Accuracy of name and age data provided about network members in a social network study of people who use drugs: implications for constructing sociometric networks

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.

Methods for Assessing Spillover in Network-Based Studies of HIV/AIDS Prevention among People Who Use Drugs

Human Immunodeficiency Virus (HIV) interventions among people who use drugs (PWUD) often have spillover, also known as interference or dissemination, which occurs when one participant's exposure affects another participant's outcome. PWUD are often members of networks defined by social, sexual, and drug-use partnerships and their receipt of interventions can affect other members in their network. For example, HIV interventions with possible spillover include educational training about HIV risk reduction, pre-exposure prophylaxis, or treatment as prevention. In turn, intervention effects frequently depend on the network structure, and intervention coverage levels and spillover can occur even if not measured in a study, possibly resulting in an underestimation of intervention effects. Recent methodological approaches were developed to assess spillover in the context of network-based studies. This tutorial provides an overview of different study designs for network-based studies and related methodological approaches for assessing spillover in each design. We also provide an overview of other important methodological issues in network studies, including causal influence in networks and missing data. Finally, we highlight applications of different designs and methods from studies of PWUD and conclude with an illustrative example from the Transmission Reduction Intervention Project (TRIP) in Athens, Greece.

Health-based homophily in public housing developments

Public housing residents in the United States face disproportionately high risks for disease, presenting an urgent need for interventions. Evidence suggests interventions leveraging social networks can be successful when relationships are homophilous, as this leads to pooling of risk behaviors among interconnected alters. Yet, we know little about networks of public housing residents. To assess the feasibility of network-based interventions, we investigate the incidence of health-based homophily in public housing developments in Boston, Massachusetts. Employing multilevel models (HLM), we find that respondents report their own health characteristics to be similar to their network partners on oral health, weight, and consumption of sugar-sweetened beverages and foods. We discuss the implications of our findings for health-based interventions in low-income communities.

Extent and implications of omitted ties on network measures in a longitudinal social network survey of people who use drugs

BACKGROUND

Previous research has revealed under-reporting of personal network members (i.e., alters) in studies involving people who use drugs (PWUD). This analysis (1) characterizes relationships that were more likely to be omitted but later recalled with prompting and (2) identifies network structural characteristics most impacted by these omissions among a sample of PWUD in rural Appalachian Kentucky, an epicenter of the opioid epidemic.

METHODS

Data were collected through longitudinal assessments as part of the Social Networks Among Appalachian People (SNAP) study (2008-2017). Study participants completed interviewer-administered questionnaires that collected social network data via free-listing at baseline and six-month intervals. At visit 5, after free-listing, interviewers prompted participants with the names of previously reported alters. We used modified Poisson regression with generalized estimating equations to identify individual- and relationship-level characteristics associated with an alter being reported only after prompting. We examined the impact of including vs. excluding relationships reported after prompting on local and global sociometric network measures (i.e., betweenness centrality, bridging, density, mean degree, transitivity, cliques, and 2-cores).

RESULTS

Relationships reported only after prompting were more likely to be immediate family (Adjusted Prevalence Ratio [APR]:1.29; 95% Confidence Interval [CI]: 1.03-1.63) and less likely to involve sex (APR:0.54; 95% CI: 0.43-0.67). Considerable differences were observed for participant positional rankings of betweenness centrality and bridging, and differences in network density and average degree pre- and post-prompting were statistically significant.

CONCLUSION

Longitudinal network studies that aim to assess transmission dynamics, information diffusion, or peer influence should consider the effects of omitted relationships.

Peer-based Retention Of people who Use Drugs in Rural Research (PROUD-R2): a multisite, randomised, 12-month trial to compare efficacy of standard versus peer-based approaches to retain rural people who use drugs in research

INTRODUCTION

Rural communities bear a disproportionate share of the opioid and methamphetamine use disorder epidemics. Yet, rural people who use drugs (PWUD) are rarely included in trials testing new drug use prevention and treatment strategies. Numerous barriers impede rural PWUD trial engagement and advancing research methods to better retain rural PWUD in clinical trials is needed. This paper describes the Peer-based Retention Of people who Use Drugs in Rural Research (PROUD-R2) study protocol to test the effectiveness of a peer-driven intervention to improve study retention among rural PWUD.

