[Using linear mixed-effects model to analyze the progression of HIV disease, among men who have sex with men].

To understand the progression of CD(4)(+) T cells (CD(4)) declining rate in different age groups among MSM and to further explore the pathogenesis of HIV infection. Data regarding MSM who were diagnosed as HIV positive, aged ≥15 years, with homosexual route of transmission and with more than two records of CD(4) count retained before antiretroviral therapy (ART), were collected from the National AIDS Comprehensive Prevention Information System until May 31, 2019. Linear mixed effect model was used to fit the linear elimination relationship between the square root of CD(4) cell count and infection time before taking up the ART. To get the intercept estimation, we used the results from CD(4) count which containing the dates of last negativity and first positivity on HIV antibody testing. Both test and test were used to test the model parameters. Median intervals from HIV seroconversion to CD(4)<500, <350, <200 cells/μl were estimated. A total of 26 754 individuals were included in the study including 146 of them having records on the last date of being test negative. Their median age was 27 years old (=27, ()-():23-35). The intercept of the liner mixed models among 15-, 25- and ≥35 year olds were 24.84 (95: 23.76-25.92), 23.94 (95: 22.86-25.02), 23.44 (95: 21.91-24.96) and the slope of the liner mixed models among the 15-24, 25-34, 35-44 and ≥45 year olds were -1.31 (95: -1.33--1.25), -1.37(95: -1.40--1.33), -1.53 (95: -1.58--1.47) and -1.59 (95:-1.68--1.51), respectively. Estimation on the median intervals from HIV seroconversion to CD(4) <500, <350, <200 cells/μl counts were 1.29 (95: 0.79-1.81), 3.92 (95: 3.36-4.48) and 7.21 (95: 6.58-7.81), respectively. The median time of 15-24 age group from HIV seroconversion to reach the three CD(4) thresholds appeared the longest, as 1.89 (95: 1.05-2.85), 4.68(95: 3.80-5.77) and 8.17 (95: 7.23-9.42) years, respectively, the median time of ≥45 age group from HIV seroconversion to reach the three CD(4) thresholds appeared the shortest, as 0.68 (95: 0.00-1.72)、2.98 (95: 1.91-4.14)、5.85 (95: 4.62-7.16) years, respectively. Our findings suggested that the CD(4) declining rate had been accelerated along with ageing. Progression time from HIV seroconversion to different CD(4) thresholds appeared different, which was shorter in the older age group. Again, these findings showed the great impact of HIV infection among older age groups in the MSM population. Early diagnosis and treatment were bound to delay the progression of the disease.