| ObjectiveSichuan Province is one of the provinces with serious AIDS epidemic in China.The number of people who are living with HIV ranks the first in China.In last decade,the number of male cases aged≥50 years old(middle-aged and elderly men,MEM)in newly reported HIV/AIDS cases has increased rapidly,the proportion of new reported cases is also increasing,and its epidemical characteristics,changing trend and risk factors are not clear.This study intends to carry out a comprehensive study on the epidemic situation of MEM in Sichuan Province from the aspects of epidemic characteristics,molecular epidemiological characteristics,risk factors,HIV prevalence and trend prediction,so as to provide data support for the formulation of HIV/AIDS prevention and control strategy among MEM.MethodsHIV/AIDS case reports and follow-up data from January 1,2008 to December 31,2019 were downloaded from the"China Disease Control and prevention information system",newly reported and surviving HIV/AIDS case data of MEM in Sichuan Province were selected according to the time of final adjudication,current address,gender and age,and obtain the data of AIDS surveillance sentinel in Sichuan Province at the same time.The odd months of 2018 and 2019,as well as April 2019,the blood samples of newly reported MEM HIV/AIDS cases were collected for laboratory testing and analysis;the data of population,economy,transportation and medical treatment that may affect the AIDS epidemic from 2008 to 2018 were obtained from Sichuan Provincial Bureau of statistics;the HIV testing data of premarital examination in major maternal and child health care institutions in Sichuan Province were collected.In addition,a cross-sectional study was carried out.SPSS 23.0,Excel and other software were used to clean up and draw charts.α=0.05.(1)Based on the data of reported HIV/AIDS cases among MEM,the distribution,transmission route,late detection and changing trend(Cochran-Armitage test)of the cases were comprehensively analyzed.Arc GIS 10.6 and Arc GIS Pro 2.4 software were used to carry out global and local spatial autocorrelation regression analysis,bivariate autocorrelation analysis,clustering and outlier analysis,and spatiotemporal analysis at the county(district)level,and makes visualization.(2)The number of reported cases in 2019-2022 was forecasted by the ARIMA model.The model was built by SPSS 23.0 software,and SAS9.3 software was used to carry out seasonal decomposition,compare and evaluate the models.The forecated result was verified by the number of reported cases in 2019,then forecasts the number of reported cases in the whole province with the best model,and forecasts the number of reported cases in some key cities(states)with the same method.(3)Based on the data of AIDS surveillance,population data,HIV testing in premarital examination and supervision places over the years in Sichuan Province,the scale of FSW,MSM,IDU,FSW’s clients and other key groups was estimated according to the standard of"National AIDS epidemic estimation data collection and use guideline",Then,using the EPP/Spectrum model and Spectrum 5.3.1 software,we estimated the number of HIV/AIDS survivors and new infections among MEM in Sichuan Province.(4)The newly reported HIV/AIDS cases of MEM in odd months of 2018 and 2019were detected by using the method of LAg-Avidity EIA.The new infection cases within 130 days were found.The proportion of new infection(number of new infections/number of detection),and its distribution characteristics of new infections were analyzed.(5)Using HIV gene extraction,amplification and purification technology,HIV gene sequence of newly reported MEM with HIV/AIDS in April 2019 were obtained.Sequencer 4.9 and Bioedit 7.2 software were used to clean and match the gene sequences.Finally,Fasttree software was used for genotyping.HYPHY software was used to calculate the distance between HIV gene sequences(pairwise distance).The HIV-1 molecular transmission network was constructed by using 1.5%gene distance threshold,and visualized by Cytoscape 3.2.0 software.(6)At the city(profecture)level,we analyzed the relationship between the number of reported cases of MEM and population density(persons/km~2),per capita gross domestic product(Yuan),No.of HIV testing(person-time),highway mileage(km)and the number of medical and health personnel per 10000 permanent residents from2008 to 2018.Building the spatial regression model with Geo Da 1.1.4.0 software,and comparing the ordinary least squares model(OLS),spatial lag model(SLM)and spatial error model(SEM),selecting the best model for correlation analysis finally.