Assisted partner services for people who inject drugs: Index characteristics associated with untreated HIV in partners

Objective: Identify characteristics of persons who inject drugs living with HIV (PWID-LWH) associated with greater assisted partner services (APS) efficiency in identifying partners in need of HIV care and treatment services. Design: Prospective cohort study Methods: PWID-LWH (index participants) were enrolled and asked to provide contact information for sexual and injecting partners who were traced and offered HIV testing. APS efficiency was assessed by the number of indexes needed to interview (NNTI) to find one additional partner who was unaware of their HIV status or not on ART. We defined index participant characteristics associated with greater efficiency, defined as lower NNTIs. Results: Among 783 indexes, the NNTI to identify one partner unaware of their HIV status was 7.1 and to identify one HIV-positive partner not on ART (regardless of status awareness) was 4.1. APS was provided to 977 partners and was more efficient in identifying partners who were not on ART (n=201) among indexes who were female (n=381, 49%; NNTI=2.9 vs. 5.7, p<0.001), unaware of their HIV status (n=74, 9.5%; NNTI=2.2 vs. 4.2, p=0.009), not on ART (n=158, 20%; NNTI=2.1 vs. 4.9; p<0.001), not enrolled in a methadone program (n=604, 77%; NNTI=3.3 vs. 10.4, p<0.001), reporting injecting <5 years (n=441, 56%; NNTI=3.3 vs. 5.0; p=0.005), or from Nairobi (n=452, 58%; NNTI=3.2 vs. 5.6, p<0.001). Conclusions: Scaling up APS among PWID-LWH with certain characteristics could result in more efficient APS and greater partner engagement in HIV care.