Addressing the Continuum of Care Among High-risk Thai Men
Phase: NA
Conditions: HIV/AIDS, STD
Sponsor: Mahidol University

Study protocol: Addressing the Continuum of Care Among 
High-risk Thai Men 
 
Authors: Thomas E Guadamuz; Susan M. Kegeles; Lim Sin How; Nattharat Samoh; 
Worawalan Waratworawan; Yamol Kongjareon 
 
IDENTIFIERS 
 
MAHIDOL Ethic Project ID  
2020/121.2605 
Full (Scientific) title 
Addressing the Continuum of Care Among 
High-risk Thai Men 
Study Type 
Interventional 
Target sample size 
600 
STUDY TIMELINES 
 
Study Duration 
01/07/2019-31/05/2024 
Expected Start Date for Cohort Recruitment 
01/06/2020 
End of Study Date 
31/12/2023 
KEY STUDY CONTACTS 
 
1. Assoc. Prof. Thomas E Guadamuz, 
Mahidol Center for Health, Behavior 
and Society Faculty of Tropical 
Medicine, Mahidol University   
2. Professor Susan M. Kegeles, 
University of California, San Francisco 
3. Dr. Lim Sin How, University of Malaya 
4. Nattharat Samoh, Mahidol Center for 
Health, Behavior and Society Faculty 
of Tropical Medicine, Mahidol 
University   
5. Worawalan Waratworawan, Mahidol 
Center for Health, Behavior and 
Society Faculty of Tropical Medicine, 
Mahidol University   
6. Yamol Kongjareon, Mahidol Center 
for Health, Behavior and Society 
Faculty of Tropical Medicine, Mahidol 
University   
 
STUDY SPONSOR 
 
National Institute of Mental Health (NIMH) 
KEY WORDS 
 
YMSM, HIV/AIDS, HUG-M, Mpowerment 
 
 
 

 
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Table of Contents 
Study protocol: Addressing the Continuum of Care Among High-risk Thai Men ................ 1 
1. Introduction ............................................................................................................................. 4 
1.1 Overview of the Problem .................................................................................................. 4 
1.2 Supporting Evidence ........................................................................................................ 4 
1.3 Rationale for This Study ................................................................................................... 4 
1.4 Objective ............................................................................................................................ 5 
2. Study design and methods of data collection ..................................................................... 5 
2.1 Procedures ......................................................................................................................... 6 
2.1.1 Recruitment and Enrollment ......................................................................................... 6 
2.1.2 Data Collection ............................................................................................................. 6 
2.1.3 Retention and Engagement Strategies ......................................................................... 6 
2.2 Eligibility criteria ............................................................................................................... 7 
2.3 Consent .............................................................................................................................. 8 
2.3.1 Consent Procedures ..................................................................................................... 8 
2.3.2 Withdrawal/discontinuation criteria ............................................................................... 8 
2.4 Data analysis ..................................................................................................................... 8 
2.5 Assessment and management of risk ........................................................................... 10 
2.6. Data management .......................................................................................................... 10 
2.7 Recording and reporting of risk events and incidents ................................................ 10 
3. Funding .................................................................................................................................. 11 
4. Monitoring and auditing ....................................................................................................... 11 
5. Publication and dissemination ............................................................................................ 12 
6. References ............................................................................................................................. 12 
7. Annexes ................................................................................................................................. 14 
7.1 Participants information sheet ....................................................................................... 14 
7.2 Consent form ................................................................................................................... 14 
7.3 Statistical Analysis Plan (SAP) ...................................................................................... 14 
 
     
 
 
 
 

 
3 
 
 
 

