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.