Haber, N., Tanser, F., Bor, J., et al., The Lancet HIV (May 2017), doi:10.1016/S2352-3018(16)30224-7.
This study collected longitudinal, individual-level data on the HIV care cascade to determine where losses in the cascade occur, and to demonstrate differences between longitudinal estimation methods versus standard cross-sectional methods. The authors linked data from longitudinal population health surveillance with local HIV treatment records and examined the data by cascade stage, population stage, and clinical stage; and compared estimates to those obtained from standard cross-sectional data. The findings showed that transition rates varied among different cascade stages. Transition through initial population-based stages—including testing HIV-positive, knowing one’s HIV status, and being linked to care—were significantly slower than transition through clinical stages, particularly the later ones, which include being treatment-eligible, initiating treatment, and demonstrating a successful treatment response. Median transition times from stage to stage were:
- Between testing for HIV and knowing one’s HIV status: 52.1 months
- From HIV status knowledge to care linkage: 52.9 months
- From initiating care to being treatment-eligible: 19.5 months
- From treatment eligibility to treatment initiation: 3.1 months
- From treatment initiation to successful treatment response: 9.3 months.
The authors recommended longitudinal cascade estimation over cross-sectional estimation, because
it captured both cross-sectional data plus changes in cascade progress—although cross-sectional approaches require fewer resources. Cascade estimations should begin with population stages, where bottlenecks in the cascade are greatest.