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Biomedical subjects

Steffanie A Strathdee

Publications and source records attributed to Steffanie A Strathdee.

At least 19 recordsLinked to original sources
PubMed2025

VANTAGE: van-based real-time HIV sequencing for transmission mapping and drug resistance profiling in war-affected Ukraine.

We deployed the VANTAGE (VAN for Transmissible Agent Genomic Epidemiology) mobile system in Lviv, Ukraine, demonstrating end-to-end sequencing of dried blood spot samples within a clinic van usually serving de-occupied and frontline regions. HIV-1 pol sequences were obtained from 50% of samples, all subtype A6. Median time to 100× coverage was 38 min. Phylogenetic analysis revealed a local transmission cluster including a displaced person and the non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutation E138A, supporting real-time HIV genomic surveillance in humanitarian crises.

Humans↗
PubMed2007

Factors associated with premature mortality among young injection drug users in Vancouver.

BACKGROUND: Young injection drug users (IDUs) may be at increased risk of premature mortality due to the health risks associated with injection drug use including overdoses and infections. However, there has been little research conducted on mortality causes, rates and associations among this population. We undertook this study to investigate patterns of premature mortality, prior to age 30 years, among young IDUs. METHODS: Since 1996, 572 young (< or = 29 years) IDUs have been enrolled in the Vancouver Injection Drug Users Study (VIDUS). Semi-annually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and hepatitis C (HCV). Mortality data have been continually updated through linkages with the Provincial Coroner's Office. Crude and age-specific mortality rates, standardized mortality ratios, and life expectancy measures were calculated using person-time methods. Predictors of mortality were identified using Cox regression analyses. FINDINGS: Twenty-two participants died prior to age 30 years during the follow-up period for an overall crude mortality rate of 1,368 per 100,000 person-years. Overall, young IDUs were 16.4 times (95% confidence interval [CI]; 9.1-27.1) more likely to die; young women IDUs were 54.1 times (95%CI; 29.6-90.8) and young men IDUs were 12.9 times (95%CI; 5.5, 25.3) more likely to die when compared to the Canadian non-IDU population of the same age. The leading observed cause of death among females was: homicide (N = 9); and among males: suicide (N = 3) and overdose (N = 3). In Cox regression analyses, factors associated with mortality were, HIV infection (Hazard Ratio [HR]: 4.55; CI: 1.92-10.80) and sex work (HR: 2.76; CI: 1.16-6.56). INTERPRETATION: Premature mortality was 13 and 54 times higher among young men and women who use injection drugs in Vancouver than among the general population in Canada. The majority of deaths among the women were attributable to homicide, suggesting that interventions should occur not only through harm reduction services but also through structural interventions at the legal and policy level.

Journal Article↗
PubMed2007

Rates of inappropriate antiretroviral prescription among injection drug users.

BACKGROUND: Although the survival benefits of antiretroviral therapy (ART) for the treatment of HIV infection are well established, the clinical management of HIV disease continues to present major challenges. There are particular concerns regarding access to appropriate HIV treatment among HIV-infected injection drug users (IDU). METHODS: In a prospective cohort study of HIV-infected IDU in Vancouver, Canada, we examined initial ART regimens vis-à-vis the provincial government's therapeutic guidelines at the time ART was initiated. Briefly, there have been four sets of guidelines: Era 1 (1992 to November 1995; double-drug (dual NRTIs) ART for patients with a CD4 cell count of 350 or less); Era 2 (December 1995 to May 1996; double-drug therapy for patients with a CD4+ cell count of 500 or less); Era 3 (June 1996 to June 1997; triple-drug therapy (dual NRTIs with a PI or NNRTI) for patients who had a plasma viral load of > 100,000 HIV-1 RNA copies/mL; dual therapy with two NRTIs for those with a plasma viral load of 5,000 to 100,000 HIV-1 RNA copies/mL); Era 4 (since July 1997; universal use of triple drug therapy as first-line treatment). RESULTS: Between May 1996 and May 2003, 431 HIV-infected individuals were enrolled into the cohort. By May 31, 2003, 291 (67.5%) individuals had initiated ART. We noted instances of inappropriate antiretroviral prescription in each guideline era, with 9 (53%) in Era 1, 3 (12%) in Era 2, 22 (28%) in Era 3, and 23 (15%) in Era 4. Of the 57 subjects who received an inappropriate ART regimen initially, 14 never received the appropriate therapy; among the remaining 43, the median time to the initiation of a guideline-appropriate ART regimen was 12 months (inter-quartile range 5-20). CONCLUSION: The present study identified measurable rates of guideline-inappropriate ART prescription for patients who were injection drug users. Rates were highest in the era of dual therapy, although high rates persisted into the triple-therapy era. As therapeutic guidelines continue to evolve, it is critical that mechanisms be put in place to ensure prescription of ART combinations for IDU that are consistent with current expert recommendations.