(7)A cross-sectional study was carried out to investigate HIV/AIDS cases and AIDS-related behaviors,attitudes and knowledge among general middle-aged and elderly male residents(about 3000).A case-control study was carried out among MEM with newly infected HIV/AIDS cases determined by LAg-Avidity EIA,and ordinary MEM matched by age±1 year old were used as control.Univariate and multivariate logistic regression model were used to analyze the risk factors of HIV infection among MEM by SAS 9.3 software.(8)In the cross-sectional study,the middle-aged and elderly male residents were udnergone the HIV antibody testing,and the≥50 years old male patients who visited the fifteen general hospitals in the survey areas were tested for HIV antibody(the total number was 10500),so as to evaluate the HIV prevalence of MEM.Resluts(1)Characteristics of cases:Between 2008 and 2019,56908 HIV/AIDS cases among MEM were reported in the province,accounting for 26.3%of all newly reported cases.The number of newly reported cases increased from 263 in 2008 to 16017 in 2019,the proportion increased from 3.3%to 42.7%,showing a significant increase trend(Z=120.60,P<0.001),and the reported incidence rate of MEM rose from 1.86/100000 to 147.32/100000.The average age of newly reported cases was 64±9 years old,and the composition of high age group(≥65 years old)showed an upward trend(P<0.001);the occupation was mainly farmers(70.6%),showing an upsurge year by year(Z=40.53,P=0.000);the education level was mainly primary school(53.6%)with an upward trend(Z=15.60,P=0.000);the marital status was mostly married with spouse(54.8%),showing a decrease trend(Z=-6.74,P=0.000);heterosexual transmission was 95.9%,showing an upward trend(Z=35.91,P=0.000);the main form of heterosexual transmission was commercial sexual behavior transmission(69.8%)with an increasing trend(Z=10.29,P=0.000);MEM cases was mainly detected by passive detection,and the detection rate of general hospital was 72.3%;the late detection rate of MEM cases was 44.7%,showing a downward trend(Z=-12.10,P=0.000);the death rate of newly reported MEM cases in the reporting year was 15.0%,showing a downward trend year by year(Z=-25.85,P=0.000),and the main cause of death was AIDS unrelated(70.9%).The component ratio of occupation,route of transmission,education level,marital status,infection rate,heterosexual transmission form and late detection rate had statistic significant(P=0.000)between MEM and young men(20-49 years old)By the end of 2019,there were 45249 MEM living with HIV,accounting for 28.0%of all reported cases.The reported HIV infection rate of MEM was 0.32%.Main route of transmission was heterosexual transmission(93.4%).68.7%of them were farmers.(2)Spatiotemporal distributionGlobal autocorrelation analysis showed that the number of reported HIV/AIDS cases among MEM in Sichuan Province was positive spatial autocorrelation,and increased continuously.The global Moran’s I index increased from 0.15 in 2008 to 0.67 in 2019(all with P<0.001),and the aggregation type belonged to the high value aggregation type(Getis-Ord General G>0 and Z>1.96),The bivariate spatial autocorrelation analysis showed that there was a positive spatial autocorrelation between MEM and the young men in other years except 2008;the local spatial autocorrelation analysis showed that the hot spot appeared in Panxi area of Sichuan from 2008 to 2010,and the number of hot spots was decreasing,and disappeared in 2011;there was no hot spot in Northwest Sichuan,cold spots began to appear in 2012,and continue to expand;hot spots were found in Central Sichuan in 2008,located in Chengdu;in Northeast Sichuan,hot spots were mainly concentrated in the junction of Dazhou and Guang’an(2008-2016),and then disappeared,and sporadic cold spots appeared;in Southeast Sichuan,after the first hot spot appeared in 2010,the number and area of hot spots continued to expand;clustering and outlier analysis(Anselin Local Moran’s I)show that the low-low gathering areas are concentrated in Ganzi and Aba in the northwest of Sichuan,and the high-high gathering areas are scattered in the south,central and northeast of Sichuan between 2008 and 2013,and gradually concentrated to the southeast in 2014 and later;the space-time analysis shows that there are 12different types of spatial-temporal gathering patterns,in which the Consecutive Hot Spots are mainly distributed in the southeast of Sichuan and Chengdu,and the Consecutive Cold Spots are mainly located in Aba and Ganzi Prefecture and the South and North of Sichuan.The Persistent Hot Spots are centralized in the northwest of Chengdu,the Intensifying Hot Spots is Shuangliu,Longquanyi and Xindu of Chengdu,the Historical Hot Spot is located in the east of Guang’an,and the Diminishing Hot Spot is Jinjiang,Chengdu.