 
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1. Introduction 
1.1 Overview of the Problem 
Thailand is currently experiencing an alarming HIV epidemic among young men who 
have sex with men (YMSM), particularly those aged 15–29. In Bangkok, HIV prevalence among 
YMSM aged 18–24 is as high as 31%. The HIV incidence rate in this group is approximately 
12%, which is the highest level documented in Asia.1,2 These rates far exceed those in high-risk 
populations in the United States, where even the most at-risk group, Black MSM, has an 
incidence rate of around 4%.3 Contributing risk factors among Thai YMSM include being paid for 
sex, having sex at saunas, and living away from family. The HIV prevalence in northeastern 
provinces like Ubon Ratchathani and Mahasarakham ranges between 10%–25%, which is over 
ten times higher than the national average. If no effective prevention strategies are 
implemented, other regions in Thailand may follow the same trajectory as Bangkok. 
1.2 Supporting Evidence 
Despite the high risk, very few YMSM are accessing HIV testing or care. According to a 
joint study conducted by the US CDC and the Thai Ministry of Public Health, only 50.3% of 
MSM in Thailand had ever been tested for HIV. Of those, merely 24.9% returned for their test 
results. 4 As a result, only 12.5% actually knew their HIV status. 5 Our previous research found 
that 73.3% of YMSM aged 15–19 and 45% of those aged 20–24 had never tested for HIV. 6 This 
indicates that current HIV prevention efforts are failing to reach adolescents and young adults, 
especially in terms of HIV testing and linkage to care. Furthermore, many healthcare providers, 
including HIV test counselors, lack adequate knowledge of the Continuum of Prevention and 
Care (CPC), especially regarding the importance of achieving viral suppression, and often 
perpetuate stigma and discrimination against YMSM. These systemic issues further hinder 
engagement in HIV prevention and treatment services. 
1.3 Rationale for This Study 
To address these urgent gaps, the BAAN HUG-M  intervention was developed as a 
community-based, multi-level approach designed to mobilize YMSM, reduce sexual risk 
behaviors, and improve access to HIV testing and care. Building on the foundation of the 
original HUG-M model, BAAN HUG-M  integrates individual-level behavior change strategies 
with community mobilization and health system strengthening, with a particular focus on the full 
Continuum of Prevention and Care (CPC). The intervention seeks to address structural, social, 
and individual barriers to HIV testing, engagement in care, and achievement of viral suppression 
among Thai YMSM. Thailand offers a unique and timely opportunity to evaluate this 
intervention, owing to its existing public health infrastructure, strong community partnerships, 
and a policy environment conducive to rapid implementation of evidence-based practices. 
Findings from this study could help shape national HIV strategies and inform similar efforts 
throughout Asia and beyond. 

 
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1.4 Objective 
To evaluate the efficacy of Baan HUG-M in decreasing sexual risk behavior; increasing HIV 
testing to at least biannually; and increasing prompt, sustained engagement in care among 
YMSM living with HIV by using a longitudinal cohort of YMSM in Ubon Ratchathani and 
Mahasarakham 
2. Study design and methods of data collection 
This study aims to evaluate the effectiveness of the Baan HUG-M intervention, a 
community-based strategy designed to promote HIV prevention and facilitate access to care 
among young men who have sex with men (YMSM) aged 15 to 29 years. A longitudinal cohort 
design is employed across two geographic locations: Ubon Ratchathani (intervention site) and 
Mahasarakham (control site), with a total sample size of 600 participants (300 per site). The 
follow-up period spans 24 months, with data collection occurring at five time points: baseline 
and months 6, 12, 18, and 24. 
Data collection comprises self-administered surveys completed via the Qualtrics 
platform7 and self-collected biological specimens, including urine samples and rectal swabs, for 
chlamydia and gonorrhea testing. All specimens will be transported to and analyzed at the 
Office of Disease Prevention and Control 10 (ODPC 10), located in Ubon Ratchathani Province. 
Additionally, study data will be linked to the national HIV database maintained by the Ministry of 
Public Health. To protect participant confidentiality, no personally identifiable information is 
collected within the survey. Instead, a Unique Identification Code (UIC) is assigned to each 
participant to enable secure and systematic linkage of data across multiple sources. 

 
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2.1 Procedures 
2.1.1 Recruitment and Enrollment 
Participant recruitment will be conducted over a one-year period using a comprehensive 
outreach strategy encompassing both online and offline channels to reach young men who have 
sex with men (YMSM) in two study locations: Ubon Ratchathani and Mahasarakham. The initial 
target sample size will be 600 participants (300 per province). 
Offline recruitment will involve the distribution of QR codes linking to an online screening 
form. These will be disseminated at public venues and community gathering points frequented 
by the target population, including local markets, university canteens, schools (through 
educational sessions on military conscription), shopping centers, and entertainment venues. 
The research team will also organize community engagement events such as volleyball 
tournaments, photography contests, and cultural festivals (e.g., Mor Lum folk music events), as 
well as outreach activities at bars and clubs popular among YMSM. Collaboration with university 
lecturers, local public health agencies, and public hospitals will support recruitment efforts. 
Online recruitment will be conducted through targeted communication campaigns on 
social media platforms, supplemented by peer-driven outreach activities to increase 
engagement and visibility among potential participants. 
Interested individuals will be required to complete an online eligibility screening form. 
Those who meet the eligibility criteria will receive detailed study information and complete an 
initial electronic consent process. A study team member will then follow up to schedule an 
appointment, during which a comprehensive informed consent discussion will be conducted. 
Written informed consent and a photocopy of the participant’s national identification card will be 
obtained. Participants will then view a demonstration video on how to self-collect rectal swab 
specimens, complete the baseline questionnaire, and provide their first set of biological 
specimens. 
2.1.2 Data Collection 
Data will be collected at five time points: baseline, and months 6, 12, 18, and 24 of 
follow-up. At each round, participants will complete self-administered surveys using tablets or 
smartphones via the Qualtrics platform. A Unique Identification Code (UIC) will be used to 
longitudinally link participant data across time points. The UIC will consist of the first letter of the 
province name, followed by an underscore, the first two letters of the participant’s last name, 
and the date of birth in the DDMMYYYY format (e.g., P_AB01012025). To minimize entry errors, 
local research staff will select the UIC from a predefined list using a forced-choice format. 
At each follow-up round, participants will self-collect biological specimens, including 
urine samples and rectal swabs, for chlamydia and gonorrhea testing. All specimens will be 
transported under temperature-controlled conditions to the Office of Disease Prevention and 
Control 10 (ODPC 10) in Ubon Ratchathani for laboratory analysis. Prior to specimen collection, 
participants will watch a standardized instructional video to ensure correct self-collection 
procedures. 