Journal Article↗
PubMed2007

A qualitative exploration of gender in the context of injection drug use in two US-Mexico border cities.

Injection drug use is of increasing concern along the U.S.-Mexico border where Tijuana and Ciudad (Cd.) Juarez are located. We conducted a qualitative study to explore the context of drug use, with a focus on gender differences. In-depth interviews were conducted with 10 male and 10 female injection drug users (IDUs) in Tijuana and 15 male and 8 female IDUs in Cd. Juarez. Topics included types of drugs used, injection settings, access to sterile needles and environmental influences. Interviews were taped, transcribed and translated. Content analysis was conducted to identify themes. Several themes emerged with respect to gender: (a) how drugs were obtained; (b) where drugs were used; (c) relationship dynamics surrounding drug use; and (d) sex in exchange for money or drugs. Men reported buying and injecting in shooting galleries and other locations, whereas women tended to buy and inject drugs with people they knew and trusted. All men reported having shared syringes in shooting galleries, often with strangers. In these two cities, venue-based interventions may be more appropriate for male IDUs, whereas personal network interventions may be more appropriate among female IDUs.

Adult↗
PubMed2007

Design and feasibility of a randomized behavioral intervention to reduce distributive injection risk and improve health-care access among hepatitis C virus positive injection drug users: the Study to Reduce Intravenous Exposures (STRIVE).

Hepatitis C virus (HCV) is hyperendemic among injection drug users (IDUs). However, few scientifically proven interventions to prevent secondary transmission of HCV from infected IDUs to others exist. This report describes the design, feasibility, and baseline characteristics of participants enrolled in the Study to Reduce Intravenous Exposure (STRIVE). STRIVE was a multisite, randomized-control trial to test a behavioral intervention developed to reduce distribution of used injection equipment (needles, cookers, cottons, and rinse water) and increase health-care utilization among antibody HCV (anti-HCV) positive IDUs. STRIVE enrolled anti-HCV positive IDU in Baltimore, New York City, and Seattle; participants completed behavioral assessments and venipuncture for HIV, HCV-RNA, and liver function tests (LFTs) and were randomized to attend either a six-session, small-group, peer-mentoring intervention workshop or a time-matched, attention-control condition. Follow-up visits were conducted at 3 and 6 months. At baseline, of the 630 HCV-positive IDUs enrolled (mean age of 26 years, 60% white, 76% male), 55% reported distributive needle sharing, whereas 74, 69, and 69% reported sharing cookers, cottons, and rinse water, respectively. Health-care access was low, with 41% reporting an emergency room as their main source of medical care. Among those enrolled, 66% (418/630) were randomized: 53% (222/418) and 47% (196/418) to the intervention and control conditions, respectively. Follow-up rates were 70 and 73% for the 3- and 6-month visits, respectively. As distributive sharing of used injection equipment was common while reports of receiving HCV care were low, these findings indicate an urgent need for HCV-related interventions with IDUs and demonstrate the acceptability and feasibility to do so.

Adolescent↗
PubMed2007

Unprotected anal intercourse and substance use before and after HIV diagnosis among recently HIV-infected men who have sex with men.

