Biomedical subjects

D Vlahov

Publications and source records attributed to D Vlahov.

At least 271 records · Page 15Linked to original sources

PubMed1992

Characteristics of intravenous drug users by history of arrest and treatment for drug use.

Typically, intravenous drug users are studied by drawing samples from drug treatment programs, from the criminal justice system, or by outreach into the street community via anthropological or ethnographic methods. Among 1405 subjects recruited through extensive community outreach, 46% reported no history of treatment for drug abuse and 16% said they had not been arrested in the preceding 10 years; 130 (9%) reported neither history. A history of arrest was higher among men and those with a history of: treatment for drug abuse, low educational attainment, having received public assistance, and unemployment. A history of drug treatment was higher among women and those of an older age with a history of: arrest, having received public assistance, and a greater duration and intensity of intravenous drug use. Intravenous drug users who had neither a history of arrest since 1977 nor of drug treatment were more likely to be women and more educated, to have not received public assistance, and to inject less than weekly. These data indicate that characteristics of intravenous drug users differ by history of arrest and treatment, substantiating reports of heterogeneity among intravenous drug users.

Black or African American↗

PubMed1992

Correlates of human immunodeficiency virus infection in intravenous drug users: are treatment-program samples misleading?

Using a community-based sample of 1632 intravenous drug users in Baltimore, Maryland, USA, this study evaluated a possible selection bias faced when studying risk factors for human immunodeficiency virus, type 1 (HIV-1) in intravenous drug users drawn solely from treatment programs. Consenting subjects, recruited by extensive distribution of brochures and word-of-mouth, underwent confidential interviews about drug use behaviors in a setting that was independent of community service agencies. Of 1632 subjects, 275 (17%) were currently enrolled in treatment programs. These subjects were similar in many respects to those not currently in treatment, including HIV-1 seroprevalence; however, they differed in that those not in treatment were more likely to be male, younger and black than those currently in treatment, and to have started injecting drugs more recently. However, associations between HIV-1 seropositivity and a series of demographic and drug-using characteristics were mostly similar in direction and magnitude among subjects currently in treatment and those not in treatment. These results suggest that one-time samples of drug users enrolled in treatment programs do not necessarily present a misleading picture of correlates of HIV-1 seropositivity.

Adult↗

PubMed1992

Measurement of HIV risk behaviors among intravenous drug users.

This paper reviews issues related to the measurement of drug use and other behaviors in studies of human immunodeficiency virus (HIV) infection in intravenous drug users. These issues include: (1) choice of variables, (2) study design, (3) time frame of measurement, (4) categories of measurement, (5) interviewer effects, and (6) validity of measurement. Difficulties and approaches for measuring drug use and other intimate behaviors in intravenous drug users are discussed. Attempts to come to terms with these measurement issues in the context of HIV infection in intravenous drug users should lead to the further development of methods for use in the general context of drug abuse research.

HIV Infections↗

PubMed1992

HIV-1 infection and intravenous drug use: longitudinal neuropsychological evaluation of asymptomatic subjects.

A previous baseline cross-sectional comparison of cognitive performance of a group of AIDS-free, HIV-seropositive intravenous drug users with seronegative control intravenous drug users revealed no significant differences attributable to HIV. We now present longitudinal follow-up results from the same cohort of 160 intravenous drug users. There were no differences in performance by serostatus group at either 6- or 12-month follow-up visits, although differences by age and education were observed. Improvement in performance secondary to practice effects was comparable in both serostatus groups. These findings confirm that chronic intravenous drug use may be associated with a wide range of neuropsychological deficits, but there is no evidence that such preexisting deficits interact with HIV infection to produce additional cognitive impairment in otherwise asymptomatic intravenous drug users. Together with results from other high-risk groups such as homosexual/bisexual men and hemophiliacs, these results confirm that neurocognitive abnormalities during the presymptomatic stages of HIV infection are rare, regardless of the route of acquisition of the virus.