 
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HIV-related clinical data including the date of the most recent HIV test, HIV status, 
initiation of antiretroviral therapy (ART), treatment continuity, and viral load results will be 
extracted from the national HIV database maintained by the Ministry of Public Health using the 
participant’s national identification number. Access to this database will be restricted to the 
principal investigator and the study statistician to ensure data confidentiality. All data will be 
stored in encrypted and password-protected formats on secure institutional servers. 
2.1.3 Retention and Engagement Strategies 
To promote high retention throughout the study period, the research team will implement 
continuous engagement strategies through digital communication channels, including the LINE 
application, SMS, and phone calls, as well as peer-led community outreach. The team will 
maintain regular contact with participants to provide project updates, appointment reminders, 
and encouragement to take part in each round of data collection. Participants will receive 
ongoing support throughout their involvement in the study to foster motivation and consistency 
in completing questionnaires and providing biological specimens. These combined efforts are 
expected to result in follow-up retention rates of greater than 60% at each follow-up time point. 
2.2 Eligibility criteria 
Inclusion Criteria: 
• Aged between 15 and 29 years 
• Currently residing, studying, or working in either Warin Chamrap District or Mueang 
District of Ubon Ratchathani Province (intervention site), or in Kantharawichai District or 
Mueang District of Mahasarakham Province (control site) 
• Intend to remain in the study area for at least the next three years 
• Assigned male at birth 
• Self-identify as gay, men who have sex with men (MSM), bisexual, or toot (a locally 
understood term) 
• Have engaged in anal sex (insertive or receptive) with a male partner within the past 12 
months 
• Willing and able to provide informed consent to participate in the study 
Exclusion Criteria: 
• Aged ≤14 years or ≥30 years 
• Not currently residing, studying, or working in one of the designated study areas 
• Planning to move out of the study area within the next three years 
• Assigned female at birth 
• Self-identify as a woman, transgender woman, or transfeminine individual 
• Unwilling to participate in follow-up activities associated with the study 
 

 
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2.3 Consent 
2.3.1 Consent Procedures 
All participants will provide written informed consent at the time of enrollment. For 
participants under the age of 18, a waiver of parental consent will be obtained from the ethics 
committee to protect them from the risk of involuntary disclosure of their sexual orientation or 
HIV status. Prior to enrollment, participants will receive a study information sheet in advance. 
On the scheduled enrollment day, the document will be provided again, and participants will 
have the opportunity to review it with the support of field staff. 
To ensure full comprehension of study procedures, multiple formats will be used, 
including printed materials, instructional videos (e.g., on self-collection of biological specimens), 
and verbal explanations by trained personnel. Participants will be encouraged to ask questions 
about any aspect of the study, including the survey process, biospecimen collection, and their 
right to withdraw at any time. Informed consent will only be obtained after participants 
demonstrate understanding and express willingness to participate. 
Additionally, at each follow-up visit, field researchers will reassess participants’ 
understanding of the study and reconfirm their voluntary participation. This will include obtaining 
verbal reconfirmation before completing questionnaires and providing biological specimens, to 
ensure that participants remain informed and continue to consent throughout the longitudinal 
study. 
2.3.2 Withdrawal/discontinuation criteria  
Participants could withdraw from the study at any time and for any reason. Withdrawal 
did not affect the compensation they had already received or their access to HIV-related 
services. Common reasons for discontinuation included relocation, being unreachable, or 
unwillingness to continue participation. 
2.4 Data analysis 
Both descriptive and inferential statistical methods will be employed to evaluate the 
effectiveness of the Baan HUG-M intervention over the study period. Analyses will compare the 
intervention group (Ubon Ratchathani) and the control group (Mahasarakham) across 
demographic variables, behavioral measures, and health-related outcomes associated with HIV 
and sexually transmitted infections (STIs). 
2.4.1 Descriptive Analyses 
Baseline demographic, behavioral, and health characteristics of participants will be 
summarized using descriptive statistics, stratified by study arm (intervention vs. control). 
Comparisons will be made between the two study sites (Ubon Ratchathani as the intervention 
site, and Mahasarakham as the control site) to assess initial differences and changes over time. 
Categorical variables will be presented as frequencies and percentages. Continuous variables 
will be summarized using means and standard deviations, or medians with interquartile ranges 
(25th to 75th percentile), depending on data distribution. 

