Needle exchange programs for the prevention of human immunodeficiency virus infection: epidemiology and policy.
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Epidemiologic Methods↗
Biomedical subjects
S A Strathdee
Publications and source records attributed to S A Strathdee.
Sexual and drug risk-related behaviours after initiating highly active antiretroviral therapy among injection drug users.
OBJECTIVE: To assess whether initiation of highly active antiretroviral therapy (HAART) is associated with a subsequent resumption of sexual and drug use risk behaviors. METHODS: Within an ongoing prospective study of HIV-seropositive injection drug users (IDUs), a subsample with at least one CD4 cell count < 500 x 106 cells/l after 1996 (when HAART became available) and three consecutive visits were selected for analysis. Patients underwent semi-annual interviews for risk behaviors and reports of medication use. Data from visits immediately prior to and following initiation of HAART for the treated group, and from consecutive visits for the eligible but untreated group were compared using linear growth curve analysis. RESULTS: Of 316 eligible HIV-seropositive IDUs, 133 reported HAART use during the study period; 95% were African American, 76% were male, and median age at enrollment was 34 years. The proportion who reported any sexual activity increased over time from 55 to 61% for the HAART-treated group, but decreased from 67 to 63% in the untreated group (P = 0.03); the respective values for unprotected sex were 18 versus 20% and 36 versus 28% (P = 0.06). In both treated and untreated groups, the proportion injecting drugs declined (P = 0.04), whereas the proportion reporting needle sharing decreased marginally (P = 0.11). However, trends in use of shooting galleries between the groups differed (P = 0.04) increasing slightly from 2.3 to 3% in the treated group while decreasing from 12 to 5% in the untreated group. CONCLUSION: In persons treated with HAART, self-report of high-risk behaviors remained stable or showed some increase. Persons initiating HAART should be counselled to refrain from high-risk behaviors.
Adult↗
Dynamics of SEN virus infection among injection drug users.
SEN virus (SENV) is a recently discovered group of DNA viruses whose members (SENV-D and SENV-H) are linked to posttransfusion hepatitis. Of 397 injection drug users (IDUs) in Baltimore, Maryland, SENV-D infection was detected by polymerase chain reaction in serum samples from 130 (32.7%) and SENV-H infection in 149 (37.5%). Of 41 IDUs in whom SENV-D DNA was initially detected, retesting for viral persistence a median of 9.3 years later detected SENV-D in 25 (61.0%), whereas SENV-H was detected on retesting in only 14 (26.9%) of 52 IDUs in whom the virus was originally found. Reinfection was apparent (>5% nucleotide difference) in 77.8% of IDUs who repeatedly tested positive for SENV-D DNA and in 55.6% of those who repeatedly tested positive for SENV-H DNA. Among Baltimore IDUs, SENV-D and SENV-H infections are common and dynamic, including both viral clearance and reinfection. The clinical significance of SENV infection in this setting remains unknown.
Adult↗
Incidence of hepatitis C virus infection among injection drug users during an outbreak of HIV infection.
BACKGROUND: Beginning in 1994, Vancouver experienced an explosive outbreak of HIV infection among injection drug users (IDUs). The objectives of this study were to measure the prevalence and incidence of hepatitis C virus (HCV) infection in this context and to examine factors associated with HCV seroconversion among IDUs. METHODS: IDUs recruited through a study site and street outreach completed interviewer-administered questionnaires covering subjects' characteristics, behaviour, health status and service utilization and underwent serologic testing for HIV and HCV at baseline and semiannually thereafter. A Cox proportional hazards model was used to identify independent correlates of HCV seroconversion. RESULTS: As of Nov. 30, 1999, 1345 subjects had been recruited into the study cohort. The prevalence of anti-HCV antibodies was 81.6% (95% confidence interval [CI] 79.6% to 83.6%) at enrollment. Sixty-two HCV seroconversions occurred among 155 IDUs who were initially HCV negative and who returned for follow-up, for an overall incidence density rate of 29.1 per 100 person-years (95% CI 22.3 to 37.3). The HCV incidence remained above 16 per 100 person-years over 3 years of observation (December 1996 to November 1999), whereas HIV incidence declined from more than 19 to less than 5 per 100 person-years. Independent correlates of HCV seroconversion included female sex, cocaine use, injecting at least daily and frequent attendance at a needle exchange program. INTERPRETATION: Because of high transmissibility of HCV among those injecting frequently and using cocaine, the harm reduction initiatives deployed in Vancouver during the study period proved insufficient to eliminate hepatitis C transmission in this population.