Adult↗

PubMed1992

Terminology for drug injection practices among intravenous drug users in Baltimore.

Terms for four discrete drug injection practices were obtained by presenting photographs and a brief description of practices to intravenous drug users who enrolled in a longitudinal study of HIV infection in Baltimore. The 2,921 respondents were predominantly male (81%) and Black (90%), the median age was 34 years (range: 18-68 years), and the median duration of intravenous drug use was 13 years (range 0-50 years). Forty-six different terms were used to characterize direct injection into a vein, 51 for the practice of repeatedly withdrawing and reinjecting one's own blood following injection of drug, 39 for subcutaneous injection, and 45 for transferring drug between different syringes. Terms tended to cluster by race and duration of drug use. These data indicate substantial variation in terminology for drug injection practices. Further, they augment prior research showing that photographs may be used as a useful aid in survey research on drug experiences in the population.

Adolescent↗

PubMed1992

Needle-cleaning practices among intravenous drug users who share injection equipment in Baltimore, Maryland.

In Baltimore, Maryland, between 1988 and 1989, 2,921 intravenous drug users were recruited into a study of drug injection practices and human immunodeficiency virus (HIV) infection. Sixty-three percent reported both current use and sharing of needles; almost all these (N = 1,757) reported using injection equipment immediately after it was used by another intravenous drug user. Of the 1,757, 62% said that they "typically" cleaned the used equipment with bleach or alcohol before injecting. These data suggest that information about disinfecting needles has disseminated into this population and identifies several groups to target for interventions.

Adult↗

PubMed1992

Immune serum markers and CD4 cell counts in HIV-infected intravenous drug users.

We examined the association of three serum immune markers with CD4 cell counts in a large cohort of i.v. drug users with and without human immunodeficiency virus (HIV) infection. Levels of beta 2-microglobulin and neopterin were significantly elevated in HIV-infected subjects and increased in association with decline in CD4 cell counts (all p less than 0.001). Serum IgA levels in HIV-seropositive individuals were significantly elevated only when the CD4 cell count was less than 200/microliters (p less than 0.001). After controlling for HIV status and CD4 count, recent history of hepatitis was associated with significantly higher beta 2-microglobulin (p = 0.028) and marginally higher neopterin (p = 0.052) levels. There was no association of race, gender, or drug use patterns with levels of serum immune markers after controlling for HIV status and CD4 count. These data indicate that immune activation is coupled with immunosuppression in HIV-infected i.v. drug users. In addition, beta 2-microglobulin and neopterin levels are elevated in persons with a recent history of hepatitis but not in those with recent non-AIDS-defining bacterial infections. Markers of immune activation do not vary by race, gender, or drug use patterns among i.v. drug users.

Biomarkers↗

PubMed1992

Prognostic indicators for development of AIDS among intravenous drug users.

A cohort of 544 human immunodeficiency virus-1 (HIV-1) seropositive intravenous drug users (IVDUs) was recruited in 1988 and early 1989; data on laboratory markers, clinical symptoms, intravenous drug use, and demographics were collected. Forty-one IVDUs developed AIDS within 2 years of enrollment. Data were analyzed using methods of survival analysis. None of the individuals reported use of antiviral agents or Pneumocystis carinii prophylaxis at baseline. A very strong (p less than 0.001) dose-response relationship was identified between CD4 cell count at baseline and the subsequent development of AIDS. In multivariate analysis, both the presence of more than one clinical HIV-1-related symptom and serum neopterin greater than 12 nmol/L showed significant associations with the relative hazard (95% confidence interval) of AIDS after controlling for CD4 of 2.9 (1.6, 5.6) and 2.0 (1.0, 3.7), respectively. In these IVDUs, serum beta 2-microglobulin did not add predictive power for progression to AIDS. The effect of clinical symptoms was stronger for high CD4 cell counts, indicating the need to monitor HIV seropositive IVDUs with both laboratory studies and clinical evaluation.

