Injection Drug Use and Crack Cocaine Smoking: Independent and Dual Risk Behaviors for HIV Infection
Total Page:16
File Type:pdf, Size:1020Kb
Injection Drug Use and Crack Cocaine Smoking: Independent and Dual Risk Behaviors for HIV Infection CLYDE B. MCCOY, PHD, SHENGHAN LAI, MD, PHD, LISA R. METSCH, PHD, SARAH E. MESSIAH, MPH, AND WEI ZHAO, MD, MS PURPOSE: Previous studies have examined the practices of injecting drugs or smoking crack cocaine as high-risk, but independent, factors for HIV transmission. To explore the independent and dual risks of injection practices and crack smoking, this study examined HIV seroprevalence rates among distinct drug user groups, based on patterns of daily administration. METHODS: A sample of 3555 drug users and neighborhood controls in urban Miami, FL and rural Belle Glade and Immokalee, FL were partitioned into four mutually-exclusive groups: 1) injection drug users (IDUs); 2) crack-cocaine smokers; 3) dual users who both smoked crack and injected drugs; and 4) non–drug-user controls. RESULTS: HIV seroprevalence rates were 45.1% for IDUs, 30.5% for dual users, 20.1% for crack smokers and 7.3% for controls. Multivariate logistic regression analysis found that when compared with controls odds ratios for HIV seropositivity were 9.81 for IDUs, 5.27 for dual users, and 2.24 for crack smokers. CONCLUSIONS: These findings provide evidence of: 1) behavioral and structural co-factors that influence HIV exposure patterns among drug users; and 2) the substantially higher risk of HIV infection among IDUs compared with other drug users. Intervention strategies must be tailored for the specific drug use subpopulations to optimize efficacy. Ann Epidemiol 2004;14:535–542. ą 2004 Elsevier Inc. All rights reserved. KEY WORDS: Injection Drug Users, HIV Infection, Crack Cocaine. as clear in terms of how or why certain subpopulations INTRODUCTION within the IDU group such as multi-drug users may contrib- As the HIV/AIDS epidemic enters its third decade in the ute to the epidemic. Despite findings reporting that IDUs United States, research has shown that illicit drug users and crack cocaine smokers share social networks, norms, continue to fuel the epidemic due to high risk drug use and and risk behaviors (38, 39), few studies have considered the sexual practices, accounting for over one quarter of the interplay of drug injection and crack smoking for those who nation’s total AIDS cases (1). In the year 2000, 42,156 engage in both forms of drug use and their subsequent rela- new cases of AIDS were reported (1), 28% of which were tionship to HIV transmission and seroprevalence (7, 32, injection drug user (IDU)-related, due to both high-risk 40, 41). In one of the only recent studies that has considered injection and sex practices (2–28). Non-injection drug use this interaction, a lower rate of HIV infection was found in (such as crack-cocaine and heroin sniffing) also contributes dual users of crack and injection drugs compared with IDUs to the spread of the epidemic through risky sexual behav- who did not smoke crack, despite a higher prevalence of iors such as trading sex for drugs and/or money or having self-reported sexual risk behaviors (32). However, this study sex with an HIV-infected drug user (1, 7, 29–37). did not include a non-drug using control group. The authors, Although injection drug use is clearly a high-risk behav- as well as others (41), have suggested that crack-smoking ior for HIV infection, the epidemiological literature is not injectors may comprise a subgroup with distinctive drug use patterns and unique social network characteristics. Further investigation is needed to clarify the intersection of drug injection and crack smoking in relation to HIV From the Comprehensive Drug Research Center, Department of Epide- seropositivity to address the gaps in basic behavioral and miology and Public Health, University of Miami School of Medicine, Miami, Florida (C.B.M., L.R.M., S.E.M., W.Z.); and Johns Hopkins Uni- social processes that contribute to HIV risk (42). Therefore, versity, Baltimore, Maryland (S.L.). the present study compares HIV seroprevalence among Address correspondence to: Clyde B. McCoy, Ph.D., Department of four mutually-exclusive drug-user groups: 1) current injec- Epidemiology and Public Health, University of Miami School of Medicine, 1801 NW 9th Avenue, Miami, Florida 33136. Tel.: (305) 243-6005; Fax: tors who did not smoke crack, 2) current crack cocaine (305) 243-3353. E-mail: [email protected] smokers who did not inject, 3) dual users who both currently This research was supported by the National Institute on Drug Abuse, smoked crack and injected drugs, and 4) a baseline compari- grants DARO107694, DARO109953, and the University of Miami Drug Abuse and AIDS Research Center (DA P3013870). son group of neighborhood controls who neither smoked Received July 11, 2003; accepted October 8, 2003. crack nor injected drugs. ą 2004 Elsevier Inc. All rights reserved. 