Bartlett AW, Lumbiganon P, Jamal Mohamed TA, et al. - Given the vulnerability of perinatally HIV-infected adolescents (PHIVA) to loss to follow-up (LTFU), researchers assessed Asian regional cohort incorporating 16 pediatric HIV services across 6 countries in order to determine the epidemiology and factors for LTFU. LTFU was analyzed through (1) an International epidemiology Databases to Evaluate AIDS (IeDEA) method that determined LTFU as > 90 days late for an estimated next scheduled appointment without returning to care and (2) the absence of patient-level data for > 365 days before the last data transfer from clinic sites. They included 3,509 PHIVA; of these, 275 (7.8%) met IeDEA and 149 (4.3%) met 365-day absence LTFU criteria. Using IeDEA, the cumulative incidence of LTFU was 19.9% and using 365-day absence criteria, the cumulative incidence of LTFU was 11.8%. LTFU was reported across both criteria in correlation to the following risk factors: age at combination antiretroviral therapy initiation < 5 years compared with age ≥ 5 years, rural clinic settings compared with urban clinic settings, and high viral loads compared with undetectable viral loads. Another risk factor identified was age 10–14 years compared with age 15–19 years when 365-day absence criteria were used.