Adolescent↗
Longitudinal patterns of sexual behavior and condom use in a cohort of HIV-negative gay and bisexual men in Vancouver, British Columbia, Canada, 1995-2000.
OBJECTIVE: To characterize longitudinal patterns of sexual behavior in a cohort of young gay and bisexual men and determine their reasons for not using condoms. METHODS: Prospective data from a cohort of young gay and bisexual men aged 18 to 30 years were studied. Study participants had completed a baseline questionnaire and HIV test between May 1995 and April 1996 and four annual follow-up questionnaires. RESULTS: A total of 130 HIV-negative Vanguard participants met the eligibility criteria for this analysis. The median age at baseline was 26 years (range, 24-28). Most were white (79%), had completed high school (85%), were currently employed (82%), lived in stable housing (95%), and reported annual incomes of > or =$10,000 (82%). (All dollar amounts are given in Canadian dollars.) Consistently over the 5-year study period, > 70% of study subjects reported having > or =1 regular male sexual partners in the previous year. During each of the five successive 1-year periods, between 34% and 40% of respondents reported having had unprotected receptive anal intercourse with regular partners. Slightly fewer individuals (between 29%-39%) reported having had unprotected insertive anal intercourse with regular partners. Between 13% and 25% of participants reported having had insertive unprotected anal intercourse with casual sexual partners; and between 9% and 18% reported having had unprotected receptive anal intercourse with casual sexual partners. Reasons for engaging in unprotected anal intercourse varied depending on type of sexual partnership. CONCLUSION: High-risk sexual behaviors remained fairly consistent over a 5-year period in this study. This suggests that it is critically important to understand the motivations for unprotected sex when designing and implementing programs aimed at reducing HIV risk among young gay and bisexual men.
Adolescent↗
Time to initiating highly active antiretroviral therapy among HIV-infected injection drug users.
OBJECTIVE: Studies have shown that HIV-infected injection drug users (IDUs) are less likely to receive antiretroviral therapy than non-drug users. We assess factors associated with initiating highly active antiretroviral therapy (HAART) in HIV-infected IDUs. METHODS: A cohort study of IDUs carried out between 1 January 1996 and 30 June 1999 at a community-based study clinic affiliated to the Johns Hopkins University, Baltimore, Maryland. The participants were a total of 528 HIV-infected IDUs eligible for HAART based on CD4+ cell count. The main outcome measure was the time from treatment eligibility to first self-reported HAART use, as defined by the International AIDS Society-USA panel (IAS-USA) guidelines. RESULTS: By 30 June 1999, 58.5% of participants had initiated HAART, most of whom switched from mono- or dual-combination therapy to a HAART regimen. Nearly one-third of treatment-eligible IDUs never received antiretroviral therapy. Cox proportional hazards regression showed that initiating HAART was independently associated with not injecting drugs, methadone treatment among men, having health insurance and a regular source of care, lower CD4+ cell count and a history of antiretroviral therapy. CONCLUSIONS: Self-reported initiation of HAART is steadily increasing among IDUs who are eligible for treatment; however, a large proportion continues to use non-HAART regimens and many remain treatment-naive. Although both groups appear to have lower health care access and utilization, IDUs without a history of antiretroviral therapy use would have more treatment options available to them once they become engaged in HIV care.
Adult↗
Use of audio computer-assisted self-interviews to assess tuberculosis-related risk behaviors.
