A Decline in HIV Testing Among Persons Who Inject Drugs in the Seattle Area, 2004-2015.

BACKGROUND: Promoting HIV testing is a key component of the public health response to HIV. Assessing HIV testing frequency among persons who inject drugs (PWID) monitors the status of these efforts and can identify unmet needs and opportunities to more effectively promote testing. METHODS: Data were combined from 4 Seattle-area surveys of PWID from the National HIV Behavioral Surveillance (NHBS) program (2005-2015) and 6 surveys of Needle Exchange clients (2004-2015). RESULTS: The proportion of PWID reporting an HIV test in the previous 12 months declined from 64% in 2005% to 47% in 2015 in the NHBS surveys and from 72% to 58% in the Needle Exchange surveys. These declines persisted in multivariate analyses controlling for differences in the study populations in age, race, sex, area of residence, education, current homelessness, drug most frequently injected, daily injection frequency, and combined male-to-male sex and amphetamine injection status. The proportion of NHBS participants reporting not knowing the HIV status of their last injection partner increased from 38% to 45%. The proportion not knowing the HIV status of their last sex partner increased from 27% to 38%. CONCLUSIONS: A decrease in HIV testing was found in 2 independent Seattle-area study populations. This was complemented by increases in the proportions not knowing the HIV status of their last sex and last injection partners. Research is needed to ascertain if such declines are observed elsewhere, the reasons for the decline, and appropriate means to effectively attain optimal HIV testing frequency among PWID.

Reduction in Needle Sharing Among Seattle-Area Injection Drug Users Across 4 Surveys, 1994-2013.

OBJECTIVES: We evaluated time trends in sharing needles and other injection equipment from 1994 to 2013 among injection drug users in the Seattle, Washington area. METHODS: We combined data from 4 sources: the Risk Activity Variables, Epidemiology, and Network (RAVEN) study, recruited from institutional settings; the Kiwi study, recruited from jails; National HIV Behavioral Surveillance system (NHBS) surveys, which used respondent-driven sampling; and surveys at needle-exchange sites. RESULTS: Levels of needle sharing were higher in the earlier studies: RAVEN, 1994 to 1997 (43%) and Kiwi, 1998 to 2002 (61%). In the NHBS surveys, the initial level of 44% in 2005 declined to 31% in the period 2009 to 2012. Across needle-exchange surveys (2009-2013) the level was 21%. There was a parallel reduction in sharing other injection equipment. These trends persisted after control for sociodemographic and risk-associated variables. There was a contemporaneous increase in the number of needles distributed by local needle exchanges and a decline in the number of reported HIV cases among injection drug users. CONCLUSIONS: The apparent long-term reduction in sharing injection equipment suggests substantial success in public health efforts to reduce the sharing of injection equipment.

Unmet health care needs and hepatitis C infection among persons who inject drugs in Denver and Seattle, 2009.

Persons who inject drugs (PWID) shoulder the greater part of the hepatitis C virus (HCV) epidemic in the USA. PWID are also disproportionately affected by limited access to health care and preventative services. We sought to compare current health care coverage, HCV, and HIV testing history, hepatitis A and B vaccination coverage, and co-occurring substance use among PWID in two US cities with similar estimated numbers of PWID. Using data from the 2009 National HIV Behavioral Surveillance system in Denver (n = 428) and Seattle (n = 507), we compared HCV seroprevalence and health care needs among PWID. Overall, 73 % of participants who tested for HCV antibody were positive. Among those who were HCV antibody-positive, vaccination coverage for hepatitis A and B was low (43 % in Denver and 34 % in Seattle) and did not differ significantly from those who were antibody-negative. Similarly, participation in alcohol or drug treatment programs during the preceding 12 months was not significantly higher among those who were HCV antibody-positive in either city. Significantly fewer participants in Denver had health care coverage compared to Seattle participants (45 vs. 67 %, p < 0.001). However, more participants in Seattle reported being disabled for work and, thus, more likely to be receiving health care coverage through the federal Medicaid program. In both cities, the vast majority of those who were aware of their HCV infection reported not receiving treatment (90 % in Denver and 86 % in Seattle). Our findings underscore the need to expand health care coverage and preventative medical services for PWID. Furthermore, our findings point to the need to develop comprehensive and coordinated care programs for infected individuals.

