Effect of homophily amongst opioid dependent HIV-positive individuals under buprenorphine management treatment

Background: ‘Homophily' or similarity of social network members has significant effect on one's health seeking behavior. This paper analyzes the homophily (similarity) and heterophily (dissimilarity) of network members amongst opioid dependent HIV-positive individuals involved in a clinical trial of Buprenorphine management treatment (BMT) in Washington, DC.

Method: Sixty study participants listed their social network members based upon kinship, friendship, trust, support, frequency of contact, and drug use. From participant's knowledge, we further collected data on ties between network members and their socioeconomic and demographic characteristics. The Krackhardt and Stern E-1 Index, which varies between -1 (homophily) to +1 (heterophily) was calculated on a) frequency of contact, b) demographic characteristics, c) criminal activity, d) community ties, e) health status, f) economic status, and g) geographic location. Further, correlation between these indices and clinical outcomes of BMT were evaluated.

Results: Preliminary results show that frequency of contact, friendship, and drug users networks have significant impact on clinical outcomes of i) retention on Buprenorphine, ii) adherence to ART, and iii) viral suppression. For an individual, the effect is strongest when the frequency of contact and the drug user networks overlapped over 70%. As expected, homophily is strong for the kinship networks. Members in the drug users network cluster geographically and are in close proximity to those study participant's with strong homophily.

Conclusion: This study has the potential to identify social network structure and composition to facilitate network based interventions for reducing risk of drug use and increasing retention on HIV treatment.