UNLABELLED: The objective of this study was to compare self-reported tuberculosis and human immunodeficiency virus (HIV) risk factors obtained from computer-assisted questionnaires and interviewer-assisted questionnaires among participants of a needle exchange program. Between June 1998 and May 1999, needle exchange program participants requesting tuberculosis screening underwent interviews regarding demographics and risk factors for tuberculosis and HIV infection. The first 190 participants underwent traditional interviewer-assisted questionnaires, whereas the remaining 92 underwent computer-assisted questionnaires. Data were analyzed by interview technique using odds ratios (OR) and multiple logistic regression. Among 282 participants, demographic characteristics, health status, HIV serostatus, visits to homeless shelters, alcohol intake, and cigarette smoking were all similar by interview technique. However, respondents receiving computer-assisted questionnaires were more likely than those receiving interviewer-assisted questionnaires to report smoking marijuana (OR = 5.56), crack (OR = 1.88), and heroin (OR = 2.60); as well as sharing cocaine smoking equipment (OR = 4.49), sharing heroin smoking equipment (OR = 2.85), "shotgunning" (OR = 4.48), and visiting crack houses (OR = 4.39). In the final multivariate model, respondents receiving computer-assisted questionnaires were more likely to report "shotgunning" and visiting a crack house relative to respondents receiving interviewer-assisted questionnaires. In conclusion, increased odds of high-risk behaviors for tuberculosis and HIV infection among computer-assisted questionnaire respondents support the use of computer-assisted questionnaires to ascertain risk behavior data for both tuberculosis and HIV. KEYWORDS: tuberculosis; HIV; self-report; drug use; computer-assisted
Baltimore↗
Sex differences in risk factors for hiv seroconversion among injection drug users: a 10-year perspective.
BACKGROUND: Injection drug use directly or indirectly accounts for nearly half the annual human immunodeficiency virus (HIV) infections in the United States. Prospective studies that investigate both sexual and parenteral HIV risks among injection drug users (IDUs) are needed. We studied factors for HIV seroconversion among male and female IDUs in Baltimore, Md. METHODS: The HIV-negative IDUs (1447 male and 427 female) were recruited into a prospective study from 1988 to 1989 or in 1994. Participants underwent semiannual HIV tests and surveys through December 1998. Poisson regression was used to identify risk factors for HIV seroconversion, stratified by sex. Behaviors were treated as time-dependent covariates that varied at each semiannual period. RESULTS: Subjects were primarily African American (91%), and median age at enrollment was 35 years. Incidence of HIV was 3.14 per 100 person years (95% confidence interval, 2.78-3.53) and did not significantly differ by sex. Younger age independently predicted HIV seroconversion for both men and women. Among men, factors that independently predicted HIV seroconversion were the following: less than a high school education, recent needle sharing with multiple partners, daily injection, and shooting-gallery attendance. The incidence of HIV was double for men recently engaging in homosexual activity and cocaine injection. Among women, the incidence of HIV was more than double for those recently reporting sexually transmitted diseases. CONCLUSIONS: The incidence of HIV remained high among IDUs in Baltimore over the past decade. Risk factors for HIV seroconversion differed markedly by sex. Predominant risks among men included needle sharing and homosexual activity; among women, factors consistent with high-risk heterosexual activity were more significant than drug-related risks. Human immunodeficiency virus interventions aimed at IDUs should be sex-specific and incorporate sexual risks.
Adolescent↗
Factors associated with the response to antiretroviral therapy among HIV-infected patients with and without a history of injection drug use.
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Antiretroviral Therapy, Highly Active↗
Determinants of heterogeneous adherence to HIV-antiretroviral therapies in the Multicenter AIDS Cohort Study.