Assessing differences in groups randomized by recruitment chain in a respondent-driven sample of Seattle-area injection drug users.

PURPOSE: Respondent-driven sampling (RDS) is a form of peer-based study recruitment and analysis that incorporates features designed to limit and adjust for biases in traditional snowball sampling. It is being widely used in studies of hidden populations. We report an empirical evaluation of RDS's consistency and variability, comparing groups recruited contemporaneously, by identical methods and using identical survey instruments. METHODS: We randomized recruitment chains from the RDS-based 2012 National HIV Behavioral Surveillance survey of injection drug users in the Seattle area into two groups and compared them in terms of sociodemographic characteristics, drug-associated risk behaviors, sexual risk behaviors, human immunodeficiency virus (HIV) status and HIV testing frequency. RESULTS: The two groups differed in five of the 18 variables examined (P ≤ .001): race (e.g., 60% white vs. 47%), gender (52% male vs. 67%), area of residence (32% downtown Seattle vs. 44%), an HIV test in the previous 12 months (51% vs. 38%). The difference in serologic HIV status was particularly pronounced (4% positive vs. 18%). In four further randomizations, differences in one to five variables attained this level of significance, although the specific variables involved differed. CONCLUSIONS: We found some material differences between the randomized groups. Although the variability of the present study was less than has been reported in serial RDS surveys, these findings indicate caution in the interpretation of RDS results.

Evidence for risk reduction among amphetamine-injecting men who have sex with men; results from national HIV behavioral surveillance surveys in the Seattle area 2008-2012.

In the Seattle area men who have sex with men and also inject amphetamines (amphetamine-injecting MSM/IDU) are disproportionately likely to be infected with HIV. To characterize their distinctive characteristics, we combined data from two Seattle-area surveys of men who have sex with men (MSM) and two surveys of injection drug users (IDU). Amphetamine-injecting MSM/IDU were compared with: male IDU, MSM and other MSM/IDU. Amphetamine-injecting MSM/IDU were older than MSM but younger than IDU, more likely to be white than either group, and had an educational level higher than IDU but below MSM. They had the highest HIV prevalence (56 vs. 4-19 %). However, reported HIV cases among them fell from 92 in 1990 to 25 in 2012. They were most likely to report ten or more sex partners (49 vs. 4-26 %), an STD diagnosis (22 vs. 1-7 %) and be tested for HIV (odds ratio 1.00 vs. 0.34-0.52), and least likely to share needles (odds ratio 1.00 vs. 6.80-10.50). While sexual risk remains high, these data suggest measurable and effective risk reduction with respect to sharing injection equipment and HIV testing among Seattle-area amphetamine-injecting MSM/IDU.

Comparing study populations of men who have sex with men: evaluating consistency within repeat studies and across studies in the Seattle area using different recruitment methodologies.

There is no gold standard for recruiting unbiased samples of men who have sex with men (MSM). To assess differing recruitment methods, we compared Seattle-area MSM samples from: venue-day-time sampling-based National HIV Behavioral Surveillance (NHBS) surveys in 2008 and 2011, random-digit-dialed (RDD) surveys in 2003 and 2006, and STD clinic patient data 2001-2011. We compared sociodemographics, sexual and drug-associated behavior, and HIV status and testing. There was generally good consistency between the two NHBS surveys and within STD clinic data across time. NHBS participants reported higher levels of drug-associated and lower levels of sexual risk than STD clinic patients. RDD participants differed from the other study populations in sociodemographics and some risk behaviors. While neither NHBS nor the STD clinic study populations may be representative of all MSM, both appear to provide consistent samples of MSM subpopulations across time that can provide useful information to guide HIV prevention.

"To share or not to share?" Serosorting by hepatitis C status in the sharing of drug injection equipment among NHBS-IDU2 participants.

