| Objective:In this study,a CD4 depletion model was firstly constructed by using linear mixed effect model to explore the elimination trend of CD4 cell count with HIV infection time.Through the CD4 depletion model,we explored the distribution of median time from HIV seroconversion to a set of CD4 threshold criteria among HIV infections in different transmission routes and age groups.HIV Trend of new HIV infections in Honghe,Yunnan was estimated based on back-calculation method.Methods:HIV/AIDS cases aged 15 years or above,and reported by May,2019,were selected from the National AIDS Comprehensive Prevention Information System.Those transmitted by mother-to-child route and having less than two records of CD4 cell count testing were all excluded.Linear mixed effect model was used to fit the linear elimination tendency of CD4 cell count with HIV infection time among HIV patients before ART initiation,estimating two parameters(intercept ai and slope bi)of the CD4 depletion model.Based on this CD4 depletion model,we used first CD4 test records of HIV diagnosed cases during 2008-2018 in Honghe to speculate time of HIV seroconversion and distribution of HIV infection year for diagnosed HIV/AIDS cases each year.And we calculated the weight of late diagnosis in terms of the distribution of internals time(Ti)from HIV seroconversion to diagnosis detection.The number of new HIV infections was estimated each year during 2008-2018 by multiplying the number of diagnosed HIV/AIDS cases detected each year by weights of late diagnosis.After speculating the number of new HIV infections in 2017 and before by using the general linear model,the cumulative number of HIV infections in this region and its proportion of detection were both obtained.Results:1.Estimates of the intercept and slope in CD4 depletion modelAmong HIV patients of MSM,the estimated intercept of CD4 depletion model decreased from 24.84(95%CI:23.76 to 25.92)in 15-24y age group to 23.44(95%CI:21.91 to 24.96)in 35y and above age group.The average intercept of their whole age was 24.16(95%CI:23.48 to 24.84).Among those of heterosexually transmitted,the average intercept of the whole age was 23.64(95%CI:22.41 to 24.87)for males,and 22.70(95%CI:21.03 to 24.38)for females.The estimated slope of the model for HIV infections of MSM was-1.31(95%CI:-1.33 to-1.25)in 15-24y age group and-1.59(95%CI:-1.68 to-1.51)in 45y and above,respectively.The average slope across whole age of this population was-1.19(95%CI:-1.41 to-1.37).For patients transmitted by heterosexual behavior,the slope in 15-29y age group for males was-1.21(95%CI:-1.24 to-1.18)and-1.48(95%CI:-1.51 to-1.44)in 40y and above,respectively,and the estimated slope for whole ages groups was-1.32(95%CI:-1.34 to-1.30);the estimated slope was-1.22(95%CI:-1.25 to-1.19)in 15-29y age group and-1.46(95%CI:-1.50 to-1.41)in 40 and above for females,respectively.The estimated slope of whole age groups in heterosexually transmitted patients was-1.29(95%CI:-1.31 to-1.27).Of IDU patients,the average slope for males was-0.92(95%CI:-0.95 to-0.90),and that of females was-1.03(95%CI:-1.09 to-0.98).For patients with other transmission routes,the average slope for males was-1.14(95%CI:-1.22 to-1.06),and that of females was-1.20(95%CI:-1.28 to-1.11).2.The distribution of median time reaching to three CD4 threshold criteriaThe median times from HIV seroconversion to CD4<500,<350,<200 cells/μl among HIV infections of MSM in all age groups were 1.29(95%CI:0.79 to 1.81),3.92(95%CI:3.38 to 4.48),and 7.21(95%CI:6.62 to 7.81)years.For infections of IDU,the median times in males reaching to three CD4 threshold levels were 1.39(95%CI:0.05 to 2.79),5.36(95%CI:3.90 to 6.85),and 10.32(95%CI:8.70 to 11.92)years,while those in females were 0.33(95%CI:0.00 to 2.06),3.88(95%CI:2.13 to 5.79),and 8.31(95%CI:6.32 to 10.45)years.For heterosexual transmitted infections,the median times from HIV seroconversion to reach the three CD4 threshold in males were 0.97(95%CI:0.04 to 1.93),3.74(95%CI:2.76 to 4.74),and 7.20(95%CI:6.17 to 8.25)years,and in women the median times were 0.26(95%CI:0.00 to 1.59),3.09(95%CI:1.77 to 4.47),6.63(95%CI:5.26 to 8.06)years.For infections of other transmission routes,the median times to reach the three CD4 threshold levels from HIV seroconversion in males were 1.12(95%CI:0.04 to 2.37),4.33(95%CI:3.03 to 5.81),and 8.33(95%CI:6.78 to 10.12)years,and in females they were 0.28(95%CI:0.00 to 1.82),3.33(95%Cl:1.81 to 5.11),7.13(95%CI:5.38 to 9.22)years.Thus,the median times to reach different CD4 thresholds for males were longer than did females in HIV infections by any transmission route above.3.The number of new HIV infections and the proportion of detection in HongheThe weight of diagnosis delay decreased from 5.49 in the first year to 1.15 in the eleventh years after HIV seroconversion,and combine with the number of new infections was diagnosed in each year has dropped from 1,432 cases in 2008 to 231 cases in 2018 by the end of 2018,and at the end of 2018,the cumulative number of new HIV infections in Honghe was 35,977,and the proportion of detection was 77.50%,considering the total number of diagnosed HIV/AIDS cases was 27,881 in this region.Conclusion:The CD4 decline rate increased with age among HIV infections of different transmission routes.Comparing with IDU,heterosexual transmission route and others,HIV infections among MSM has a faster CD4 decline rate.For infections transmitted by heterosexual contact,CD4 decline rate in males was faster than that of females.However,those infections of IDU or others had an opposite pattern with a slower decline rate among males than females.The median times from HIV seroconversion to three CD4 threshold levels in younger ages were longer than those of older age groups for each transmission mode group,and for IDU,heterosexual sexual transmission and other routes,those median times were longer for males than females.The number of new HIV infections declined annually.By the end of 2018,three quarters of HIV infections had been detected in Honghe. |
PDF Full Text Request