Assessment of adherence to HIV antiretroviral therapy (ART) is required for studying therapeutic effectiveness and identifying subgroups needing focused education. The study's goals were to describe the level of ART adherence using self-reported recall over a 4-day period and to characterize determinants of lower adherence. The interaction between adherence and drug holidays on level of HIV RNA also was investigated. Perfect self-reported adherence was defined as taking all doses and numbers of pills as prescribed for current HIV medications. Independent predictors of <100% adherence were determined using multivariate logistic regression. Among 539 men, 419 (77.7%) were 100% adherent by the algorithm using self-reported data. HIV-1 RNA was <50 copies/ml in 48.2% of the adherent group versus 33.7% in the less adherent group (p = .015). This proportion dropped to 28% if a drug holiday was reported in addition to lower adherence. A drug holiday was not virologically detrimental if the participant was otherwise adherent. Determinants of lower adherence included African American race (odds ratio [OR], 2.4; p = .008), income <U.S.$50,000 (OR, 2.2; p = .002), no outpatient visits (OR, 3.6; p = .003) and increasing numbers of ART medications (OR, 4.5; p = .001). These data support the validity of using a questionnaire to assess adherence in observational studies. Identification of individuals with characteristics associated with lower adherence provides the basis for interventions to enhance adherence and optimize effective therapies.
Adult↗
Therapy naivete in the era of potent antiretroviral therapy.
Antiretroviral therapy (ART) use was examined in a cohort of homosexual men infected with HIV-1 for long periods. Multivariate logistic regression models, stratified by clinical indication (below and above 500 CD4 cells/microl or prior AIDS), were used to determine predictors of ART naivete. Of the 673 men seen at visit 28 (10/97-4/98), 89 (13.2%) never used ART and 548 (81.4%) were current users; 55% of the therapy-naive were ART eligible. Lower CD4 cell counts predicted (P <.001) ART use. Determinants of therapy naivete differed by clinical indication. African-American race and no prior ambulatory visit predicted (P <.05) ART naivete in men with > or =500 CD4 cells/microl. Among those with clinical indications, less education, younger age, multiple sexual partners, and no prior ambulatory visit significantly predicted ART naivete. In this era of effective ART, use was not universal. Besides disease markers, these nonclinical determinants need to be considered for promoting population therapy effectiveness.
Adult↗
Prevalence of type 2 diabetes mellitus among persons with hepatitis C virus infection in the United States.
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Diabetes Mellitus, Type 2↗
Factors associated with adolescent initiation of injection drug use.
OBJECTIVE: The purpose of this study was to evaluate the extent to which demographic, sexual, and non-injection drug use practices predict adolescent initiation of injection drug use. METHODS: Street recruited injection drug users 15-30 years of age in Baltimore, Maryland, who initiated injection within five years of study enrollment, completed a questionnaire that included a year-by-year history regarding the five years prior to initiation of injection. Factors associated with initiation during adolescence (< or = 21 years of age) versus young adulthood (>21 ) were determined using logistic regression. RESULTS: Of 226 participants, most were female (61%) and African American (64%). Median age of participants was 25; median age at initiation of injection was 23. Factors significantly associated with adolescent initiation in multivariate analysis included race other than African American, and practices prior to initiating injection including condom use, lack of cocaine use, exclusive crack smoking just prior to initiation, and smoking marijuana. Adolescent initiates also had shorter durations of illicit drug use prior to initiating injection. CONCLUSION: Short-term non-injection drug use, particularly exclusive crack smoking, was associated with adolescent initiation of injection drug use. Early prevention efforts targeting this high-risk group of younger drug users are warranted in order to delay or prevent onset of injection drug use.
Adolescent↗
Human immunodeficiency virus seroconversion and evolution of the hepatitis C virus quasispecies.
When chronic hepatitis C virus (HCV) infections are complicated by acquisition of human immunodeficiency virus (HIV), liver disease appears to accelerate and serum levels of HCV RNA may rise. We hypothesized that HIV might affect the HCV quasispecies by decreasing both complexity (if HIV-induced immunosuppression lessens pressure for selecting HCV substitutions) and the ratio of nonsynonymous (d(N)) to synonymous (d(S)) substitutions, because d(N) may be lower (if there is less selective pressure). To test this hypothesis, we studied the evolution of HCV sequences in 10 persons with chronic HCV infection who seroconverted to HIV and, over the next 3 years, had slow or rapid progression of HIV-associated disease. From each subject, four serum specimens were selected with reference to HIV seroconversion: (i) more than 2 years prior, (ii) less than 2 years prior, (iii) less than 2 years after, and (iv) more than 2 years after. The HCV quasispecies in these specimens was characterized by generating clones containing 1 kb of cDNA that spanned the E1 gene and the E2 hypervariable region 1 (HVR1), followed by analysis of clonal frequencies (via electrophoretic migration) and nucleotide sequences. We examined 1,320 cDNA clones (33 per time point) and 287 sequences (median of 7 per time point). We observed a trend toward lower d(N)/d(S) after HIV seroconversion in 7 of 10 subjects and lower d(N)/d(S) in those with rapid HIV disease progression. However, the magnitude of these differences was small. These results are consistent with the hypothesis that HIV infection alters the HCV quasispecies, but the number of subjects and observation time may be too low to characterize the full effect.
