John K. Watters

Targeted Sampling: Options for the Study of Hidden Populations

This paper describes some of the efforts of an interdisciplinary research team investigating the transmission of human immunodeficiency virus (HIV), the causative pathogen associated with the acquired immunodeficiency syndrome (AIDS) and related conditions. The risk groups studied were injecting drug users and their sexual partners. Due to the clandestine nature of illicit drug use, we were faced with two interrelated problems: developing a scientific method to monitor the spread of the HIV infection among these drug users and their sexual partners, groups generally thought to be especially difficult to reach; and creating a health education intervention that would help stop the epidemic from spreading among this population and through them to other members of the community. The method we developed to sample injecting drug users is called targeted sampling. Although it incorporates some aspects of other well established sampling strategies, it is sufficiently different to be treated as a separate research method. Further, targeted sampling provides a cohesive set of research methods that can help researchers study health or social problems that exist among populations that are difficult to reach because of their attributed social stigma, legal status, and consequent lack of visibility.

Validity of self-reported drug use among injection drug users and crack cocaine users recruited through street outreach

This paper examines the validity of self-reported drug use as a measure of behavior change for the evaluation of drug use prevention and HIV risk reduction programs. The results of urinalysis are used to evaluate responses from 154 subjects from 4 cities to questions about drug use in the past 48 hours in the National Institute on Drug Abuses (NIDA) Risk Behavior Assessment (RBA). This instrument is currently being used in 21 studies throughout the United States. Unlike criminal justice or employment settings where there is a tendency to underreport drug use, participants in this research study acted more like a treatment seeking population and were slightly more likely to report drug use than to be tested positive. Urinalysis and self-reports agreed for 86.3% of the subjects who reported use of some form of cocaine (Kappa = .658) and 84.9% of the heroin users (Kappa = .631). The percentage of subjects reporting drug use and testing negative was somewhat higher than the percentage reporting no use and testing positive for both cocaine (7.8% vs. 5.8%) and heroin (9.7% vs. 5.2%). The results suggest that self-reported drug use in not-in-treatment, noninstitutionalized populations is accurate enough for measuring changes in risk behavior practices. Urinalysis may not be necessary if respondents are asked about their drug use in a nonthreatening manner, and if they are assured of the confidentiality of their results.

HIV risk-related sex behaviors among injection drug users, crack smokers, and injection drug users who smoke crack.

OBJECTIVES This study was designed to assess and compare sex risk behaviors for human immunodeficiency virus (HIV) transmission of three drug user groups: injectors who do not smoke crack, crack smokers who do not inject, and injectors who also smoke crack. METHODS Sexual risk behaviors for HIV were assessed among 246 drug users from Denver, Miami, and San Francisco. Respondents were classified into the three drug groups based on self-report and verified through urinalysis and physical inspection. RESULTS An increased risk for HIV through sexual transmission was associated with crack cocaine use, particularly among those who also injected. Crack smoking injectors were more likely to report sex with an injector, exchanging sex for drugs and/or money, drug use before or during sex, and unprotected sexual intercourse. They also injected more than injectors only, smoked crack as often as smokers only, and reported higher overall frequencies of drug use. CONCLUSIONS These findings, together with the higher rates of gonorrhea and syphilis reported by smokers and injectors/smokers, are indicators of the risk crack poses for the heterosexual transmission of HIV.

