for HIV positive IDUs’ may reduce their HIV transmission risk.²⁰ Finally, these data indicate that HIV medical care utilization is linked to injection risk. Future studies should also assess this link to determine if greater engagement in HIV health care may also reduce HIV injection risk behaviors.

ACKNOWLEDGEMENTS

This study was supported by the Centers for Disease Control and Prevention and the Health Resources and Services Administration. The INSPIRE Study Group includes the following people: Baltimore: Carl Latkin, Amy Knowlton, Karin Tobin; Miami: Lisa Metsch, Eduardo Valverde, James Wilkinson, Martina DeVarona; New York: Mary Latka, Dave Vlahov, Phillip Coffin, Marc Gourevitch, Julia Arnsten, Robert Gern; San Francisco: Cynthia Gomez, Kelly Knight, Carol Dawson Rose, Starley Shade, Sonja Mackenzie; Centers for Disease Control and Prevention: David Purcell, Yuko Mizuno, Scott Santibanez, Richard Garfein, Ann O’Leary; Health Resources and Services Administration: Lois Eldred, Kathleen Handley. We would also like to acknowledgements the following people for their contributions to this research: Baltimore: Susan Sherman, Roeina Marvin, Joanne Jenkins, Donald Gann, Tonya Johnson; Miami: Clyde McCoy, Rob Malow, Wei Zhao, Lauren Gooden, Sam Comerford, Virginia Locascio, Curtis Delford, Laurel Hall, Henry Boza, Cheryl Riles; Faye Yeomans; New York: George Fesser, Carol Gerran, Diane Thornton; San Francisco: Caryn Pelegrino, Barbara Garcia, Jeff Moore, Erin Rowley, Debra Allen, Dinah Iglesia-Usog, Gilda Mendez, Paula Lum, Greg Austin; Centers for Disease Control and Prevention: Gladys Ibanez, Hae-Young Kim, Toni McWhorter, Jan Moore, Lynn Paxton, John Williamson; Centers for Disease Control and Prevention (Laboratory): Lee Lam, Jeanne Urban, Stephen Soroka, Zilma Rey, Astrid Ortiz, Sheila Bashirian, Marjorie Hubbard, Karen Tao, Bharat Parekh, Thomas Spira.

Footnotes

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

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