Peer influence of injection drug use cessation among dyads in rural eastern Kentucky

Examining the social and behavioral dynamics of substance use in a longitudinal network study in rural Appalachia

BACKGROUND

Prior studies have shown that individuals and their peers often have similar substance use behaviors, but the mechanisms driving these similarities - particularly in rural settings, are not well understood. The primary objectives of this analysis are to (1) identify factors that contribute to relationship turnover and maintenance within a rural network of persons who use drugs (PWUD), (2) determine whether assimilation and/or homophily shape participants use of injection drugs, heroin, and stimulants (methamphetamine and cocaine), and (3) assess the extent that these mechanisms influence networks ties and/or behaviors and whether these effects vary across time.

METHODS

Sociometric network data were collected from a cohort of PWUD in rural Eastern Kentucky at baseline (2008-2010) and at four follow-up visits conducted approximately semiannually. Stochastic actor-oriented models (SAOMS) were used to model network structure and participant behaviors as jointly dependent variables and to identify characteristics associated with the maintenance, dissolution, and formation of network ties and changes in drug use behaviors.

RESULTS

Findings suggest (1) greater network stability over time for reciprocal and transitive relationships, (2) both homophily and assimilation played a greater role in shaping injection drug use (IDU) initiation and cessation than they did in shaping heroin and stimulant use, and (3) the importance of these mechanisms appeared consistent over time.

CONCLUSION

Given the stability of particular network structures and evidence of both homophily and assimilation with respect to drug-use behaviors, interventions that leverage social networks could be used to motivate health-promoting behaviors.

Potential impact of curative and preventive interventions toward hepatitis C elimination in people who inject drugs-A network modeling study

BACKGROUND

Injection-equipment-sharing networks play an important role in hepatitis C virus (HCV) transmission among people who inject drugs (PWID). Direct-acting antiviral (DAA) treatments for HCV infection and interventions to prevent HCV transmission are critical components of an overall hepatitis C elimination strategy, but how they contribute to the elimination outcomes in different PWID network settings are unclear.

METHODS

We developed an agent-based network model of HCV transmission through the sharing of injection equipment among PWID and parameterized and calibrated the model with rural PWID data in the United States. We modeled curative and preventive interventions at annual coverage levels of 12.5 %, 25 %, or 37.5 % (cumulative percentage of eligible individuals engaged), and two allocation approaches: random vs targeting PWID with more injection partners (hereafter 'degree-based'). We compared the impact of these intervention strategies on prevalence and incidence of HCV infections. We conducted sensitivity analysis on key parameters governing the effects of curative and preventive interventions and PWID network characteristics.

RESULTS

Combining curative and preventive interventions at 37.5 % annual coverage with degree-based allocation decreased prevalence and incidence of HCV infection by 67 % and 70 % over two years, respectively. Curative interventions decreased prevalence by six to 12 times more than preventive interventions, while curative and preventive interventions had comparable effectiveness on reducing incidence. Intervention impact increased with coverage almost linearly across all intervention strategies, and degree-based allocation was always more effective than random allocation, especially for preventive interventions. Results were sensitive to parameter values defining intervention effects and network mean degree.

CONCLUSION

DAA treatments are effective in reducing both prevalence and incidence of HCV infection in PWID, but preventive interventions play a significant role in reducing incidence when intervention coverage is low. Increasing coverage, including efforts in reaching individuals with the most injection partners, preventing reinfection, and improving compliance and retention in preventive services can substantially improve the outcomes. PWID network characteristics should be considered when designing hepatitis C elimination programs.

Network centrality and HIV prevention service use among people who inject drugs: Findings from a sociometric network cohort in New Delhi, India

BACKGROUND AND AIMS

Network centrality, an indicator of an individual's importance and potential to drive behavioral change, is rarely used to select peer educators. Individual-level predictors of network centrality might be useful to identify people who inject drugs (PWID) for potential roles as peer navigators or change agents in network-based interventions in settings where sociometric data are unavailable. We assessed the relationship between network centrality and HIV prevention service engagement to determine whether centrally-positioned PWID share measurable commonalities.