Suicidal behavior and sexual/physical abuse among street youth

OBJECTIVE To examine the relationship between home life risk factors and suicide attempts among homeless and runaway street youth recruited from both shelters and street locations in Denver, CO; New York City; and San Francisco, CA. METHOD Street youth 12-19 years old (N = 775) were recruited by street outreach staff in Denver, New York City and San Francisco in 1992 and 1993 and interviewed. Cross-sectional, retrospective data were analyzed to examine the relationship between suicide attempts and antecedent home life variables. Logistic regression was used to identify factors predicting suicide attempts. RESULTS Forty-eight percent of the females and 27% of the males had attempted suicide. The mean number of suicide attempts was 6.2 (SD = 12.9) for females and 5.1 for males (SD = 7.6). Among females, 70% reported sexual abuse and 35% reported physical abuse. Among males, 24% reported sexual abuse and 35% reported physical abuse. Sexual and physical abuse before leaving home were independent predictors of suicide attempts for females and males. Other home life factors hypothesized to be risk factors for suicide attempts were not significant. Interaction terms were not significant. Among street youth who were sexually or physically abused in this sample, the odds of attempting suicide were 1.9 to 4.3 times the odds of attempting suicide among those not sexually or physically abused. CONCLUSIONS Interventions attempting to reduce risky behaviors in this population must include assessments of suicidal behaviors as well as components for assisting youth in dealing with the behavioral and emotional sequelae of physical and sexual abuse.

HIV seroprevalence among street-recruited injection drug and crack cocaine users in 16 US municipalities.

OBJECTIVES This study deter- mined human immunodeficiency virus (HIV) seroprevalence and factors associated with HIV infection among street-recruited injection drug users and crack cocaine smokers. METHODS An analysis was performed on HIV serologies and risk behaviors of 6402 injection drug users and 3383 crack smokers in 16 US municipalities in 1992 and 1993. RESULTS HIV seroprevalence was 12.7% among injection drug users and 7.5% among crack smokers. Most high-seroprevalence municipalities (>25%) were located along the eastern seaboard of the United States. In high-seroprevalence municipalities, but not in others, HIV seroprevalence was higher for injection drug users than for crack smokers. Among injection drug users, cocaine injection, use of speedballs (cocaine or amphetamines with heroin), and sexual risk behaviors were independently associated with HIV infection. Among crack smokers, sexual risk behaviors were associated with HIV infection. CONCLUSIONS Injection drug users and crack smokers are at high risk for HIV infection.

Prevalence of sexual risk behaviour and substance use among runaway and homeless adolescents in San Francisco, Denver and New York City:

Summary: We aim to assess the prevalence of HIV sexual risk behaviours and substance use among runaway and homeless adolescents in San Francisco, Denver and New York City. Survey data were examined from 775 runaway and homeless adolescents recruited from street settings and youth agencies during 1992/1993. Nearly all (98%) reported having engaged in sexual intercourse, of whom 49% first had intercourse by the age of 13. Condom use during all vaginal intercourse in the previous 3 months was reported by 42%. Among males, 23% indicated that they had exchanged sex for money, as did 14% of the females. Ninety-seven per cent had used alcohol or drugs and 21% had injected drugs. Overall, 75% reported having had sex while under the influence of alcohol or drugs. Systematic epidemiological studies of this population and the development of innovative interventions are essential to reduce the threat of HIV among runaway and homeless youth.

Impact of law enforcement on syringe exchange programs: A look at Oakland and San Francisco

Drug paraphernalia and prescription laws make syringe exchange programs (SEPs) illegal in most states in the U.S. Nonetheless, SEPs have been started in 25 states and the District of Columbia as of September 1995. In some states like California and New Jersey, SEPs have operated despite police arrest of volunteers and clients. We examine the impact of police action and threat on SEPs by comparing an underground syringe exchange site (SES) in West Oakland to a tolerated SES in the Fillmore neighborhood of San Francisco. The following data sources are utilized: demographic and service utilization data from Alameda County Exchange (ACE) in West Oakland and Prevention Point Needle and Syringe Exchange (PPNSE) in the Fillmore, San Francisco; demographic and syringe exchange utilization information collected from street-recruited samples of injection drug users (IDUs) in West Oakland and the Fillmore; and participant observation of SES in these two communities. We found that police action and the threat of police action in West Oakland decreased utilization of SEP by IDUs, limited the number and diversity of volunteers at SES, and inhibited the operation and expansion of SEP.