 
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2.4.2 Primary and Secondary Outcome Analyses 
To evaluate the effects of the intervention over time, Generalized Estimating Equations 
(GEE) with appropriate link functions will be applied (e.g., logit for binary outcomes and identity 
for continuous outcomes). The models will include study arm, time (follow-up round), and their 
interaction to estimate the effect of the intervention across time points. Robust standard errors 
will be used to account for within-subject correlation due to repeated measurements. For 
incidence outcomes (e.g., HIV, chlamydia, and gonorrhea infections), person-time will be 
calculated, and incidence rate ratios (IRRs) with 95% confidence intervals will be reported. 
2.4.3 Multiple Comparisons and p-value Adjustment 
When multiple comparisons are made, such as in subgroup analyses or secondary 
outcomes, adjustments to p-values will be considered to control for the risk of type I error. 
Methods such as Bonferroni correction or false discovery rate (FDR) adjustment will be applied 
as appropriate. 
2.4.4 Statistical Software 
All data analyses will be conducted using STATA version 18.0 8, which is the primary 
statistical software used by the research team for data management, descriptive analyses, 
regression modeling, and longitudinal data analysis. 

 
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2.5 Assessment and management of risk 
This study will be conducted as a low-risk observational cohort study. However, certain 
survey items such as those related to sexual behavior and HIV status may be considered 
sensitive. To minimize potential risks, several protective measures will be implemented. All 
surveys will be administered anonymously, and data will be stored securely using encrypted 
systems with restricted access, ensuring that no personally identifiable information is collected. 
Participants will be informed of their right to skip any question they find uncomfortable 
and their right to withdraw from the study at any time without any negative consequences. Field 
researchers will be available throughout the study to provide support, clarify procedures, and 
address any concerns. Participants will also be referred to mental health or HIV-related services 
as appropriate. 
In addition, participants who are diagnosed with a sexually transmitted infection such as 
chlamydia or gonorrhea will receive preliminary counseling and will be referred to appropriate 
healthcare facilities for further examination and treatment, in accordance with Ministry of Public 
Health guidelines. 
Furthermore, a Data and Safety Monitoring Board (DSMB) will be established to oversee 
the study’s risk mitigation strategies and ensure the ongoing protection of participant safety and 
well-being. The DSMB will also be responsible for monitoring ethical compliance, providing 
independent review of study procedures, and advising the research team on any necessary 
protocol modifications to uphold ethical and safety standards throughout the study. 
2.6. Data management 
Data will be collected using the Qualtrics platform, with force-response enabled for 
critical items and programmed skip logic applied where appropriate. After data collection, 
datasets will be exported, cleaned, and processed using STATA. 
Participant data across follow-up rounds will be linked using a Unique Identification Code 
(UIC) and, for data retrieved from the Ministry of Public Health, the national identification 
number. All personally identifiable information will be protected through double encryption and 
securely stored on password-protected servers hosted at Mahidol University. Access to these 
data will be restricted to authorized personnel only, including the Principal Investigator (PI) and 
designated data managers. 
2.7 Recording and reporting of risk events and incidents 
In the event that an adverse or risk-related incident occurs during the study, the research 
team will document and review the incident systematically. Key information such as the nature 
of the incident, time of occurrence, individuals involved, and any immediate actions taken will be 
recorded. 
The research team will assess the severity of the incident and determine appropriate 
follow-up measures. Incidents considered serious or potentially affecting the safety and well-
being of participants will be promptly reported to the Data and Safety Monitoring Board (DSMB) 
for independent review and recommendations. Such incidents will also be reported to the 
Institutional Review Board (IRB) within the required timeframe in accordance with ethical 
guidelines. 

 
11 
The research team has clear procedures in place to respond to such incidents in a 
timely, transparent, and appropriate manner. All incident records will be stored securely and 
treated as confidential. Participants will also be able to report any concerns or discomfort 
through confidential communication channels available throughout the duration of their 
participation in the study. 
3. Funding 
This study is funded by the National Institute of Mental Health (NIMH), under Grants 
R01MH119015. 
4. Monitoring and auditing 
The Principal Investigator (PI) will be responsible for overseeing the overall 
implementation of the study and ensuring adherence to the approved protocol and ethical 
standards. In addition, two Project Managers will be assigned to supervise and coordinate 
different study components, with one responsible for the intervention arm and the other for the 
control group, to ensure fidelity to procedures and consistency across study sites. 
Local implementation and data collection activities will be supported by provincial-level 
advisors, including representatives from provincial hospitals and Provincial Public Health Offices 
who will assist in monitoring field operations and ensuring data quality in their respective 
provinces. 
A Community Advisory Board (CAB) will be engaged to provide guidance on participant 
recruitment strategies and the implementation process, ensuring community involvement and 
cultural appropriateness throughout the study. 
Internal monitoring will be conducted regularly by the core study coordination team to 
verify data accuracy, review informed consent procedures, and ensure compliance with study 
protocols, including biospecimen handling and confidentiality safeguards. 
The Data and Safety Monitoring Board (DSMB) will conduct independent reviews of 
study progress, risk events, and participant safety data on a scheduled basis. Additionally, 
representatives from the Institutional Review Board (IRB) or study sponsors may perform audits 
to assess protocol compliance, ethical conduct, and data integrity. 
All findings from monitoring and auditing activities will be recorded, and any deviations 
from the protocol will be addressed through corrective actions. Reports will be submitted to the 
IRB and DSMB as required, and follow-up actions will be tracked to ensure continuous quality 
assurance throughout the study. 