Acquired Immunodeficiency Syndrome↗

PubMed1992

HIV-1 infection in the correctional setting.

The correctional setting provides an opportunity to serve IV drug users who might otherwise be difficult to access. Interventions--including education, counseling, treatment for HIV-1 infection, and treatment for drug abuse--conducted in the correctional setting could have benefits for individual inmates and the surrounding community.

HIV Infections↗

PubMed1991

Antibody responses to Haemophilus influenzae type B vaccines in men with human immunodeficiency virus infection.

BACKGROUND: Persons with human immunodeficiency virus (HIV) infection are at increased risk for serious infections caused by Haemophilus influenzae, yet there are few data on their antibody responses to the H. influenzae type b vaccines. METHODS: We evaluated antibody responses in 248 men who were randomly assigned to receive a single dose of either the H. influenzae type b polysaccharide (PRP) vaccine or the polysaccharide-mutant diphtheria toxoid conjugate vaccine (PRP-CRM). The subjects were stratified into four groups: seronegative men (67 subjects), men with asymptomatic HIV infection (79), men with symptomatic HIV infection (47), and men with the acquired immunodeficiency syndrome (AIDS) (55). RESULTS: Before immunization, the subjects with AIDS had the lowest PRP-antibody titers; 40 percent had titers below the putative protective level (less than 0.15 micrograms per milliliter). In the seronegative subjects, those with asymptomatic HIV infection, and those with symptomatic HIV infection, the PRP-CRM vaccine led to a threefold greater increase in geometric mean antibody titers than did the PRP vaccine (P less than 0.01). However, the subjects with AIDS had a greater antibody response to the PRP vaccine. The antibody response of HIV-seropositive men to the PRP-CRM vaccine correlated significantly with the number of CD4 lymphocytes (r = 0.47, P less than 0.0001, as compared with r = -0.01 for the PRP vaccine). In these HIV-infected men, both vaccines elicited the dominant anti-PRP idiotype described previously in populations not infected with HIV. CONCLUSIONS: Immunization with the PRP-CRM conjugate vaccine early in the course of HIV infection is likely to confer protection against disease caused by H. influenzae type b.

AIDS Vaccines↗

PubMed1991

New evidence on intravenous cocaine use and the risk of infection with human immunodeficiency virus type 1.

To examine whether recent intravenous use of cocaine might be associated with increased risk of human immunodeficiency virus type 1 (HIV) infection, the authors studied 2,597 active intravenous drug users: 2,399 with recent cocaine injection and 198 with recent injection of heroin or other drugs but not cocaine. These subjects were adult residents of Baltimore City and the surrounding Maryland counties, recruited via outreach into the community between February 1988 and March 1989. In contrast to the first report on the cocaine-HIV association, the present study sample was not recruited solely from drug treatment programs. In the present study, estimated HIV seroprevalence was 26.4% for recent cocaine injectors as compared with 10.6% among all other recent intravenous drug users; the relative odds estimate was 3.03. In the untreated segment of the sample, HIV seroprevalence was 26.0% for recent cocaine injectors as compared with 8.9% among others (relative odds (RO) = 3.61). The estimated degree of association did not change appreciably when multiple logistic regression was used to hold constant potentially confounding and/or mediating variables such as receptive anal intercourse, number of sex partners, and use of injection equipment obtained at shooting galleries (RO = 2.64). Augmenting these cross-sectional data, preliminary prospective data showed excess risk of HIV seroconversion among recent cocaine injectors (estimated relative risk = 2.11). While other research has examined the cocaine-HIV association, the present study differs in that it has allowed a test for whether the association was a spurious artifact of studying drug users recruited solely from drug treatment programs, a broad array of alternative determinants of HIV infection have been held constant, and the association has been examined with seroconversion data. The results lend support to the abiding concern about the risk of HIV infection among cocaine users.