DESIGN

Observational study and survey using baseline data from a sociometric network cohort of PWID, enumerated using network software and biometric data (2017-2020). Network ties corresponded to direct injection partnerships in the prior month.

SETTING

New Delhi, India.

PARTICIPANTS

A total of 2512 PWID who were ≥18 years, provided written informed consent, and reported illicit injection drug use within the 24 months before study enrollment.

MEASUREMENTS

Interviewer-administered questionnaires measured demographics and substance use behaviors. Central versus peripheral network position was categorized using betweenness centrality 75th%ile . Logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals (95%CI) between network position and HIV testing, medication for opioid use disorder (MOUD), or syringe service use. Lasso models selected predictors of central network position among 20 covariates detailing demographic, biologic, and substance use information. Predictive accuracy was evaluated using model performance metrics.

FINDINGS

Overall, median age was 26 years (interquartile range 22-34); 99% were male; 628 were classified as central. Compared with PWID at the periphery, central PWID were more likely to use MOUD (aOR: 1.59, 95%CI: 1.30-1.94) and syringe services (aOR: 2.91, 95%CI: 2.25, 3.76) in the prior six months. Findings for HIV testing were inconclusive (aOR: 1.30, 95%CI: 1.00-1.69). The lasso variable selector identified several predictors of network centrality: HIV and hepatitis C infection, number of PWID seen in the prior month, injecting heroin and buprenorphine (vs. heroin only) six months prior, sharing injection equipment six months prior, experiencing drug overdose in the past year, and moderate/severe depression (vs. none/mild). Average agreement between model-predicted vs. observed values was 0.75; area under the receiver operator curve was 0.69.

CONCLUSIONS

In a socioeconomic network of people who inject drugs (PWID) in New Delhi, India, there are common characteristics among individuals based on their network position (central vs. peripheral) but individual-level predictors have only moderate predictive accuracy. Although central network members appear to be more likely to use HIV prevention services than peripheral network members, their potential as change agents may be limited by other factors that impede their ability to adopt or promote HIV prevention service use.

Perceived HIV Treatment Norms Modify the Association Between HIV-Related Stigma and Adherence to Antiretroviral Therapy Among Persons Living with HIV in Baltimore, Maryland

Adherence to antiretroviral therapy (ART) is associated with reduced HIV-related morbidity/mortality and ongoing transmission; however, the extent to which this association is modified by perceived HIV treatment norms is unknown. 270 PLWH completed a survey to assess demographics, risk behaviors, stigma, ART adherence, and perceived HIV treatment norms (Baltimore, 2014-2017). We used modified Poisson regression to examine effect modification by perceived HIV treatment norms. The association between HIV-related stigma and ART adherence was modified by perceived HIV treatment norms. Among individuals who perceived that friends/family were sub-optimally adherent, HIV-related stigma was negatively associated with ART adherence (Adjusted Risk Ratio [ARR] = 0.36; 95%CI 0.15-0.87). Among those who perceived optimal adherence among friends/family, the relationship between HIV-related stigma and ART adherence was not statistically significant (ARR = 1.07; 95%CI 0.65-1.76). Interventions to improve ART adherence among those who are sub-optimally adherent could focus on increasing perceptions of ART adherence among their friends/family.

Exploring the experiences of clients receiving opioid use disorder treatment at a methadone clinic in Kenya: a qualitative study

BACKGROUND

Assessing the experiences of individuals on methadone treatment is essential to help evaluate the treatment program's effectiveness. This study aimed to explore the experiences of patients receiving methadone treatment at a clinic in Nairobi, Kenya.

METHOD

This study employed an exploratory qualitative study design. Through purposive sampling, participants were enrolled from individuals attending a methadone clinic for at least 2 years. Semi-structured individual interviews were used to collect data on substance use and experience before methadone treatment and experiences after starting methadone treatment, including benefits and challenges. Interviews were transcribed, and NVIVO 12 software was used to code the data using the preidentified analytical framework. Thematic analyses were utilized to identify cross-cutting themes between these two data sets. Seventeen participants were enrolled.