 
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5. Publication and dissemination 
The findings from this study will be disseminated through a range of channels to ensure 
impact at both academic and programmatic levels. Results will be published in peer-reviewed 
journals and presented at national and international conferences to contribute to the scientific 
knowledge base. All publications will adhere to ethical guidelines, ensuring the confidentiality of 
participants and transparent reporting of both positive and negative outcomes. 
In addition to academic dissemination, the study team will share summary findings with 
key stakeholders, including local health authorities, service providers, NGOs, and community-
based organizations. Plain-language summaries will be prepared where appropriate to enhance 
accessibility among non-academic audiences, including community members and local 
decision-makers. 
Given the intervention-focused nature of the study, particular attention will be given to 
engaging multi-sectoral partners in the study areas to support the refinement and potential 
scale-up of effective components. Collaboration will include government agencies, the public 
health system, local NGOs, and community networks. These partnerships are intended not only 
to support the implementation of the intervention but also to foster sustainability and integration 
into existing systems beyond the research period. 
A Community Advisory Board (CAB) will be consulted in the development of community 
dissemination strategies to ensure that findings are returned in a culturally appropriate and 
meaningful manner. Authorship on all publications will be determined based on substantial 
contributions, following international authorship guidelines (e.g., ICMJE). All dissemination 
activities will be reviewed and approved by the Principal Investigator.  
6. References 
 
1. van Griensven F, Thienkrua W, McNicholl J, et al. Evidence of an explosive epidemic of HIV 
infection in a cohort of men who have sex with men in Thailand: AIDS. 2013;27(5):825-832. 
doi:10.1097/QAD.0b013e32835c546e. 
2. Thai National AIDS Committee. Thailand AIDS Response Progress Report 2015. Reporting 
Period: 2012-2013. Vol 2014. Thailand Ministry of Public Health 
3. Stall R, Duran L, Wisniewski SR, et al. Running in Place: Implications of HIV incidence 
estimates among urban Men Who Have Sex with Men in the United States and other 
industrialized countries. AIDS Behav. 2009;13(4):615-629. doi:10.1007/s10461-008-9509-7. 
4. Wimonsate W, Naorat S, Varangrat A, et al. Factors associated with HIV testing history and 
returning for HIV test results among Men Who have Sex with Men in Thailand. AIDS Behav. 
2011;15(4):693-701. doi:10.1007/s10461-010-9755-3. 
5. Weiss KM, Jonas KJ, Guadamuz TE. Playing and never testing: Human Immunodeficiency 
Virus and sexually transmitted infection testing among app-using MSM in Southeast Asia. Sex 
Transm Dis. 2017;44(7):406-411. doi:10.1097/OLQ.0000000000000624. 
6. Griensven F van, Phanuphak N, Srithanaviboonchai K. Biomedical HIV prevention research 
and epidemic control in Thailand: Two sides of the same coin. Sex Health. 2014;11(2):180-199. 
doi:10.1071/SH13119 

 
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7. Qualtrics. Qualtrics XM Platform™ [Survey Software]. Provo (UT): Qualtrics; 2024. Available 
from: https://www.qualtrics.com 
8. StataCorp. Stata Statistical Software: Release 18. College Station (TX): StataCorp LLC; 
2023. 
 
 

 
14 
7. Annexes 
7.1 Participant Information Sheet 
 
 Participant Information Sheet and Informed Consent Form for Survey Participation  
Note: This document may contain information that you do not fully understand. Please ask the 
principal investigator or their representative to explain it to you until you are completely 
clear.  
Study Title 
Addressing the continuum of care among high-risk Thai 
Principal 
Investigator 
Associate Professor Dr. Thomas Guadamuz 
Affiliation: 
Faculty of Social Sciences and Humanities, Mahidol University 
Contact 
Numbers 
During office hours: 02 441 9184, After hours: 086 084 4154 
Study Sites: 
Maha Sarakham Province and Ubon Ratchathani Province, Thailand 
Funding 
Agency 
National Institutes of Health (NIH), United States 
 
Project Summary: This research project aims to: 1. Explore the sociocultural contexts related 
to risk behaviors and access to health services among young men who have sex with men 
(YMSM), in order to develop culturally appropriate health promotion and HIV prevention 
interventions that align with the lived experiences of youth. 2. Implement intervention activities 
designed to increase the rate of HIV testing and regular retesting among YMSM, as well as 
improve access to antiretroviral therapy (ART) and continuous HIV care among HIV-positive 
youth. The project will include both intervention and control provinces. 3.Compare knowledge, 
prevention practices, HIV testing behaviors, and access to HIV treatment among YMSM across 
the two study sites (intervention vs. control), in order to evaluate the effectiveness of the 
intervention activities conducted in the intervention site. 
You are invited to participate in this study because you identify as a man who has sex with 
men (MSM), are between the ages of 18 and 29, and reside in one of the study sites selected by 
the researchers. 
 
