Purpose: Understanding the types of individuals and their position in the network may improve interventions for people who inject drugs (PWID).

Methods: From the Transmission Reduction Intervention Project (TRIP), which enrolled PWID and their contacts in Athens, Greece, from 2013 to 2015, we extracted the largest connected component of the network (i.e., the largest group of connected individuals) and identified members who were in the top quartile of the distribution for three network centrality measures: closeness, betweenness, and eigenvector. Using logistic regression, we evaluated associations between high centrality measures and individual sociodemographic characteristics and behaviors. We also varied the definition for high centrality.

Results: Among 231 individuals, 80% were male and between the ages of 25-40 years. Over half of the individuals injected at least once per day, compared to less than daily. Individuals who injected at least once per day were more likely to have high closeness (odds ratio (OR) = 3.36; 95% confidence interval (CI) = 1.57,8.42), high betweenness (OR = 2.22; 95% CI = 1.06,4.67), and eigenvector centrality (OR = 4.50; 95% CI = 1.89,10.68). Individuals who engaged in sex without a condom were less likely to have high closeness (OR = 0.18; 95% CI = 0.07,0.45) or eigenvector (OR = 0.19; 95% CI = 0.07,0.49) centrality.

Conclusions: Individual characteristics and behaviors were associated with centrality and may impact an individual’s position in the network. These associations could be useful in identifying important community members to engage as part of public health initiatives.

Final publication available soon