(3)ARIMA model resultThe model is ARIMA(0,1,1)(0,1,1)12,R~2=0.955,AIC=1538.81,Ljung-box test result showed that the model residuals were randomly distributed(Q=20.48,P=0.200),the model showed that the number of newly reported MEM cases in 2019-2022 with an increasing trend,and the error between the forecasted number of newly reported cases in 2019 and the actual number was 0.3%,the same method was used to predict Chengdu,Zigong,Neijiang,Leshan,Yibin and Liangshan,all showing upward trend.(4)EPP/Spectrum model resultThe fitting results of EPP/Spectrum model showed that the HIV infection rate of IDUs(Liangshan except)showed a decrease trend,while the HIV prevalence of FSW,MSM,FSW’s clients and the general population were on the rise,the estimated number of surviving MEM cases was increasing,with an estimated 54700 cases(95%CI:42100-71800)by the end of 2019,and the detection rate of MEM cases was82.8%,estimation of new infections showed that the number of new HIV infections among MEM is increasing,and the new HIV infection rate of MEM increased from0.63/10000 in 2009 to 5.38/10000 in 2019.(5)Results of new infectionThe total number of cases detected by LAg-Avidity EIA experiment was 13513,accounting for 93.4%of the reported cases.The number of new infection cases was1737,the new infection proportion(NIP)was 12.9%,13.1%in 2018 and 12.7%in2019,without statistically significant(c~2=0.42,P=0.514).Dazhou(19.1%),Mianyang(18.8%),Suining(17.5%)and Ganzi(17.1%)ranked the top five in NIP.The NIP increased with age(Z=4.99,P<0.001),from 11.1%of 50-54 years old to15.7%of 75 years old and above;the NIP of homosexual transmission was the highest(19.1%),and the highest ratio of heterosexual transmission was through non marriage and non-commercial sexual transmission(14.5%),and commercial transmission was 12.4%.The NIP of divorced/widowed people was higher(13.5%),retirees was 16.4%,farmers was 12.3%,and the difference was statistically significant(c~2=16.96,P=0.002).NIP of young men was 11.7%,lower than that of MEM,and the difference was statistically significant(c~2=6.71,P=0.010).(6)HIV-1 gene clusteringIn April 2019,a total of 642 HIV-1 gene sequences were obtained from the newly reported MEM HIV/AIDS cases.The main strain is CRF07＿BC,CRF01＿AE,CRF08＿BC and CRF85＿BC subtypes,the proportion were 46.4%,29.8%,9.2%and7.5%respectively.The overall clustering rate of HIV-1 strains was 45.8%(294/642),and The clustering rate of CRF85＿BC was 72.9%,and the difference of clustering rate among different subtypes was statistically significant(c~2=77.73,P=0.000),a total of 58 clusters were found,the largest cluster contained 78 gene sequences,the largest cluster with CRF01＿AE were from 13 cities in the whole province,and Chengdu was 50.0%.The cluster(35 sequences)formed by CRF85＿BC was mainly from Yibin(88.6%),and the cluster(33 sequences)with CRF08＿BC came from 11cities(prefectures),and Chengdu had the most sequences(30.3%).(7)Risk factors of epidemicAccording to the fitting results of spatial model,the risk factors of OLS model on the number of reported cases of MEM in 2008-2018 were determined.It was found that HIV antibodytesting(2016-2018),population density(2011-2012),per capita GDP(2008-2018),highway mileage(2008-2010,2012-2013 and 2016)were positively correlated with the number of reported cases of MEM,and the number of medical staff per 10000 permanent residents(2008 and 2010-2018)was negatively correlated with it.A total of 242 newly infected MEM cases and 968 ordinary elderly male residents were included in the case-control study.Unconditional multivariate logistic regression analysis showed that married with spouse(OR=0.48,95%CI:0.37-0.64),neutral or opposed to FSW(OR=0.36,95%CI:0.27-0.48),and had more than two ways to acquire AIDS knowledge(OR=0.72,95%CI:0.55-0.94),HIV antibody testing(OR=0.73,95%CI:0.56-0.96),HIV-related knowledge(OR=0.55,95%CI:0.42-0.72)were protective factors of HIV infection among MEM.Living alone/concentrated(OR=1.56,95%CI:1.20-2.04),history of working out(OR=2.10,95%CI:1.61-2.73)and having commercial sex(OR=1.71,95%CI:1.32-2.22)were risk factors.