High HIV incidence density among middle-aged and older populations in Luzhou, China: evidence from retrospective cohort study, 2018–2023

HIV incidence is crucial for monitoring epidemics. This analysis of retrospective, programmatic HIV screening data aimed to estimate HIV incidence density within a repeatedly tested cohort, reflecting new infection detection among individuals who accessed testing services, and to explore associated demographic factors. We analyzed data from 1,863,802 individuals who accessed routine services across all city health facilities, tracking those initially seronegative. The overall incidence density was higher in males (1.21 per 1,000 person-years) than females (0.46), with peaks observed in males aged 70–79 (1.42) and females aged 50–59 (0.72). Cox regression identified demographic characteristics associated with higher incidence: male gender (HR = 2.69, 95% CI: 2.51–2.90), age 50–59 years (HR = 4.19, 95% CI: 2.83–6.21), and widowed/divorced status (HR = 2.01, 95% CI: 1.81–2.22). Higher education was associated with lower incidence (HR = 0.68, 95% CI: 0.52–0.90). The findings highlight a substantial HIV burden among middle-aged and older males, with females in these groups having approximately half the incidence of males. Tailored interventions should focus on these populations, particularly individuals with lower educational attainment and those who are unmarried, divorced, or widowed.