Background: The efficacy of pre-exposure prophylaxis (PrEP) is highly dependent on adherence, and one of the main reasons for poor adherence is forgetfulness. Therefore, it is important to explore how to remind users to take their medicine on time. Objective: This study aims to explore the effect of a reminder system on PrEP adherence in men who have sex with men (MSM) to improve adherence. The main function of the reminder system based on the WeChat social media app is to send daily messages to PrEP users reminding them to take their medicine. Methods: An open-label, multicenter, prospective cohort study of PrEP in HIV-negative MSM was conducted from November 2019 to June 2021. Study participants who met the criteria were randomly divided into 2 groups: no-reminder group and reminder group. Both groups received daily oral PrEP with follow-up every 3 months. Adherence was measured on the basis of self-report and was defined as the percentage of medications taken on time. Participants in the reminder group scanned a WeChat QR code and received a reminder message every day. Participants in the no-reminder group took daily oral medicines without reminders. The longitudinal trajectories of adherence for both groups were displayed to compare the variability in adherence at each time point. The association between the changes in adherence (no change, improvement, decline) at each time point and the use of the reminder system was analyzed by multinomial logistic regression models to further explore the effectiveness of the system. Results: A total of 716 MSM were included in the analysis, that is, 372 MSM in the no-reminder group and 344 MSM in the reminder group. Adherence in the no-reminder group fluctuated between 0.75 and 0.80 and that in the reminder group gradually increased over time from 0.76 to 0.88. Adherence at each time point was not statistically different between the 2 groups. Further analysis showed that an improvement in adherence in the early stage was associated with the use of the reminder system (odds ratio [OR] 1.65, 95% CI 1.01-2.70; P=.04). An improvement in average adherence compared to initial adherence was positively associated with the use of the reminder system (OR 1.82, 95% CI 1.10-3.01; P=.02). Conclusions: The effect of the reminder system on PrEP adherence in MSM was more significant in the early stage, which is related to the increased motivation of users and the development of medicine-taking habits. The reminder system is potentially effective for early-stage medicine management, encouraging users to develop healthy medicine-taking habits and to increase their adherence. Trial Registration: Chinese Clinical Trial ChiCTR190026414; http://www.chictr.org.cn/showproj.aspx?proj=35077

Background: Men who have sex with men (MSM) are at high risk for HIV infection and sexually transmitted diseases (STDs). However, there is a lack of accurate and convenient tools to assess this risk. Objective: This study aimed to develop machine learning models and tools to predict and assess the risk of HIV infection and STDs among MSM. Methods: We conducted a cross-sectional study that collected individual characteristics of 1999 MSM with negative or unknown HIV serostatus in Western China from 2013 to 2023. MSM self-reported their STD history and were tested for HIV. We compared the accuracy of 6 machine learning methods in predicting the risk of HIV infection and STDs using 7 parameters for a comprehensive assessment, ranking the methods according to their performance in each parameter. We selected data from the Sichuan MSM for external validation. Results: Of the 1999 MSM, 72 (3.6%) tested positive for HIV and 146 (7.3%) self-reported a history of previous STD infection. After taking the results of the intersection of the 3 feature screening methods, a total of 7 and 5 predictors were screened for predicting HIV infection and STDs, respectively, and multiple machine learning prediction models were constructed. Extreme gradient boost models performed optimally in predicting the risk of HIV infection and STDs, with area under the curve values of 0.777 (95% CI 0.639-0.915) and 0.637 (95% CI 0.541-0.732), respectively, demonstrating stable performance in both internal and external validation. The highest combined predictive performance scores of HIV and STD models were 33 and 39, respectively. Interpretability analysis showed that nonadherence to condom use, low HIV knowledge, multiple male partners, and internet dating were risk factors for HIV infection. Low degree of education, internet dating, and multiple male and female partners were risk factors for STDs. The risk stratification analysis showed that the optimal model effectively distinguished between high- and low-risk MSM. MSM were classified into HIV (predicted risk score <0.506 and ≥0.506) and STD (predicted risk score <0.479 and ≥0.479) risk groups. In total, 22.8% (114/500) were in the HIV high-risk group, and 43% (215/500) were in the STD high-risk group. HIV infection and STDs were significantly higher in the high-risk groups (P<.001 and P=.05, respectively), with higher predicted probabilities (P<.001 for both). The prediction results of the optimal model were displayed in web applications for probability estimation and interactive computation. Conclusions: Machine learning methods have demonstrated strengths in predicting the risk of HIV infection and STDs among MSM. Risk stratification models and web applications can facilitate clinicians in accurately assessing the risk of infection in individuals with high risk, especially MSM with concealed behaviors, and help them to self-monitor their risk for targeted, timely diagnosis and interventions to reduce new infections.

