Where did they go? Describing and reengaging people with HIV lost to follow-up in the PISCIS Cohort Study.

Reengaging patients lost to follow-up (LTFU) is crucial to achieving the UNAIDS 95-95-95 targets. This study analyses an intervention aimed at identifying and reengaging LTFU individuals in the PISCIS Cohort in Catalonia. The cohort included 28,033 people living with HIV (PLWH) across 17 hospitals in Catalonia and two in the Balearic Islands as of 2021. LTFU was defined as no contact with HIV care in any Catalan hospital for ≥12 months between June 2021 and January 2010. At four hospitals, suspected LTFU cases were confirmed through clinical records and followed up via phone calls, text messages and emails. Confirmed cases were invited to reengage in care. A total of 1,411 suspected LTFU individuals were studied. Compared to those in regular follow-up, LTFU individuals were more often male, aged 30-39, born outside Spain (64.8%) and men who have sex with men (70.4%). Of these, 27.3% could not be located, with a higher proportion born outside Spain (74.8% vs. 61.0%). Reengagement rates were low, though older individuals and women were more likely to reengage. These findings underscore the importance of accurate cohort records, systematic tracking and targeted strategies to reengage hard-to-reach LTFU patients.