Adult↗
[The difference between men and women drug users in seroconversion risk factors].
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Female↗
Prevalence of type 2 diabetes mellitus among persons with hepatitis C virus infection in the United States.
BACKGROUND: Hepatitis C virus (HCV) infection may contribute to the development of diabetes mellitus. This relationship has not been investigated at the population level, and its biological mechanism remains unknown. OBJECTIVE: To examine the prevalence of type 2 diabetes among persons with HCV infection in a representative sample of the general adult population of the United States. DESIGN: Cross-sectional national survey. SETTING: The Third National Health and Nutrition Examination Survey, 1988-1994. PARTICIPANTS: 9841 persons older than 20 years of age for whom data on HCV infection and diabetes were complete. MEASUREMENTS: The presence of diabetes was ascertained by using American Diabetes Association guidelines based on fasting plasma glucose measurement and medication history. Presence of HCV infection was assessed by testing for serum HCV-specific antibodies (anti-HCV). RESULTS: Of the 9841 persons evaluated, 8.4% had type 2 diabetes and 2.1% were anti-HCV positive. Type 2 diabetes occurred more often in persons who were older, were nonwhite, had a high body mass index, and had low socioeconomic status. Type 2 diabetes was less common in persons who acknowledged previous illicit drug use. After adjustment for these factors, persons 40 years of age or older with HCV infection were more than three times more likely than those without HCV infection to have type 2 diabetes (adjusted odds ratio, 3.77 [95% CI, 1.80 to 7.87]). None of the 19 persons with type 1 diabetes were anti-HCV positive. CONCLUSION: In the United States, type 2 diabetes occurs more often in persons with HCV infection who are older than 40 years of age.
Adult↗
Correlates of enrollment in methadone maintenance treatment programs differ by HIV-serostatus.
OBJECTIVES: To identify correlates of enrollment in methadone maintenance treatment programs (MMTP) among a prospective cohort of injection drug users (IDUs) in Baltimore, Maryland. METHODS: A total of 1480 IDUs undergoing semi-annual HIV tests and interviews were studied between 1994 and 1998, during which time a needle exchange program was introduced. Longitudinal analysis using generalized estimating equations was used to identify correlates of MMTP participation over time. RESULTS: Although similar proportions of HIV-seropositive and -seronegative IDUs enrolled in MMTP during follow-up (26 versus 22%, respectively), correlates of enrollment differed by HIV-serostatus. Among HIV-seropositive participants, older age [adjusted odds ratio (AOR, 1.37)] was associated with enrollment in MMTP. Among HIV-seronegative IDUs, factors associated with not enrolling in MMTP were being African American (AOR, 0.22) and having been recently incarcerated (AOR, 0.62) or homeless (AOR, 0.72). In both groups, females were twice as likely to be enrolled in MMTP, and those with Medicaid were 1.5 times more likely to be enrolled. When behavioral factors were lagged one visit, needle exchange program attendance was positively associated with MMTP enrollment among HIV-negative IDUs (AOR, 2.10); however, this association diminished significantly over time as dedicated treatment slots for needle exchange program participants became saturated. CONCLUSIONS: These findings underscore the need to improve access to MMTP, especially to certain subgroups such as African-Americans, the homeless, incarcerated and uninsured. Our data suggest that health care providers and needle exchange programs can facilitate enrollment into MMTP provided that adequate treatment slots are consistently available to this particularly vulnerable population.
Adult↗