1047-2797/04/$–see front matter 360 Park Avenue South, New York, NY 10010 doi:10.1016/j.annepidem.2003.10.001 536 McCoy et al. AEP Vol. 14, No. 8 DRUG USE AND HIV RISK BEHAVIORS September 2004: 535–542 were used to recruit their drug user counterparts, and shared METHODS similar demographic and social characteristics as a result. Data for this analysis were obtained from the University of To determine whether drug type was independently re- Miami Community AIDS Research and Evaluation Studies lated to HIV seropositivity, additional demographic and (Miami CARES) conducted between 1988 and 1994 in risk behavior variables traditionally associated with HIV urban Miami, Florida and two rural communities, Belle seropositivity (7, 29, 32) were analyzed. Univariate logistic Glade and Immokalee, also located in South Florida (43– regression analysis was used to evaluate the relationship 46). More specifically, Belle Glade is a small, rural, agricul- between each independent variable and HIV seropositivity. tural community located at the southern tip of Lake Okee- Cross-tabulations of risk behaviors by drug use group and chobee in Palm Beach County, approximately 50 miles stepwise multivariate logistic regression analysis were per- north of Miami. Immokalee is a rural, migrant agricultural formed to quantify the association between drug use and community located in Collier County, approximately 150 HIV seropositivity. Finally, a stepwise comparison of each drug type group vs. the control group was performed to miles Northwest of Miami. Both Belle Glade and Immokalee determine what, and how much, risk behaviors were being have a permanent population of approximately 18,000, and conducted by each group. are supplemented by migrant workers who winter in the area, picking vegetables and fruits. Outreach workers recruited participants from street venues, housing projects, public RESULTS transport, and other public areas not associated with medical care, drug treatment, or the criminal justice system. Eligible Outreach workers recruited 3555 participants: 2465 from participants were at least 18 years of age, had not been in Miami, 254 from Belle Glade, and 836 from Immokalee. Demographic characteristics and respective HIV status drug treatment for 30 days prior to assessment, and reported are presented in Table 1. Overall, 62.9% of the sample current drug use (defined as drug use in the last 30 days). Interviews were conducted by trained interviewers at a TABLE 1. Demographic characteristics and HIV seropositivity free-standing community assessment center in the respective of study participants (N ϭ 3555) areas. Respondents were encouraged to participate through N%HIVϩ (%) the use of small monetary incentives and by written assur- ance of anonymity and confidentiality. Study site Miami 2465 69.4 26.6 After agreeing to participate and signing a consent state- Belle Glade 254 7.1 23.6 ment, study participants were administered a standardized Immokalee 836 23.5 8.4 HIV risk assessment instrument and provided with pre-test Gender counseling. Certified phlebotomists collected blood samples Male 2235 62.9 19.5 Female 1320 37.1 26.5 for HIV serotesting. HIV seropositivity was defined as a Ethnicity* repeatedly reactive ELISA with Protein gel blot confir- African American 2558 72.0 26.5 mation and was performed by local licensed laboratories. Hispanic 613 17.3 9.1 Verification of self-reported drug use among both the IDU Non-Hispanic White 343 9.7 12.5 Age* and non-IDU drug user groups was confirmed by urinalysis 18–24 393 11.1 16.0 with the ONTRAK toxicological screen kits from Roche 25–44 2721 77.0 24.0 Diagnostic Laboratories for opiates, cocaine, and marijuana 45ϩ 422 11.9 16.1 and direct examination for physical track marks. Non-IDUs Education* Ͻ were also examined for tracks marks to contend with any High school 2017 56.8 22.4 Ͼ High school 1534 43.2 21.7 possible detection bias. Employment* Study participants were members of one of the following Full-time 406 11.4 15.5 mutually-exclusive drug-user groups: 1) current injectors Part-time 1102 31.0 18.0 who did not smoke crack, 2) current crack cocaine smok- Unemployed 2045 57.6 25.0 Lives alone ers who did not inject, 3) dual users who both currently No 2535 71.3 22.2 smoked crack and injected drugs, and 4) a baseline compari- Yes 1020 28.7 21.8 son group of neighborhood controls who neither smoked Children living with you crack nor injected drugs. Although the baseline comparison No 2980 83.8 21.9 Yes 575 16.2 23.0 group included individuals who neither smoked crack nor Street homeless injected drugs, in some cases there was alcohol and/or mari- No 3119 87.7 22.1 juana use reported. The control group was recruited from Yes 436 12.3 21.8 the same geographic locales, by the identical methods that *Does not add up to 3555 due to missing value.