METHODS AND ANALYSIS

The PROUD-R2 study is being implemented in 21 rural counties in three states (Kentucky, Ohio and Oregon). People who are 18 years or older, reside in the study area and either used opioids or injected any drug to get high in the past 30 days are eligible for study inclusion. Participants are allocated in a 1:1 ratio to two arms, stratified by site to assure balance at each geographical location. The trial compares the effectiveness of two retention strategies. Participants randomised to the control arm provide detailed contact information and receive standard retention outreach by study staff (ie, contacts for locator information updates, appointment reminders). Participants randomised to the intervention arm are asked to recruit a 'study buddy' in addition to receiving standard retention outreach. Study buddies are invited to participate in a video training and instructed to remind their intervention participant of follow-up appointments and encourage retention. Assessments are completed by intervention, control and study buddy participants at 6 and 12 months after enrolment.

ETHICS AND DISSEMINATION

The protocol was approved by a central Institutional Review Board (University of Utah). Results of the study will be disseminated in academic conferences and peer-reviewed journals, online and print media, and in meetings with community stakeholders.

TRIAL REGISTRATION NUMBER

NCT03885024.

Privacy and Confidentiality Considerations for Collecting HIV Risk Network Data among Men who Have Sex with Men and Implications for Constructing Valid Risk Networks

Studies aiming to construct risk networks have historically collected network members' names, demographic characteristics and relational data (i.e., type, strength, duration, frequency of interaction, and HIV-related risk behaviors between the pair). Due to difficulties in constructing risk networks stemming from partner anonymity and the use of nicknames, some studies also collect network members' screen names, phone numbers, physical attributes, and scars/tattoos to assist with entity resolution. In-depth interviews with 20 men who have sex with men and transgender women in Kentucky assessed privacy/confidentiality concerns as well as accuracy/recall issues associated with providing these details. Most preferred providing alters' nicknames/first names only or a first name with the first letter of the last name. Many perceived screen names, phone numbers, and scars/tattoos to be too personal/identifying. Willingness to provide more detailed information varied by relationship type/strength, which could influence the validity of the resulting network.

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

BACKGROUND

This analysis aims to assess whether injection drug use cessation among peers predicts injection drug use cessation among individuals and explores whether this association varies by relationship type and strength.

METHODS

Data were collected through baseline and 6-month assessments for the Social Networks among Appalachian People study (2008-2011). Interviewer-administered surveys collected sociodemographic and drug use behaviors (past 6 months and lifetime). Participants also listed sex, drug use, and social support partners (past 6 months). Listed names were cross-referenced with survey participants to identify relationships between study participants. The analytic sample was further restricted to include only those relationship pairs where both individuals reported a history of injection drug use at baseline (n = 244 unique individuals and 746 dyads). We fit a generalized estimating equations logistic regression model to (1) assess the relationship between peer injection cessation and individual injection cessation and (2) determine whether the strength of this association differs by relationship-level variables (i.e., relationship role, relationship type, relationship duration, frequency of interaction, residential proximity).

RESULTS

Overall, those with a network member who ceased injection drug use were more likely to stop injecting over the following 6-month period (AOR=1.65). The magnitude of this association was greater for social support partners (AOR=2.95), family members (AOR=3.56), those with whom the participant interacted at least daily (AOR=2.17), and those who the participant knew longer (AOR=2.09). Further, among family members, the effect size was greater when relationships were further restricted to immediate family members (AOR=5.35).

CONCLUSION

Our findings suggest that in this rural community, closer, more supportive relationships, may be more influential for modeling injection cessation; however, relationship-types were not mutually exclusive so differences in effect size across strata may not be statistically significant. In this setting, social support through the recovery process (including cessation attempts with peers) may increase likelihood of injection cessation.