OBJECTIVE: The objective of this study was to assess associations between unprotected anal intercourse (UAI) and substance use before and after HIV diagnosis among recently HIV-infected MSM. STUDY DESIGN: Two hundred seven MSM completed computer-assisted self-interviews regarding type and timing of sexual activity and substance use with their last 3 partners. Date of HIV diagnosis was extracted from medical records. Generalized estimating equations, including interaction terms, were used to assess associations between substance use and UAI before and after HIV diagnosis. RESULTS: Among partners with whom sexual activity occurred before diagnosis, UAI was associated with methamphetamine use alone (odds ratio = 7.12) and a combination of methamphetamine and other substances (odds ratio = 4.06). However, after HIV diagnosis, UAI was associated with use of substances other than methamphetamine (odds ratio = 3.36), but not methamphetamine alone. CONCLUSIONS: Use of illicit substances may be differentially associated with UAI based on knowledge of HIV status and could have implications for prevention of HIV transmission.

Adolescent↗
PubMed2006

Efficacy of a behavioral intervention for increasing safer sex behaviors in HIV-positive MSM methamphetamine users: results from the EDGE study.

BACKGROUND: Methamphetamine use has been associated with rising STI/HIV transmission rates, particularly among men who have sex with men (MSM). Interventions which successfully reduce risk for HIV transmission among this population are a public health priority. This study examined the efficacy of a behavioral intervention for increasing safer sex behaviors in the context of ongoing methamphetamine use in a sample of HIV-positive, methamphetamine-using MSM. METHODS: Three-hundred and forty-one participants from San Diego, CA were randomly assigned to receive either a safer sex behavioral intervention (EDGE) or a time-equivalent diet-and-exercise attention-control condition. Random effects regression analyses were used to evaluate change in safer sex behaviors over a 12-month period. RESULTS: Participants in the EDGE intervention engaged in significantly more protected sex acts at the 8-month (p=0.034) and 12-month assessment (p=0.007). By 12-months post-baseline, a greater percentage of protected sex acts was observed for EDGE (25.8%) vs. control participants (18.7%) (p=0.038). There was a significant time-by-intervention interaction (p=0.018) for self-efficacy for condom use, suggesting that EDGE participants' self-efficacy demonstrated a greater increase over time compared to control participants. CONCLUSIONS: These results suggest that it is possible to reduce high risk sexual behaviors in the context of ongoing methamphetamine use among HIV-infected MSM.

Adult↗
PubMed2006

Vulnerability to HIV infection among sex worker and non-sex worker female injecting drug users in Dhaka, Bangladesh: evidence from the baseline survey of a cohort study.

BACKGROUND: Very little is known about female injecting drug users (IDU) in Bangladesh but anecdotal evidence suggests that they are hidden and very vulnerable to HIV through both their injection sharing and sexual risk behaviors. In order to better understand the risks and vulnerability to HIV of female IDU, a cohort study was initiated through which HIV prevalence and risk behaviors was determined. METHODS: All female IDU (those who had injected in the last six months and were 15 years or older) who could be identified from three cities in the Dhaka region were enrolled at the baseline of a cohort study. The study was designed to determine risk behaviors through interviews using a semi-structured questionnaire and measure prevalence of HIV, hepatitis C and syphilis semiannually. At the baseline of the cohort study 130 female IDU were recruited and female IDU selling sex in the last year (sex workers) versus those not selling sex (non-sex workers) were compared using descriptive statistics and logistic regression. RESULTS: Of the 130 female IDU enrolled 82 were sex workers and 48 were non-sex workers. None had HIV but more sex workers (60%) had lifetime syphilis than non-sex workers (37%). Fewer sex worker than non-sex worker IDU lived with families (54.9% and 81.3% respectively), but more reported lending needles/syringes (29.3% and 14.6% respectively) and sharing other injection paraphernalia (74.4% and 56.3% respectively) in the past six months. Although more sex workers used condoms during last sex than non-sex workers (74.4% and 43.3% respectively), more reported anal sex (15.9% and 2.1% respectively) and serial sex with multiple partners (70.7% and 0% respectively). Lifetime sexual violence and being jailed in the last year was more common in sex workers. CONCLUSION: Female IDU are vulnerable to HIV through their injection and sexual risk behaviors and sex worker IDU appear especially vulnerable. Services such as needle exchange programs should become more comprehensive to address the needs of female IDU.