Total number of study participants 300 participants per province (600 participants in total) 
 
The total duration of the study is 3 years (June 2020 – May 2023) 

 
15 
 
If you agree to participate in this research study, the researchers will ask you to: 
1. You will be asked to complete a questionnaire on your electronic device via a link sent to you 
through the contact method you provide. The questionnaire consists of nine sections: (1) 
demographic information, (2) sexual behaviors, (3) HIV status, (4) sexually transmitted 
infections, (5) substance use, (6) PEP and PrEP, (7) mental health, (8) social stigma, and (9) 
social support. The questionnaire contains approximately 94 items and will take about 15 
minutes to complete. You will be asked to complete this questionnaire five times over a three-
year period, once every six months. 
2. You will be asked to undergo testing for sexually transmitted infections once per year for three 
years. This includes testing for gonorrhea and chlamydia, using self-collected specimens from 
the rectum and urine. The study team will send you the testing kits and provide your results. If 
you are diagnosed with a sexually transmitted infection, field staff will assist you in accessing 
appropriate treatment in accordance with your healthcare coverage. 
3. If you are a person living with HIV, the research team will request your permission to access 
your treatment records, including your viral load and CD4 results, as well as records of screening 
and treatment for sexually transmitted infections. 
Ø The information you provide through the questionnaire will be recorded using a code in 
place of your name and personal details. All personal data and any other information related to 
you will be destroyed after the completion of the study. 
Ø  While participating in this research, you may feel uncomfortable or distressed by some 
of the questions. You have the right to skip any question that you do not wish to answer. You 
also have the right to withdraw from the study at any time without prior notice. Choosing not to 
participate or deciding to withdraw from the study will have no negative consequences for you in 
any way. 
Ø Your personal information will be kept confidential and will not be disclosed to the public 
in any individually identifiable form. Research findings will be reported in aggregate form only. 
Access to your information will be limited to members of the research team and the Human 
Research Ethics Committee. 
Ø You will receive a compensation of 300 Baht for each participation in this study. 
Ø If you have any questions regarding this research study, you may contact the Principal 
Investigator, Associate Professor Dr. Thomas Guadamuz, at 02 441 9184 during office hours or 
086 084 4154 outside office hours. 
Ø This research study has been approved by the Committee for Research Ethics (Social 
Sciences), Mahidol University. The committee office is located at the Faculty of Social Sciences 

 
16 
and Humanities, Mahidol University, Phutthamonthon Sai 4 Road, Salaya Subdistrict, 
Phutthamonthon District, Nakhon Pathom 73170. Telephone: 0 2441 9180, Fax: 0 2441 9181. If 
you feel that you have not been treated in accordance with what has been described in this 
document, you may contact the Chair of the Ethics Committee or their representative at the 
address and telephone number provided above. 
 
Thank you for taking the time to complete the questionnaire. 
Sincerely, 
Associate Professor Dr.  Thomas Guadamuz 
 
 

 
17 
7.2 Consent Form 
Form of Informed and Voluntary Consent to Participate in Research 
 
 
                                                   Participant Information 
 
Date ........... /........... /............ 
Full Name 
 
Age  
years 
House Number 
 
Street 
 
Subdistrict  
 
District 
 
Province 
 
Postal Code 
 
Phone Number 
 
 
I hereby express my consent to 
participate as a subject in the 
research project entitled 
Addressing the continuum of care among high-risk Thai 
 
I have been fully informed of the research project’s background and objectives, the 
details of procedures I will undertake and receive, the expected benefits of the research, and 
any potential risks that may arise from participating in the study, as well as the measures in 
place to prevent and manage such risks. I have thoroughly read the information sheet provided 
to research participants, received sufficient explanations, and had my questions answered by 
the principal investigator. 
 
Therefore, I voluntarily agree to participate in this research project. 
 
I understand that I have the right to request further information regarding the benefits and 
potential risks of participating in this study, and that I may withdraw or decline to participate at 
any time without any consequences to my access to current or future healthcare or services. 
 
I consent to the research team’s use of my personal data, including access to my HIV 
treatment records (if I am a person living with HIV) or records related to sexually transmitted 
infection (STI) treatment (if I am diagnosed with an STI). I understand that my confidentiality will 
be strictly protected, and my identity will not be disclosed. Research findings will be reported 
only in aggregate form and not at the individual level. 
 