The Social Context of HIV Prevention and Care among Black Men Who Have Sex with Men in Three U.S. Cities: The Neighborhoods and Networks (N2) Cohort Study

Background: In many parts of the world, stark racial disparities in human immunodeficiency virus (HIV) prevalence, incidence, prevention, and care outcomes persist among gay, bisexual, and other men who have sex with men (MSM), with Black MSM significantly impacted in the United States (U.S.). Individual-level characteristics, including sexual behaviors and socioeconomic status, do not fully account for racial/ethnic disparities in HIV among MSM. We hypothesize that neighborhood contexts and network characteristics influence risk for HIV infection as well as HIV-related prevention and care behaviors. As such, the study design includes the use of real-time geospatial methods and in-depth assessments of multiple network typologies to investigate the impact of neighborhood and network-level factors on HIV prevention and treatment among Black MSM residing in longstanding priority HIV elimination areas in the U.S., namely Chicago, Illinois and in the Deep South (Jackson, Mississippi and New Orleans, Louisiana) (n = 450, n = 50, and n = 100, respectively). We describe the design, sampling methods, data collection, data management methods, and preliminary findings of the ongoing ‘Neighborhoods and Networks (N2) Cohort Study’. Methods/Design: N2 employs a prospective longitudinal design. The sample includes Black MSM participants in Chicago recruited via respondent-driven sampling and assessed every six months over two years of follow-up. Participants enrolled in Jackson and New Orleans are being recruited through existing health and community services and assessed every six months over one year of follow-up. Mobility within and between neighborhoods is being assessed using global positioning system (GPS) technology. Social and sexual networks among Black MSM are being studied through egocentric network inventories as well as newer methods of creating meso-level networks that involve social media (Facebook) and mobile phone contacts. Key HIV prevention outcomes such as pre-exposure prophylaxis (PrEP) care engagement, and HIV/STI (sexually transmitted infections) biomarkers will be examined at baseline and follow-up. Results: As of 31 December 2018, a total of 361 men were enrolled across all study sites: 259 in Chicago and 102 in the Deep South (75 in New Orleans and 27 in Jackson). At baseline, participants ranged in age from 17 to 65 years old (mean = 34.3, standard deviation = 5.1) with 123 men (34.1%) self-reported as HIV positive. While HIV treatment levels were similar between sites, men in the Deep South reported higher rates of adherence than men in Chicago (63.3% versus 49.4%, p = 0.03). Sexual risk profiles were mainly the same between men from different study sites, with 22.9% of men in Chicago and 28.9% in the Deep South reporting consistent condom use during vaginal and anal sex (p = 0.26). Regarding their home neighborhoods, men in the Deep South were more likely than those in Chicago to characterize theirs as having a good reputation (43.1% versus 24.7%, p < 0.001) and as being safe (37.3% versus 21.2%, p = 0.002). Conclusions: The focus on Black MSM in the N2 Study will allow for a nuanced exploration of the attitudes, beliefs, behaviors, and practices of a diverse group of Black MSM. The study is also positioned to provide novel insight about neighborhood and network characteristics that influence HIV-related behaviors. A health equity framework ensures that Black MSM are not explicitly or implicitly deemed as deviant, disordered, or the non-reference group. Findings from N2 will provide guidance for the implementation of more impactful HIV prevention interventions that engage a diverse population of Black MSM as we work toward HIV elimination in the U.S.

Network-Based Research on Rural Opioid Use: an Overview of Methods and Lessons Learned

PURPOSE OF REVIEW

The purpose of this paper is to provide a thorough overview of methods used for recruitment, network data collection, and network data management in a network-based study of rural people who use drugs (PWUD) and to offer methodological recommendations for future research on rural drug use.

RECENT FINDINGS

The Social Networks among Appalachian People (SNAP) study recruited a cohort of 503 rural PWUD via respondent-driven sampling (RDS) and has retained more than 80% of eligible participants over 7-9 years. SNAP has yielded important methodological insights, including that (1) RDS referral was non-random and disproportionately involved kin and (2) interviewer-administered questionnaires were successful in eliciting accurate name and age information about network members. The SNAP experience suggests that RDS was a successful recruitment strategy for rural PWUD and questionnaires administered by community-based interviewers in the context of a Certificate of Confidentiality could elicit detailed data on PWUD risk networks.