(8)HIV prevalence of MEMIn the cross-sectional survey,a total of 2895 people completed HIV antibody testing,accounting for 96.5%of the total number of people surveyed.Among them,14 people were confirmed HIV infection,and HIV positive rate was 0.48%(95%CI:0.23%-0.74%).1.59%(95%CI:0.50%-2.68%)in Yibin,0.68%(95%CI:0.02%-1.35%)in Zigong,0.33%(95%CI:0.00%-0.80%)in Chengdu,and zero in Guangyuan and Meishan.In hospital HIV antibody testing,the positive rate of HIV was 0.66%(95%CI:0.50%-0.82%),and the positive rates of Yibin,Chengdu,Meishan,Zigong and Guangyuan were 1.54%,0.91%,0.48%,0.34%and 0.10%,respectively.The highest HIV positive rate was 65-69 years old(0.92%).There were statistically significant in the hospital detection results of hospital HIV antibody testing,cross-sectional survey results and reported survival infection rate(c~2=40.60,P<0.001),and the hospital detection results and reported survival infection rate had statistically significant(c~2=38.20,P<0.001).Conclusions(1)MEM has become the key population of AIDS prevention and control in Sichuan Province.The epidemic of AIDS in this population are as follows:heterosexual transmission is the main way of transmission,showing an upward trend;nonmarital heterosexual sex is common,and the proportion of commercial sex is high;main population are low income and low education level;general hospital is the main way of case finding in this group,which belongs to passive detection,high proportion of late detection,and low awareness of active detection.The cases were mainly concentrated in Chengdu and its surrounding areas,and Yibin,Luzhou,Neijiang and Zigong in the southeast of Sichuan.Most of the infections occurred after 50 years old.(2)There are many factors influencing the development of AIDS epidemic and personal infection among MEM.Transportation development,population density,per capita GDP and other factors play a role in promoting the AIDS epidemic;while marital status,access to AIDS knowledge,awareness of HIV active testing,attitude to looking for FSW,acitive awareness of HIV testing,living conditions,migrant work history,non marital heterosexual sex and other factors closely related to the individuals could affect HIV infection.(3)New HIV infections continue to occur among MEM in Sichuan.High risk sexual behaviors are common in MEM,and condom use rate is low.The new infection results show that the new incidenceproportionof cases in MEMis 12.9%,which is higher than that of young men who are in sexually active period,and the NIP increases with age.The EPP/Spectrum model prediction results also show that the number of new infections is increasing.It is necessary to pay attention to the MEM who are unmarried,divorced/widowed,living alone and having a history of working outside,and should strengthen the propaganda and intervention of AIDS to them.(4)The prevention and control of AIDS epidemic among MEM is difficult.There are different subtypes of HIV in MEM in Sichuan.The HIV-1 cluster indicates the association between MEM cases.Two of the clusters involve more than 10 cities(prefectures),and the local report rate of MEM cases is 91.9%,which indicates that the key population(such as FSW)causing MEM infection is mobile;the other cluster is concentrated in Yibin,and also indicates that there is a local aggregation epidemic of AIDS transmission among MEM;the transmission route is mainly through commercial sex,and the proportion of non-married and non-commercial is also high,which brings great challenges to prevention and control of AIDS among this group.(5)The epidemic of AIDS among MEM in Sichuan Province may be further aggravated.From 2008 to 2019,the number of newly reported HIV/AIDS cases in MEM is increasing.ARIMA model predicts that the number of newly reported cases will further increase in the next three years.EPP/spectrum model estimates that the number of MEM HIV/AIDS cases is rising rapidly,the number of new infections is also rising,the HIV prevalence of the general population is rising,and higher in this population. |
PDF Full Text Request