If I have any questions regarding the study, I may contact Associate Professor Dr. 
Thomas Guadamuz at 086 084 4154 or 086 690 0850 at any time. 
 
If I believe that I have been treated in a manner inconsistent with what is described in the 
information sheet, I may contact the Chair or representative of the Committee for Research 
Ethics (Social Science) at the Office of the Ethics Committee for Human Research, Faculty of 
Social Sciences and Humanities, Mahidol University, Phutthamonthon Sai 4 Road, Salaya 
Subdistrict, Phutthamonthon District, Nakhon Pathom 73170, Tel: 02 441 9180, Fax: 02 441 
9181 during official working hours. 
 
I thoroughly understand the statements in the information sheet for the research subjects and 
in this consent form. I thereby give my signature. 
 
Signature...................... Participant Signature......................... Research staff obtaining consent 
(..............................................) 
 
 
(...........................................) 
Date.......................................... 
                   Date............................................ 
 
 

 
18 
7.3 Statistical Analysis Plan (SAP) 
 
Study Title: Addressing the Continuum of Care Among High-risk Thai Men 
ClinicalTrials.gov Identifier (NCT Number): NCT05161689 
Document Date: 01/01/2020 
 

 
19 
1. Introduction 
1.1 Objectives of the Statistical Analysis Plan 
The primary objective of this Statistical Analysis Plan (SAP) is to prospectively define the 
analytical framework, statistical methods, and procedures that will be used to analyze data from 
the clinical study titled “Addressing the Continuum of Care Among High-risk Thai Men”. This 
SAP is designed to ensure that the analysis is transparent, reproducible, and aligned with the 
registered study protocol under ClinicalTrials.gov Identifier NCT05161689. 
This SAP is intended to: 
• 
Describe the planned analyses for the primary and secondary study objectives 
• 
Specify the statistical techniques and data handling procedures to be used 
• 
Define the analysis populations 
• 
Outline approaches to address missing data, conduct sensitivity analyses, and 
implement subgroup analyses 
1.2 Background and Significance of the Study 
This study aims to evaluate the efficacy of the BAAN HUG-M intervention in: 
• 
Reducing sexual risk behaviors 
• 
Increasing the frequency of HIV testing (at least biannually) 
• 
Promoting prompt and sustained engagement in HIV care 
The study is conducted through a longitudinal cohort of young men who have sex with men 
(YMSM) (“YMSM Cohort”, N = 600) residing in Ubon Ratchathani (intervention site) and 
Mahasarakham (control site). Given the disproportionate burden of HIV among YMSM in 
Thailand, and the structural and behavioral barriers to care, this study addresses a critical public 
health challenge with implications for national HIV policy and intervention programming.1-3 
2. Study Design Overview 
This will be a prospective, longitudinal cohort study involving 600 young men who have 
sex with men (YMSM) aged 15–29 years, with equal allocation to two study sites: 
• 
Intervention city: Ubon Ratchathani (n = 300) 
• 
Control city: Mahasarakham (n = 300) 
Participants will be followed for 24 months, with data collection scheduled at five time 
points: baseline, 6 months, 12 months, 18 months, and 24 months. 
 
Data Collection and Sources 
Data will be collected through online self-administered questionnaires hosted on the 
Qualtrics platform and completed using tablets or smartphones. To ensure anonymity while 
enabling longitudinal data linkage, no personal identifiers will be recorded. Instead, participants 
will enter a Unique Identification Code (UIC) at each round of data collection. 
 
 
 
Retention and Follow-up 
To promote high retention throughout the study period, the research team will implement 
continuous engagement strategies via digital platforms and peer-led community outreach. 
These efforts are expected to result in follow-up retention rates of greater than 60% at each 
follow-up time point. 