Empirical evidence of recruitment bias in a network study of people who inject drugs

Background: Epidemiologic surveys of people who inject drugs (PWID) can be difficult to conduct because potential participants may fear exposure or legal repercussions. Respondent-driven sampling (RDS) is a procedure in which subjects recruit their eligible social contacts. The statistical validity of RDS surveys of PWID and other risk groups depends on subjects recruiting at random from among their network contacts. Objectives: We sought to develop and apply a rigorous definition and statistical tests for uniform network recruitment in an RDS survey. Methods: We undertook a detailed study of recruitment bias in a unique RDS study of PWID in Hartford, CT, the USA in which the network, individual-level covariates, and social link attributes were recorded. A total of n=527 participants (402 male, 123 female, and two individuals who did not specify their gender) within a network of 2626 PWID were recruited. Results: We found strong evidence of recruitment bias with respect to age, homelessness, and social relationship characteristics. In the discrete model, the estimated hazard ratios regarding the significant features of recruitment time and choice of recruitee were: alter's age 1.03 [1.02, 1.05], alter's crack-using status 0.70 [0.50, 1.00], homelessness difference 0.61 [0.43, 0.87], and sharing activities in drug preparation 2.82 [1.39, 5.72]. Under both the discrete and continuous-time recruitment regression models, we reject the null hypothesis of uniform recruitment. Conclusions: The results provide the evidence that for this study population of PWID, recruitment bias may significantly alter the sample composition, making results of RDS surveys less reliable. More broadly, RDS studies that fail to collect comprehensive network data may not be able to detect biased recruitment when it occurs.

Using Network and Spatial Data to Better Target Overdose Prevention Strategies in Rural Appalachia

This analysis uses network and spatial data to identify optimal individuals to target with overdose prevention interventions in rural Appalachia. Five hundred and three rural persons who use drugs were recruited to participate in the Social Networks among Appalachian People Study (2008-2010). Interviewer-administered surveys collected information on demographic characteristics, risk behaviors (including overdose history), network members, and residential addresses. We restricted the sample to individuals with at least one confirmed relationship to another study participant (N = 463). Using dyadic analyses (N = 1428 relationships), we identified relationship-level correlates of relationships with network members who have previously overdosed. We then examined individual- and network-level factors associated with (1) having at least one first-degree alter (i.e., network member) with a prior overdose and (2) each additional network member with a prior overdose (N = 463 study participants). Overall, 28% of the sample had previously overdosed and 57% were one-degree away from someone who previously overdosed. Relationships with those who had overdosed were characterized by closer residential proximity. Those with at least one network member who previously overdosed were more geographically central and occupied more central network positions. Further, the number of network members with an overdose history increased with decreasing distance to the town center, increasing network centrality, and prior enrollment in an alcohol detox program. Because fatal overdoses can be prevented through bystander intervention, these findings suggest that strategies that target more central individuals (both geographically and based on their network positions) and those who have previously enrolled in alcohol detox programs with overdose prevention training and naloxone may optimize intervention reach and have the potential to curb overdose fatalities in this region.

Statistical adjustment of network degree in respondent-driven sampling estimators: venue attendance as a proxy for network size among young MSM

We introduce a new venue-informed network degree measure, which we applied to respondent-driven sampling (RDS) estimators. Using data collected from 746 young MSM in 2014-2016 in Chicago, IL, and Houston, TX, we estimated the population seroprevalence of HIV and syphilis and risk/protective behaviors, using RDS estimates with self-reported network size as a standard degree measure as well as our proposed venue-informed degree measure. The results indicate that the venue-informed degree measure tended to be more efficient (smaller variance) and less biased than the other measure in both cities sampled. Venue attendance-adjusted network size may provide a more reliable and accurate degree measure for RDS estimates of the outcomes of interest.