Journal Article↗
PubMed2006

Multiperson use of syringes among injection drug users in a needle exchange program: a gene-based molecular epidemiologic analysis.

Syringe-sharing behaviors among injection drug users (IDUs) are typically based on self-reports and subject to socially desirable responding. We used 3 short tandem repeat (STR) genetic biomarkers to detect sharing in 2,512 syringes exchanged by 315 IDUs in the Baltimore needle exchange program (NEP; 738 person-visits). Demographic characteristics as well as direct and indirect needle-sharing behaviors corresponding to the closest AIDS Link to Intravenous Experience (ALIVE) study visits were examined for association with multiperson use (MPU) of syringes. Overall, 56% of the syringes exchanged at the Baltimore NEP had evidence of MPU. Less MPU of syringes (48% vs. 71%; P < 0.0001) was seen with more rapid syringe turnaround (<3 days). IDUs always exchanging their own syringes ("primary" syringes) were less likely to return syringes with evidence of MPU (52%) than those who exchanged syringes for others ("secondary" syringes; 64%; P = 0.0001) and those exchanging primary and secondary syringes (58%; P = 0.004). In a multivariate analysis restricted to primary exchangers, MPU of syringes was associated with sharing cotton (adjusted odds ratio [AOR] = 2.06, 95% confidence interval [CI]: 1.30 to 3.28), lending syringes (AOR = 1.70, 95% CI: 1.24 to 2.34), and injecting less than daily (AOR = 0.64, 95% CI: 0.43 to 0.95). These findings support additional public health interventions such as expanded syringe access to prevent HIV and other blood-borne infections. Testing of STRs represents a promising approach to examining and accessing complex behavioral data, including syringe sharing.

Adult↗
PubMed2006

Unprotected anal intercourse and substance use among men who have sex with men with recent HIV infection.

OBJECTIVES: To examine within-subjects and combined between- and within-subjects associations between substance use and unprotected anal intercourse (UAI) among men who have sex with men (MSM) with recent HIV infection. METHODS: One hundred ninety-four MSM who were recently infected with HIV completed a computer-assisted questionnaire regarding sexual behaviors and substance use with their last 3 partners. Associations between UAI and substance use were assessed using conditional logistic regression (CLR) to assess associations among the 116 MSM reporting UAI with some but not all partners and generalized linear mixed effects models (GLMMs) to examine a combination of within- and between-subjects associations in the entire sample (N = 194). RESULTS: In multivariate CLR models and GLMMs, UAI was associated with the use of methamphetamine (odds ratio [OR] = 4.9 and OR = 3.5, respectively), marijuana (OR = 4.0 and OR = 2.2, respectively) and erectile dysfunction medications (EDMs) when used with a main partner (OR = 13.8 and OR = 10.1, respectively). CONCLUSIONS: Results indicate that a direct association may exist between specific substances and UAI and provide evidence that the use of methamphetamine and EDMs may contribute to HIV transmission.

Adult↗
PubMed2006

HIV incidence among injection drug users in Baltimore, Maryland (1988-2004).