Trends in risk behavior and HIV seroprevalence in heterosexual injection drug users in San Francisco, 1986-1992

SummaryWe examine changes and stability in risk behaviors and HIV-1 seroprevalence among heterosexual injection drug users (IDUs) over 13 cross-sectional surveys, 1986–1992. Interviews (n = 5,956) were conducted with IDUs in street settings and drug detoxification clinics over 6.5 years, and respondents were tested for HIV-1 antibody. Trends in use of condoms and bleach and HIV seroprevalence were assessed using multiple logistic and linear regression analyses. The percentage of time condoms were reportedly used during intercourse among men increased from 4.5% to 31.0%. Among the declining population of IDUs who reported needle sharing, reported use of bleach increased from 3% to 89%. Significant changes in use of bleach 100% of the time were reported: 29.8% in 1988, 52.8% in 1990, and 40.0% in 1992. HIV seroprevalence doubled from 7% in 1986 to 14% in 1987. Post-1987 fluctuations in HIV seroprevalence were not significant. Significant changes in risk behaviors among IDUs were reported over the study period. These changes coincided with the implementation of HIV prevention in San Francisco, including outreach programs, HIV testing and counseling, bleach distribution, and syringe exchange. The moderate and stable rate of HIV seroprevalence beginning in 1987 parallels self-reported reductions in risk behavior.

AIDS prevention for intravenous drug users in the community: street-based education and risk behavior.

Conducted a study of behavior change associated with a street-based AIDS education project targeted to intravenous (IV) drug users in San Francisco. Two cross-sections were sampled from drug detoxification clinics and street locations in 1986 (n = 438) and 1987 (n = 623). Significant increases were reported in the percentage of IV drug users who used bleach to decontaminate syringes, who did not share needles in past year, and in condom use. A significant reduction in an index of the number of needle-sharing partners was reported. Respondents ranked treatment program as most important source of AIDS information prior to implementation of the program, and ranked outreach workers as most important after implementation. Findings suggest that this community-based outreach program had at least some impact on knowledge about AIDS and may have led to reductions in behaviors known to transmit HIV.

Prevention of HIV Infection in Street-Recruited Injection Drug Users

Background: Injection drug users (IDUs) and their sex partners account for an increasing proportion of new AIDS and HIV cases in the United States, but public debate and policy regarding the effectiveness of various HIV prevention programs for them must cite data from other countries, from non‐street‐recruited IDUs already in treatment, or other programs, and from infection rates for pathogens other than HIV. Methods: Participants were recruited from the street at six sites (Baltimore [Maryland], New York [two sites], Chicago [Illinois], San Jose [California], Los Angeles [California], and at a state womens correctional facility [Connecticut]), interviewed with a standard questionnaire, and located and reinterviewed at one or more follow‐up visits (mean, 7.8 months later). HIV serostatus and participation in various programs and behaviors that could reduce HIV infection risk were determined at each visit. Results: In all, 3773 participants were recruited from the street, and 2306 (61%) were located and interviewed subsequently. Of 3562 initial serum specimens, 520 (14.6%) were HIV‐seropositive; at subsequent assessment, 19 people, all from the East Coast and Chicago, had acquired HIV. Not using previously used needles was substantially protective against HIV acquisition (relative risk [RR], 0.29; 95% confidence interval [CI], 0.11‐0.80 ) and, in a multivariate model, was significantly associated with use of needle and syringe exchange programs (adjusted odds ratio [ORadj], 2.08; 95% CI, 1.15‐3.85). Similarly, reduction of injection frequency was very protective against seroconversion (RR, 0.33; 95% CI, 0.14‐0.80), and this behavior was strongly associated with participation in drug treatment programs (ORadj, 3.54; 95% CI, 2.50‐5.00). In a separate analysis, only 37.5% of study‐participants had sufficient new needles to meet their monthly demand. Conclusions: In this large multicity study of IDUs in the United States, several HIV prevention strategies appeared to be individually and partially effective; these results indicate the continued need for, and substantial gaps in, effective approaches to preventing HIV infection in drug users.