Adolescent↗

PubMed1991

Antibody to hepatitis C virus among cardiac surgery patients, homosexual men, and intravenous drug users in Baltimore, Maryland.

In order to define the risk factors for infection with hepatitis C virus, the authors determined the prevalence and incidence of antibodies to hepatitis C in three cohorts in Baltimore, Maryland, enrolled in prospective studies of human immunodeficiency virus (HIV-1) infection. Among 500 multi-transfused patients who underwent cardiac surgery in 1985 and 1986, 12 (2.4%) were hepatitis C seropositive before surgery while 19 (3.9%) developed antibodies in the 8-12 months after surgery. The seroprevalence of hepatitis C virus among 225 intravenous drug users followed since 1988 was 85%, which did not vary by HIV-1 status. Longer duration of intravenous drug use was significantly associated with hepatitis C seropositivity. Among 926 homosexual/bisexual men followed since 1984, 15 (1.6%) were hepatitis C seropositive; only intravenous drug use and a history of hepatitis A were marginally associated with hepatitis C in this population. No association was found between hepatitis C virus and HIV-1 or sexual behavior variables in this population. These data suggest that hepatitis C is readily transmitted by blood exposure, but is transmitted inefficiently by sexual means.

Adult↗

PubMed1991

Prevalence of antibody to HIV-1 among entrants to US correctional facilities.

Prevalence of antibody to the human immunodeficiency virus type 1 (HIV-1) was assessed among 10,994 consecutive male and female entrants to 10 correctional systems in the United States. The HIV-1 seroprevalence for the 10 systems ranged from 2.1% to 7.6% for men and 2.5% to 14.7% for women; seroprevalence among women was higher than among men across nine of 10 systems. Using age 25 years to divide the population, HIV-1 prevalence among young women (5.2%) was significantly higher than among young men (2.3%), but similar to that in both older women (5.3%) and older men (5.6%). Overall, HIV-1 rates for nonwhites (4.8%) were higher than those for whites (2.5%). Although categories were identified across correctional systems, which may serve to focus prevention programs, variability in rates among correctional systems indicates that program planning must take local conditions into consideration.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Sexually transmitted diseases in a population of intravenous drug users: association with seropositivity to the human immunodeficiency virus (HIV).

The association between human immunodeficiency virus (HIV) seropositivity and a history of sexually transmitted diseases (STDs), evidence of STDs on physical examination, and sexual and drug use practices was studied in a population of 2921 intravenous drug users (IVDUs) in Baltimore during 1988 and 1989. Overall, 24.1% were HIV-seropositive at baseline, and 60% reported a history of an STD. A significant association was found between HIV seropositivity and a history of syphilis (P = .04); both were more frequent among homosexual/bisexual men than among heterosexual IVDUs. In multivariate analysis, a history of syphilis was independently associated with HIV seroprevalence in homosexual/bisexual male IVDUs, of whom 90% reported a history of sexual intercourse with women. Cocaine injection was independently associated with HIV seropositivity but not a history of syphilis on multivariate analysis. STDs, indicative of unsafe sex practices, are common in this population; efforts are needed to prevent sexual transmission of HIV infection among IVDUs and their sex partners.

Baltimore↗

PubMed1991

HIV seroconversion and disinfection of injection equipment among intravenous drug users, Baltimore, Maryland.

To examine the putative protective effect of disinfectant use on HIV seroconversion among intravenous drug users, we conducted a nested case-control study comparing 22 black heterosexual HIV seroconverters with 95 persistent seronegatives matched on gender, use of cocaine, date of study entry, and duration of follow-up. For intravenous drug users who reported using disinfectant all the time, the odds of seroconversion was 0.77 (95% CI: 0.25-2.38) compared with those who reported no use of disinfectants; for those who used disinfectants some of the time, the corresponding odds ratio was 0.91 (95% CI: 0.26-3.31). The odds ratio for use of disinfectant all the time was 0.63 (95% CI: 0.10-3.91) for those injecting at galleries and 1.08 (95% CI: 0.35-3.11) for those not injecting at galleries. These data suggest a limited protective effect of disinfectant use in the field which may be more beneficial to those injecting in shooting galleries.