BACKGROUND: We examined recent trends (1999-2004) in HIV incidence among a cohort of injection drug users (IDUs) followed since 1988 in Baltimore, Maryland. METHODS: One thousand eighty-three HIV-seronegative individuals with a history of injection drug use were recruited between 1988 and 1998 and returned for >or=1 semiannual follow-up visit, where they underwent HIV antibody testing and interviews eliciting risk behaviors. Person-time methods were used to calculate HIV incidence rates per 100 person-years (PYs). RESULTS: Over 14,770 PYs, 304 individuals seroconverted to HIV (2.06 per 100 PYs). Annual incidence declined from 4.57 in 1988 to 0.53 per 100 PYs in 2004. Similarly, among individuals actively injecting drugs, incidence steadily declined from 5.43 in 1988 to 0 in 2004, with the exception of 2003, when an incidence of 2.59 per 100 PYs was observed. Reported sexual risk behaviors and drug injection declined from 1988 through 2004, but among those actively injecting, reported needle sharing declined from 1988 through 1998 and then increased from 30% in 1998 to nearly 40% in 2003 through 2004. CONCLUSIONS: Long-term declines in HIV incidence among IDUs are consistent with other reports; however, in 2003, we observed an unexpected increase in seroconversion that seems to be related to needle sharing. Although additional follow-up is needed to identify trends, these data indicate the need to reinforce HIV prevention efforts and to continue surveillance of drug users' behaviors.

Adult↗
PubMed2006

High HCV seroprevalence and HIV drug use risk behaviors among injection drug users in Pakistan.

INTRODUCTION: HIV and HCV risk behaviors among injection drug users (IDUs) in two urban areas in Pakistan were identified. METHODS: From May to June 2003, 351 IDUs recruited in harm-reduction drop-in centers operated by a national non-governmental organization in Lahore (Punjab province) and Quetta (Balochistan province) completed an interviewer-administered survey and were tested for HIV and HCV. Multivariable logistic regression identified correlates of seropositivity, stratifying by site. All study participants provided written, informed consent. RESULTS: All but two were male; median age was 35 and <50% had any formal education. None were HIV-positive; HCV seroprevalence was 88%. HIV awareness was relatively high, but HCV awareness was low (19%). Injection behaviors and percutaneous exposures such as drawing blood into a syringe while injecting ('jerking'), longer duration of injection, and receiving a street barber shave were significantly associated with HCV seropositivity. DISCUSSION: Despite no HIV cases, overall HCV prevalence was very high, signaling the potential for a future HIV epidemic among IDUs across Pakistan. Programs to increase needle exchange, drug treatment and HIV and HCV awareness should be implemented immediately.

Journal Article↗
PubMed2006

Elevated rates of HIV infection among young Aboriginal injection drug users in a Canadian setting.

OBJECTIVES: Recent reports have suggested that Aboriginal and American Indian people are at elevated risk of HIV infection. We undertook the present study to compare socio-demographic and risk variables between Aboriginal and non-Aboriginal young (aged 13 - 24 years) injection drug users (IDUs) and characterize the burden of HIV infection among young Aboriginal IDUs. METHODS: We compared socio-demographic and risk variables between Aboriginal and non-Aboriginal young IDUs. Data were collected through the Vancouver Injection Drug Users Study (VIDUS). Semi-annually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and Hepatitis C (HCV). RESULTS: To date over 1500 Vancouver IDU have been enrolled and followed, among whom 291 were aged 24 years and younger. Of the 291 young injectors, 80 (27%) were Aboriginal. In comparison to non-Aboriginal youth, Aboriginal youth were more likely to test seropositive for either HIV (20% vs 7%, p=< 0.001) or Hepatitis C virus (HCV) (66% vs 38%, p =< 0.001), be involved in sex work and live in the city's IDU epi-centre at baseline. After 48 months of follow-up, Aboriginal youth experienced significantly higher HIV seroconversion rates than non-Aboriginal youth, 27.8 per ppy (95% CI: 13.4-42.2) vs. 7.0 per ppy (95% CI: 2.3-11.8) respectively (log-rank p = 0.005) and the incidence density over the entire follow-up period was 12.6 per 100 pyrs (CI: 6.49-21.96) and 3.9 per 100 pyrs (CI: 1.8-7.3) respectively. INTERPRETATION: These findings demonstrate that culturally relevant, evidence based prevention programs are urgently required to prevent HIV infection among Aboriginal youth.

Journal Article↗
PubMed2006

Eligibility for treatment of hepatitis C virus infection among young injection drug users in 3 US cities.