BACKGROUND: Persons who inject drugs (PWID) are at high risk for acquiring hepatitis C virus (HCV) infection. The Centers for Disease Control and Prevention estimates there are 17 000 new infections per year, mainly among PWID. This study examines injection equipment serosorting-considering HCV serostatus when deciding whether and with whom to share injection equipment. OBJECTIVE: To examine whether injection equipment serosorting is occurring among PWID in selected cities. METHODS: Using data from the National HIV Behavioral Surveillance System-Injection Drug Users (NHBS-IDU2, 2009), we developed multivariate logistic regression models to examine the extent to which participants' self-reported HCV status is associated with their injection equipment serosorting behavior and knowledge of last injecting partner's HCV status. RESULTS: Participants who knew their HCV status were more likely to know the HCV status of their last injecting partner, compared to those who did not know their status (HCV+: adjusted odds ratio [aOR] 4.1, 95% confidence interval [CI], 3.4-4.9; HCV-: aOR 2.5, 95% CI, 2.0-3.0). Participants who reported being HCV+, relative to those of unknown HCV status, were 5 times more likely to share injection equipment with a partner of HCV-positive status (aOR 4.8, 95% CI, 3.9-6.0). CONCLUSIONS: Our analysis suggests PWID are more likely to share injection equipment with persons of concordant HCV status.

Evaluating consistency in repeat surveys of injection drug users recruited by respondent-driven sampling in the Seattle area: results from the NHBS-IDU1 and NHBS-IDU2 surveys.

PURPOSE: We compared data from two respondent-driven sampling (RDS) surveys of Seattle-area injection drug users (IDU) to evaluate consistency in repeat RDS surveys. METHODS: The RDS-adjusted estimates for 16 key sociodemographic, drug-related, sexual behavior, and HIV- and hepatitis C virus-related variables were compared in the 2005 and the 2009 National HIV Behavioral Surveillance system surveys (NHBS-IDU1 and NHBS-IDU2). Time trends that might influence the comparisons were assessed by the use of data from reported HIV cases in IDU, surveys of needle exchange users, and two previous IDU studies. RESULTS: NHBS-IDU2 participants were more likely than NHBS-IDU1 participants to report older age, heroin as their primary injection drug, male-to-male sex, unprotected sex with a partner of nonconcordant HIV status, and to self-report HIV-positive status. NHBS-IDU2 participants were less likely to report residence in downtown Seattle, amphetamine injection, and a recent HIV test. Time trends among Seattle-area IDU in age, male-to-male sex, and HIV testing could have influenced these differences. CONCLUSIONS: The number and magnitude of the estimated differences between the two RDS surveys appeared to describe materially different populations. This could be a result of changes in the characteristics of Seattle-area IDU over time, of accessing differing subpopulations of Seattle IDU, or of high variability in RDS measurements.

Variations in patterns of sexual risk behavior among Seattle-area MSM based on their HIV status, the HIV status of their partner and partner type.

We evaluated sexual risk behavior in 368 Seattle-area MSM recruited in the 2008 National HIV Behavioral Surveillance survey. We found significant concordance between participants' self-reported HIV status and that of their sexual partners. Persons unaware of partners' HIV status were more likely to report only oral sex. Those aware were less likely to report non-concordant unprotected anal intercourse (UAI). Participants reporting themselves HIV-positive were more likely than those self-reporting HIV-negative status to report non-concordant UAI and several other sexual risk behaviors. The level of non-concordant UAI did not materially differ by whether their partner was a main or casual partner.

Evaluating respondent-driven sampling in a major metropolitan area: Comparing injection drug users in the 2005 Seattle area national HIV behavioral surveillance system survey with participants in the RAVEN and Kiwi studies.