RESULTS

Seventeen participants were enrolled comprising 70% males, with age range from 23 to 49 years and more than half had secondary education. The interview data analysis identified four themes, namely: (a) the impact of opioid use before starting treatment which included adverse effects on health, legal problems and family dysfunction; (b) learning about methadone treatment whereby the majority were referred from community linkage programs, family and friends; (c) experiences with care at the methadone treatment clinic which included benefits such as improved health, family reintegration and stigma reduction; and (d) barriers to optimal methadone treatment such as financial constraints.

CONCLUSION

The findings of this study show that clients started methadone treatment due to the devastating impact of opioid use disorder on their lives. Methadone treatment allowed them to regain their lives from the adverse effects of opioid use disorder. Additionally, challenges such as financial constraints while accessing treatment were reported. These findings can help inform policies to improve the impact of methadone treatment.

Patients With Alcohol Use Disorders and Their Concerned Others: Concordance of Lived Experience as a Moderator of Treatment Outcomes

OBJECTIVE

Growing up with an adult with an alcohol use disorder (AUD) is common and negatively affects adult functioning. This study examined two questions concerning the lived experience of growing up in a home with AUD.

METHOD AND RESULTS

The first question asked how adults entering AUD treatment (n = 402) who had this lived experience (58%) compared to those who did not (42%) on indicators of alcohol use severity. Patients with lived experience reported alcohol use at a younger age, more times having been arrested and charged, and greater risk for future substance use. The second question examined concordance between patients and their concerned others on this lived experience (n = 277 dyads) and patients' treatment outcomes 3 months later. The associations between patients' lived experience and better treatment outcomes were stronger when patients' concerned others had a concordant lived experience. When patient-concerned other dyads reported concordant lived experiences at baseline, patients had lower substance use and risk scores at the 3-month follow-up than when the dyads reported discordant lived experiences with regard to growing up in a home with AUD; effect sizes were small.

CONCLUSIONS

Concordance and discordance on this lived experience could be considered in treatment planning for patients with AUD and their concerned others. Providers could ask about each member's childhood and aim interventions at helping dyads discuss their childhoods in ways that validate each other's needs and provide emotional support, without stigmatization. Delivery may consider relationship type (spousal or other) and be in educational or treatment sessions that include the dyad or one member.

Social network predictors of recent and sustained injection drug use cessation: findings from a longitudinal cohort study

BACKGROUND AND AIMS

The US opioid crisis has led to increases in overdose fatalities and the incidence of HIV, hepatitis C and other infections. This analysis examines social network predictors of recent (self-report injection followed by non-injection) and sustained (self-report non-injection at two consecutive visits among those who previously injected) injection cessation in Appalachian Kentucky.

DESIGN

Data were collected through bi-annual longitudinal assessments for Social Networks among Appalachian People (SNAP; 2008-17). Using logistic regression with generalized estimating equations that clustered on individuals, we regressed non-injection status on the number of social network members who (a) did not inject and (b) recently stopped injecting and tested for interactions between each social network exposure and prior non-injection status. Social network exposures were self-reported.

SETTING

Rural eastern Kentucky, USA.

PARTICIPANTS

Participants entered the analysis only after reporting recent injection and had to have had at least two consecutive study visits (n = 326).

MEASUREMENTS

Interviewer-administered surveys collected individual-level socio-demographics, recent (past 6 months) drug use behaviors and the names of recent social support, sex and drug-use partners.

FINDINGS

After adjusting for confounders, the number of non-injecting social network members was positively associated with recent/sustained injection cessation (adjusted odds ratio = 1.27; 95% confidence interval = 1.13-1.42) and having more social network members was associated with reduced odds of recent/sustained injection cessation. The number of previously injecting social network members who had recently stopped injecting was not statistically significantly associated with injection cessation. Neither of the interactions we tested for was statistically significant, suggesting that the relationships may be similar for those who recently stopped injecting versus had not injected for at least 1 year.

CONCLUSIONS

For each additional network member who did not inject drugs, there was an increased odds of recent and sustained injection cessation among people with a history of injection drug use in Appalachian Kentucky.