Adult↗

PubMed1991

HIV-1 infection and nervous system abnormalities among a cohort of intravenous drug users.

A group of 109 HIV seropositive and 51 seronegative intravenous drug users was evaluated for the presence of HIV-1-related neurologic disease using clinical, neurologic, neuropsychological, and electrophysiologic evaluations. About 80% of HIV seropositive subjects had less than two constitutional symptoms. CD4 cell counts were less than 500/mm3 among 56% of seropositive participants; three individuals were receiving zidovudine. Neurologic abnormalities were found frequently among the cohort, independently of HIV-1 serostatus; electrophysiologic abnormalities were uncommon. Participants from both serologic groups scored significantly lower on neuropsychological tests as compared with norms established for a cohort of homosexual men, and there was no clear association between HIV-1 serostatus and performance on these tests. This study suggests that HIV infection was not the dominant cause of neurologic abnormalities among the study cohort.

Adult↗

PubMed1991

Utilization of health services in a cohort of intravenous drug users with known HIV-1 serostatus.

BACKGROUND: Intravenous drug users (IVDUs) with human immunodeficiency virus (HIV) infection and AIDS often have no health insurance or rely on public programs to finance their health care. We examined the independent contributions of HIV serostatus, clinical symptoms, CD4 cell counts, and health insurance to utilization of health services among 1881 intravenous drug users in Baltimore, Maryland. METHODS: Participants in an ongoing natural history study of HIV were informed of HIV serostatus and seropositives were informed of CD4 cell counts; 6 months later, participants were administered a questionnaire concerning self-reported use of health services, insurance coverage, and HIV-related symptoms. RESULTS: Of 1881 participants, 67% had health insurance (including Medicaid), 48% had at least one outpatient visit, and 12% had at least one inpatient visit within the prior 6 months. The proportion of the study population that was HIV-1 seropositive was 32%. In multivariate analysis, the single most important predictor of health care utilization was the presence of two or more HIV-related clinical symptoms. HIV positive serostatus alone or known low CD4 counts were not significantly associated with use of health care services. CONCLUSIONS: These data suggest that HIV seropositive IVDUs are not receiving recommended preventive care. Additional efforts will be needed to ensure that HIV-seropositive drug users participate in currently recommended protocols for early treatment of asymptomatic HIV-1 infection.

Adult↗

PubMed1991

Risk factors for shooting gallery use and cessation among intravenous drug users.

BACKGROUND: Shooting galleries, locations where intravenous drug users (IVDUs) can rent or borrow needles and syringes, are a high-risk environment for HIV-1 transmission. This study investigates risk factors for lifetime attendance at shooting galleries and differentiates characteristics of those who continue to frequent shooting galleries and those who have stopped. METHODS: We interviewed 2615 active IVDUs in Baltimore in 1988 and 1989 and determined patterns of IV drug use, sociodemographics, and HIV-1 serostatus as related to persistence vs cessation of shooting gallery use. RESULTS: Over half (52%) of active IVDUs reported ever using a shooting gallery, with 33% reporting use within the prior 3 months. In multivariate analysis, lifetime shooting gallery use was associated with male gender, homosexuality/bisexuality, low socioeconomic status, Black race, and heavier drug involvement. Persistent shooting gallery users were more frequently male, homosexual/bisexual, homeless, less educated, and started IV drug use more recently compared with those who ceased going to shooting galleries. CONCLUSIONS: Shooting gallery attendance may be pragmatic from a sociological and economic perspective, but it carries with it a heightened risk of acquiring HIV-1 infection.

Adult↗