Overlooked Threats to Respondent Driven Sampling Estimators: Peer Recruitment Reality, Degree Measures, and Random Selection Assumption

Intensive sociometric network data were collected from a typical respondent driven sample (RDS) of 528 people who inject drugs residing in Hartford, Connecticut in 2012-2013. This rich dataset enabled us to analyze a large number of unobserved network nodes and ties for the purpose of assessing common assumptions underlying RDS estimators. Results show that several assumptions central to RDS estimators, such as random selection, enrollment probability proportional to degree, and recruitment occurring over recruiter's network ties, were violated. These problems stem from an overly simplistic conceptualization of peer recruitment processes and dynamics. We found nearly half of participants were recruited via coupon redistribution on the street. Non-uniform patterns occurred in multiple recruitment stages related to both recruiter behavior (choosing and reaching alters, passing coupons, etc.) and recruit behavior (accepting/rejecting coupons, failing to enter study, passing coupons to others). Some factors associated with these patterns were also associated with HIV risk.

A Gold-Standard for Entity Resolution within Sexually Transmitted Infection Networks

Contact tracing for venereal disease control has been widespread since 1936 and relies on reported information about contacts’ attributes to determine whether two contacts may represent the same individual. We developed and implemented a gold-standard for determining overlap between contacts reported by different individuals using cell phone numbers as unique identifiers. This method was then used to evaluate the performance of using reported names and demographic characteristics to infer overlap. Cell-phone numbers, names and demographic data for a sample of high-risk men in India and their contacts were collected using a novel, hybrid instrument involving both cell-phone data extraction and Computer-Assisted Personal Interviewing (CAPI). Logistic regression was used to model the probability that a pair of contacts reported by different respondents were identical, based on the correspondence between their reported names and attributes. A discrete mixture model is proposed which provides predictions nearly as good as the logistic model but may be used in a new population without re-calibration. Despite achieving AUCs of 0.83–0.86, the low rate of true overlap among a very large number of contact pairs still results in a high rate of false positives. Next generation contact tracing calls for more archived or digital matching processes.

Network Research Experiences in New York and Eastern Europe: Lessons for the Southern US in Understanding HIV Transmission Dynamics

PURPOSE

This paper presents an overview of different kinds of risk and social network methods and the kinds of research questions each can address.

RECENT FINDINGS

It also reviews what network research has discovered about how network characteristics are associated with HIV and other infections, risk behaviors, preventive behaviors, and care, and discusses some ways in which network-based public health interventions have been conducted. Based on this, risk and social network research and interventions seem both feasible and valuable for addressing the many public health and social problems raised by the widespread use of opioids in the US South.

Social connectedness is associated with food security among peri-urban Peruvian Amazonian communities

BACKGROUND

Food insecurity is a major global public health issue. Social capital has been identified as central to maintaining food security across a wide range of low- and middle-income country contexts, but few studies have examined this relationship through sociocentric network analysis.

OBJECTIVE

We investigated relationships between household- and community-level social connectedness, household food security, and household income; and tested the hypothesis that social connectedness modified the relationship between income and food security.

METHODS

A cross-sectional census with an embedded questionnaire to capture social relationships was conducted among eleven peri-urban communities. Community connectedness was related to study outcomes of food security and per-capita income through regression models.

RESULTS

Of 1520 households identified, 1383 were interviewed (91.0%) and 1272 (83.9%) provided complete data. Households in the youngest communities had the most total contacts, and the highest proportion of contacts outside of the community. Household income was also associated with more outside-community contacts (0.05 more contacts per standard deviation increase in income, p<0.001).Less food secure households reported more contacts nearby (0.24 increase in household food insecurity access scale (HFIAS) for each additional contact, p<0.001). After adjusting for household-level socioeconomic status, membership in an older, larger, and better-connected community, with a greater proportion of residents engaged in rural livelihood strategies, was associated with greater food security (-0.92 decrease in HFIAS for each one-unit increase in community mean degree, p=0.008). There was no evidence that social connectedness modified the relationship between income and food security such that lower-income households benefited more from community membership than higher-income households.

CONCLUSIONS

Although households reported networks that spanned rural villages and urban centers, contacts within the community, with whom food was regularly shared, were most important to maintaining food security. Interventions that build within-community connectedness in peri-urban settings may increase food security.