Background: Preexposure prophylaxis (PrEP) is an effective strategy to reduce the risk of HIV infection. However, the efficacy of PrEP is highly dependent on adherence. Meanwhile, adherence changes over time, making it difficult to manage effectively. Objective: Our study aimed to explore and predict the patterns of change in PrEP adherence among men who have sex with men (MSM) and evaluate the impact of the WeChat-based reminder intervention on adherence, thus providing more information for PrEP implementation strategies. Methods: From November 2019 to June 2023, in a randomized controlled longitudinal study of the PrEP demonstration project in Western China (Chongqing, Sichuan, and Xinjiang) based on a mobile health (mHealth) reminder intervention, participants were randomly divided into reminder and no-reminder groups, with those in the reminder group receiving daily reminders based on the WeChat app. Participants were followed up and self-reported their medication adherence every 12 weeks for a total of 5 follow-up visits. We used the growth mixture model (GMM) to explore potential categories and longitudinal trajectories of adherence among MSM, and patterns of change in PrEP adherence were predicted and evaluated based on the decision tree. Results: A total of 446 MSM were included in the analysis. The GMM identified 3 trajectories of adherence: intermediate adherence group (n=34, 7.62%), low adherence ascending group (n=126, 28.25%), and high adherence decline group (n=286, 64.13%). We included 8 variables that were significant in the univariate analysis in the decision tree prediction model. We found 4 factors and 8 prediction rules, and the results showed that HIV knowledge score, education attainment, mHealth intervention, and HIV testing were key nodes in the patterns of change in adherence. After 10-fold cross-validation, the final prediction model had an accuracy of 75%, and the classification accuracy of low and intermediate adherence was 78.12%. Conclusions: The WeChat-based reminder intervention was beneficial for adherence. A short set of questions and prediction rules, which can be applied in future large-scale validation studies, aimed at developing and validating a short adherence assessment tool and implementing it in PrEP practices among MSM.

Background: Gut dysbiosis is observed in men who have sex with men compared with men who have sex with women. However, the association between risk of HIV acquisition and gut microbiota in HIV sero-negative men who have sex with men remains unclear. Methods: We conducted a cross-sectional study in HIV sero-negative men who have sex with men to explore the links between gut microbiota and risk of HIV acquisition. HIV sero-negative men who have sex with men were recruited. Fecal samples were collected for gut microbiota analysis using 16S rRNA gene sequencing. HIV risk assessment tool was used to estimate the risk of HIV acquisition. Latent class analysis was performed to categorize participants into different risk levels. Gut microbiota diversity was analyzed using the R package vegan. Linear discriminant analysis was used to analyze differential taxa between groups. Results: Two independent subgroups were identified. High-risk participants had >2 male partners and mostly engaged in receptive anal intercourse. The high-risk group exhibited significantly higher Shannon index and lower Simpson index, indicating increased gut microbiota diversity. Beta diversity analysis showed significant differences between the high-risk and low-risk groups (F = 2.0245, P = .0369). Linear discriminant analysis revealed differences in the relative abundance of multiple microbial taxa between the 2 groups, with Barnesiella significantly increased in the low-risk group and Roseburia higher in the high-risk group. Conclusions: Risk of HIV acquisition in men who have sex with men is associated with gut dysbiosis, suggesting that gut microbiota may be a potential target for HIV prevention strategies.

Men who have sex with men (MSM) are at high risk for depressive symptoms, partly due to stigma related to both sexual minority status and HIV. In the Chine

The efficacy of Pre-exposure prophylaxis (PrEP) is highly dependent on adherence. This study aimed to explore the factors influencing adherence among men who have sex with men (MSM) and their interrelationships, providing theoretical basis for the development of personalized intervention strategies. The data for this study came from a two-phase study of the PrEP demonstration project conducted among MSM in Western China from 2013 to 2023. Participants were given once-daily oral PrEP medication, with tenofovir disoproxil fumarate (TDF) as the primary active ingredient. Follow-up was conducted at the third-month visit after enrollment, during which self-reported adherence and participant characteristics were collected. Adherence greater than or equal to 80% was considered high level. Candidate predictor variables for high adherence were screened by Least absolute shrinkage and selection operator (LASSO) regression and incorporated into the Bayesian network (BN) used to explore the factors and interrelationships of adherence. A total of 11 variables were significantly associated with high adherence through LASSO regression screening. HIV testing, HIV counseling, HIV knowledge score, perceived the threat of HIV, and high-risk sexual behavior were directly associated with high adherence through BN analysis. According to the BN inference, the probability of high adherence among MSM was estimated to increase by 21% (from a baseline of 63% to 84%) after improving these direct influences; meanwhile, the probability of high-risk sexual behavior also increased by 4% (from a baseline of 68% to 72%). The BN approach provided a new perspective for revealing the factors and intrinsic linkages of adherence among MSM. Achieving early monitoring and probabilistic estimation of adherence and related behavioral patterns will facilitate the identification of individuals in need of enhanced intervention and management.