PURPOSE: To empirically evaluate respondent-driven sampling (RDS) recruitment methods, which have been proposed as an advantageous means of surveying hidden populations. METHODS: The National HIV Behavioral Surveillance system used RDS to recruit 370 injection drug users (IDU) in the Seattle area in 2005 (NHBS-IDU1). We compared the NHBS-IDU1 estimates of participants' area of residence, age, race, sex, and drug most frequently injected to corresponding data from two previous surveys, the RAVEN and Kiwi Studies, and to persons newly diagnosed with HIV/AIDS and reported from 2001 through 2005. RESULTS: The NHBS-IDU1 population was estimated to be more likely to reside in downtown Seattle (52%) than participants in the other data sources (22%-25%), be older than 50 years of age (29% vs. 5%-10%), and report multiple races (12% vs. 3%-5%). The NHBS-IDU1 population resembled persons using the downtown needle exchange in age and race distribution. An examination of cross-group recruitment frequencies in NHBS-IDU1 suggested barriers to recruitment across different areas of residence, races, and drugs most frequently injected. CONCLUSIONS: The substantial differences in age and area of residence between NHBS-IDU1 and the other data sources suggest that RDS may not have accessed the full universe of Seattle area injection networks. Further empirical data are needed to guide the evaluation of RDS-generated samples.

Serosorting for hepatitis C status in the sharing of injection equipment among Seattle area injection drug users.

BACKGROUND: Hepatitis C virus (HCV) is a major health problem among injection drug users (IDU). One potential means of reducing risk of HCV transmission among IDU is serosorting, whereby IDU preferentially share injection equipment with persons of like HCV status. METHODS: We surveyed Seattle area IDU recruited by respondent-driven sampling as part of the National HIV/AIDS Behavioral Surveillance system in 2005. RESULTS: Of 337 participants, 91% reported ever having been tested for HCV. Fifty-three percent of participants who shared any injection equipment in the last 12 months reported knowing the HCV status of the last person with whom they shared injection equipment. Thirty-seven percent of self-reported HCV-positive participants reported that their last injection equipment sharing partner was also HCV-positive and 7% reported a HCV-negative partner. Among self-reported HCV-negative participants, 11% reported a HCV-positive partner and 23% a negative partner. The disproportionate tendency to share injection equipment with a partner of like HCV status persisted after control for characteristics associated with HCV positivity in stratified and logistic regression analyses. Among participants sharing injection equipment, 39% reported that they had intentionally shared injection equipment with a partner based on knowledge of their concordant HCV status. CONCLUSIONS: We conclude that a measurable degree of serosorting by HCV status is occurring among Seattle area IDU. Promotion of serosorting among HCV-positive IDU may be a useful harm reduction strategy for IDU who continue to practice sharing injection equipment. If judged efficacious, serosorting would provide a further rationale to encourage and support HCV testing among IDU.

Trends in hepatitis B virus, hepatitis C virus, and human immunodeficiency virus prevalence, risk behaviors, and preventive measures among Seattle injection drug users aged 18-30 years, 1994-2004.

Injection drug users (IDUs) are at risk for infection with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Information on time trends in prevalence of these viruses among IDUs and in behaviors influencing their transmission can help define the status of these epidemics and of public health efforts to control them. We conducted a secondary data analysis combining cross-sectional data from IDUs aged 18-30 years enrolled in four Seattle-area studies from 1994 to 2004. Participants in all four studies were tested for antibody to HIV (anti-HIV), hepatitis B core antigen (anti-HBc), and HCV (anti-HCV), and completed behavioral risk assessments. Logistic regression was used to investigate trends in prevalence over time after controlling for sociodemographic, drug use, and sexual behavior variables. Between 1994 and 2004, anti-HBc prevalence declined from 43 to 15% (p < 0.001), anti-HCV prevalence fell from 68 to 32% (p < 0.001) and anti-HIV prevalence remained constant at 2-3%. Declines in anti-HBc and anti-HCV prevalence were observed within the individual studies, although not all these declines were statistically significant. The declines in anti-HBc and anti-HCV prevalence remained significant after control for confounding. Although we did not observe coincident declines in injection equipment sharing practices, there were increases in self-reported needle-exchange use, condom use, and hepatitis B vaccination. We conclude that there has been a substantial and sustained reduction in prevalence rates for HBV and HCV infection among young Seattle IDUs, while HIV rates have remained low and stable.