PHACS uses a “trigger-based” approach in its studies. We want to estimate the prevalence of major abnormalities, or adverse events (AEs), that are potentially related to antiretroviral exposure. However, evaluations are often expensive, invasive to subjects, require specially trained personnel, or may require additional clinic visits.
For this reason, we use a trigger-based approach, which selects a smaller group of targeted “high-risk” study participants and conduct detailed evaluations. This trigger approach improves our ability to detect AEs. It focuses more extensive evaluations on those who might benefit most from identifying AEs.