Challenges in the Evaluation of Interventions to Improve Engagement Along the HIV Care Continuum in the United States: A Systematic Review

Abstract

In the United States (US), there are high levels of disengagement along the HIV care continuum. We sought to characterize the heterogeneity in research studies and interventions to improve care engagement among people living with diagnosed HIV infection. We performed a systematic literature search for interventions to improve HIV linkage to care, retention in care, reengagement in care and adherence to antiretroviral therapy (ART) in the US published from 2007-mid 2015. Study designs and outcomes were allowed to vary in included studies. We grouped interventions into categories, target populations, and whether results were significantly improved. We identified 152 studies, 7 (5%) linkage studies, 33 (22%) retention studies, 4 (3%) reengagement studies, and 117 (77%) adherence studies. 'Linkage' studies utilized 11 different outcome definitions, while 'retention' studies utilized 39, with very little consistency in effect measurements. The majority (59%) of studies reported significantly improved outcomes, but this proportion and corresponding effect sizes varied substantially across study categories. This review highlights a paucity of assessments of linkage and reengagement interventions; limited generalizability of results; and substantial heterogeneity in intervention types, outcome definitions, and effect measures. In order to make strides against the HIV epidemic in the US, care continuum research must be improved and benchmarked against an integrated, comprehensive framework.

Keywords: HIV adherence; HIV care continuum; HIV linkage to care; HIV reengagement; HIV retention in care.

Fig. 1

Schematic of HIV care continuum in the United States indicating steps of interest in review, and summary of outcomes in review. Each box’s area is proportionally sized to the United States population of people living with HIV in 2012 [5, 173]. Boxes representing very small proportions of the population (Newly Diagnosed and Newly in Care) are enlarged for purposes of display. Table displays the continuum steps of interest in review, number of studies included in review (N), NHAS indicator relevant to the continuum step, and a sampling of the outcomes identified in included studies in the review (for full list of outcomes identified, please see Supplemental Table)