Abstract: Objective To explore the epidemic trend characteristics of HIV/AIDS patients ≥50 years old, and to make quantitative predictions to provide scientific reference data for prevention and control,as well as for risk assessment. Method Descriptive epidemiological methods were used to analyze the epidemic trend of newly discovered HIV/AIDS cases aged ≥50 years in Longgang District of Shenzhen from 2018 to 2023, and the grey mean GM(1,1) model was established by buffer operator sequence to determine trend and quantitatively predict. Result From 2018 to 2023, 271 new HIV/ADIS cases aged ≥50 years were found in Longgang District, with an average annual rate of (45±11) cases. The male/female sex ratio was 3.44:1, 62.37% were aged 50 to 59, and the occupations were widely distributed, including housework and unemployment (37.27%) and commercial services (15.87%), 53.51% were married or with spouses, 62.36% had a junior high school education or less, and 81.18% were registered outside the city. Heterosexual transmission (71.22%) was the main route of infection in elderly patients, and non-marital heterosexual contact history was high (63.10%). The main way of detection was found in medical institutions (76.38%). There was no trend in the distribution of HIV/ADIS cases aged ≥50 years in terms of population characteristics, infection routes and sample sources (P>0.05). The proportion of newly discovered cases showed an increasing trend (P<0.005). The established weakening operator GM(1,1) gray model is excellent, with an average relative error of < 2.0%, accuracy >98.0% and development coefficient of 0.05. The number of cases shows an increasing trend, and it is predicted that the annual number of cases aged ≥50 years old may increase from 62 to 75 in 2024-2028. Conclusion The proportion and number of HIV/ADIS cases aged ≥50 in Longgang District showed an increasing trend. Attention should be paid to the epidemic of HIV/ADIS cases aged ≥50 years, and publicity and education should be strengthened to formulate and improve the AIDS prevention and treatment system for the elderly population. The grey GM(1,1) prediction model can be used to determine the epidemic trend and quantitatively predict of HIV/AIDS aged ≥50 years, and has a good guiding significance for the quantitative risk assessment and prevention and control of HIV/AIDS epidemic.

Key words: Human immunodeficiency virus infected/acquired immune deficiency syndrome, Epidemic characteristics, ≥50 years old cases, Grey prediction