Declining prevalence of AIDS-defining illness among newly diagnosed people living with HIV in northern Thailand: a 10-year review

BACKGROUND: HIV infection and AIDS remain serious global health problems. In Thailand, previous studies have revealed that nearly half of newly diagnosed people living with HIV (PLWH) presented with AIDS-defining illnesses (ADIs). However, data regarding the burden of ADIs among PLWH in northern Thailand have been limited. METHODS: This retrospective cohort study analyzed 777 newly diagnosed PLWH between January 1, 2012, and December 31, 2022 at a tertiary care hospital in northern Thailand. RESULTS: The study found that 29.0% of patients presented with ADIs at diagnosis, although this prevalence showed a significant decreasing trend over time (p-value = 0.021). Among the 552 patients without ADIs, 57.2% were asymptomatic at diagnosis. The most common ADIs were pneumocystis pneumonia (42.7%), talaromycosis (27.1%), and pulmonary tuberculosis (14.2%). Median CD4 counts at diagnosis were markedly lower in patients with ADIs [34 (IQR 16-83) cells/cu.mm] compared with those without ADIs [293 (IQR 183-437) cells/cu.mm]. Overall, 25.5% of newly diagnosed PLWH required hospitalization, with rates of 72.0% in those with ADIs and 6.5% in those without. CONCLUSIONS: Despite widespread availability of combination antiretroviral therapy (cART), a substantial proportion of PLWH in northern Thailand continue to be diagnosed at an advanced stage, underscoring the urgent need to strengthen HIV screening and early diagnosis strategies.