Among 404 injection drug users aged 18-35 who tested positive for hepatitis C virus (HCV) RNA, 96% had conditions that are potentially unwarranted contraindications for HCV treatment (e.g., problem drinking, moderate-to-severe depression, and recent drug injection). Restrictive eligibility criteria may deny treatment to a large proportion of patients who could benefit from it.

Adolescent↗
PubMed2006

Unknown biological mixtures evaluation using STR analytical quantification.

Allelic quantification of STRs, where the presence of three or more alleles represents mixtures, provides a novel method to identify mixtures from unknown biological sources. The allelic stutters resulting in slightly different repeat containing products during fragment amplification can be mistaken for true alleles complicating a simple approach to mixture analysis. An algorithm based on the array of estimated stutters from known samples was developed and tuned to maximize the identification of true non-mixtures through the analysis of three pentanucleotide STRs. Laboratory simulated scenarios of needle sharing generated 58 mixture and 38 non-mixture samples that were blinded for determining the number of alleles. Through developing and applying an algorithm that additively estimates stuttering around the two highest peaks, mixtures and non-mixtures were characterized with sensitivity of 77.5, 82.7 and 58% while maintaining the high specificity of 100, 97.4 and 100 for the W, X, and Z STRs individually. When all three STRs were used collectively, the resulting sensitivity and specificity was 91.4 and 97.4%, respectively. The newly validated approach of using multiple STRs as highly informative biomarkers in unknown sample mixture analyses has potential applications in genetics, forensic science, and epidemiological studies.

Algorithms↗
PubMed2006

Behavioral interventions for HIV-positive and HCV-positive drug users.

The nature, context and frequency of use of various licit and illicit non-injection drugs associated with an elevated risk of HIV infection. Beyond HIV, a high proportion of HIV-infected IDUs are co-infected with HCV (hepatitis C virus). In this review, we provide a brief review of the epidemiology of these problems, discuss behavioral interventions that can reduce ongoing high risk behaviors among HIV-seropositive IDUs and MSM-DUs, and review the literature which has evaluated their effectiveness. The majority of these interventions have focused on HIV-seronegative heterosexuals and therefore need to be considered in this larger context; however, where possible we discuss the potential impact of these interventions among HIV-seropositive persons. In addition, we briefly discuss interventions which have the potential to simultaneously reduce ongoing transmission of both HIV and HCV. Finally, given the dearth of information on the effectiveness of behavioral interventions in reducing the burden of the HIV and HCV epidemics among persons already infected with either or both viruses, we describe some newer, promising interventions and offer suggestions for future studies.

Anti-Retroviral Agents↗
PubMed2006

Predictors of early initiation of vaginal and oral sex among urban young adults in Baltimore, Maryland.

Over the past three decades, most research on adolescent sexual behavior has focused on vaginal intercourse and related behaviors, including contraception and unintended pregnancy. In this study, we describe the prevalence and correlates of vaginal, oral, and anal sex in an epidemiologically defined population in Baltimore, Maryland. Young adults (ages 18-24), who had been enrolled in a behavioral intervention trial during elementary school, were interviewed by telephone between 1998 and 2002 to assess their sexual behavior. Of 1679 respondents interviewed, 70.8% were Black and 55% were women. Overall, 93% of the young adults reported vaginal intercourse, 78% reported receiving oral sex, 57% reported performing oral sex, and 10% reported receptive anal intercourse. Among men, 27% reported insertive anal intercourse. Blacks initiated vaginal intercourse at an earlier age than Whites; White women performed oral sex earlier than Black women. Significant interactions were observed between age of first vaginal partner and both gender and race/ethnicity. Blacks with older partners initiated sex at an earlier age than both Blacks with a partner the same age or younger and Whites. We also observed a relationship between older female sex partners and earlier vaginal sex initiation among men. We conclude that older sex partners play an important role in sexual initiation among young adults. In light of the rates of oral and anal sex, sexual education and intervention programs should address the risk for unintended consequences of these behaviors.

Adult↗