 
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3. Study Objectives and Endpoints 
3.1 Primary Objective 
To evaluate the effectiveness of the BAAN HUG-M intervention in increasing access to 
and engagement with the intervention activities, and in promoting HIV testing uptake among 
young men who have sex with men (YMSM) who have never previously been tested for HIV. 
3.2 Secondary Objectives 
• 
To evaluate the effect of the intervention on reducing HIV incidence. 
• 
To evaluate the effect of the intervention on reducing the incidence of chlamydia 
trachomatis and gonorrhea infections. 
• 
To evaluate the effect of the intervention on reducing sexual risk behaviors (e.g., 
condomless anal intercourse). 
• 
To evaluate linkage to and retention in HIV care among HIV-positive participants, 
including the proportion with undetectable viral load. 
• 
To evaluate the uptake of pre-exposure prophylaxis (PrEP) among HIV-negative 
participants. 
3.3 Primary Outcome 
• 
HIV testing uptake: 
Proportion of participants who report having ever tested for HIV during the 24-month 
follow-up period. Data will be collected from HIV testing records provided by the Ministry 
of Public Health national database. 
3.4 Secondary Outcomes 
• 
HIV incidence: 
Number of new HIV infections per 100 person-years, based on seroconversion during 
follow-up, using data from the Ministry of Public Health national HIV database. 
• 
Incidence of Chlamydia and Gonorrhea infections: 
Number of new chlamydia and gonorrhea infections identified at each follow-up round, 
based on self-collected urine and anal specimens. 
• 
Sexual risk behavior: 
Proportion of participants reporting condomless anal intercourse with male partners in 
the past 6 months, measured via self-reported survey data. 
• 
Retention in HIV care: 
Proportion of HIV-positive participants who remain engaged in HIV care at months 6, 12, 
18, and 24, based on data from the Ministry of Public Health national database. 
• 
Undetectable viral load: 
Proportion of HIV-positive participants with a viral load of <200 copies/mL at each follow-
up round, as reported in the Ministry of Public Health national database. 
• 
Current PrEP use: 
Proportion of HIV-negative participants who report currently using PrEP at each follow-
up round, based on self-reported data. 
4. Analysis Populations 
4.1 Intention-to-Treat (ITT) Population 
The ITT population will include all participants who completed the baseline assessment 
and were assigned to either the intervention or control site, regardless of their level of 

 
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participation in the intervention activities thereafter. This population will serve as the primary 
analytic population for evaluating the effectiveness of the intervention, reflecting real-world 
implementation outcomes. 
4.2 High Exposure Subgroup 
This subgroup will include participants from the intervention site who reported a high 
level of engagement with the BAAN HUG-M intervention activities at each follow-up round. This 
subgroup will be analyzed separately to evaluate the impact of sustained and intensive 
participation on health behaviors and outcomes. 
5. Data Management and Quality Assurance 
5.1 Handling of Missing Data 
Data collection will be conducted using an online survey platform (Qualtrics)4 with 
enforced “force response” and appropriately programmed skip logic to minimize item non-
response and ensure completeness of key variables. These design features significantly 
reduced the risk of missing data, especially at baseline. 
However, due to the longitudinal nature of the study and the possibility of participant 
drop-out or missed follow-up visits, some missing data may still occur, particularly in follow-up 
rounds. In such cases, missing values will be clearly identified and coded within the dataset. 
For statistical analysis, appropriate methods will be employed to handle missing data. 
When the proportion of missing data is non-trivial, we will compare the characteristics of 
participants with complete versus incomplete data. Depending on the nature and extent of 
missingness, we will use multiple imputation (MI) or maximum likelihood (ML) methods under 
the assumption that the data are missing at random (MAR).5 Sensitivity analyses using pattern-
mixture models will also be conducted to assess the robustness of the MAR assumption.6 
Complete case analysis may be applied in cases where missingness is minimal and ignorable. 
5.2 Data Cleaning and Preparation 
Following data export from the Qualtrics platform, the research team will perform 
systematic data cleaning procedures to ensure data quality, consistency, and readiness for 
analysis. This process will be conducted using STATA7 syntax and command scripts to 
automate checks and corrections. 
Key steps in data cleaning will include the detection of outliers and logically inconsistent 
responses, verification of skip logic compliance, and range checks for numeric variables. 
Variables that are expected to align conditionally (e.g., responses to dependent questions) will 
be cross validated for logical coherence. 
In preparation for analysis, data from three key sources will be merged and harmonized: 
• Self-administered questionnaires (Qualtrics) 
• Laboratory-based test results (chlamydia and gonorrhea from self-collected urine and 
anal specimens) 

 
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• HIV-related clinical data (e.g., HIV status, ART access, viral load) from the Ministry of 
Public Health national HIV database. 
To enable accurate data linkage across timepoints and data sources, participants will be 
assigned a Unique Identification Code (UIC), which comprises parts of the participant’s last 
name and date of birth. Additionally, linkage to the Ministry of Public Health national HIV 
database will use the participant’s 13-digit national ID number alongside the UIC to ensure 
robust data matching. The UIC will play a central role in aligning participant records across 
survey rounds, lab results, and national HIV data systems while preserving confidentiality. 
5.3 Variable Coding and Labeling 
All variables will be coded and labeled systematically following a standardized data 
dictionary. Coding will be consistent across all follow-up rounds. For example, dichotomous 
variables will be labeled as “1 = Yes” and “0 = No,” and Likert-scale items will include clearly 
defined scales. This consistency supports accurate interpretation, longitudinal comparison, and 
reproducibility of analyses in the future. 
6. Statistical Methods 
6.1 Descriptive Analysis 
Descriptive statistics will be used to summarize baseline characteristics and study 
variables, stratified by study arm (intervention vs. control). All statistical comparisons will be 
made between the two study sites — Ubon Ratchathani (intervention site) and Mahasarakham 
(control site) to assess the impact of the BAAN HUG-M intervention over time. Frequencies and 
percentages will be used for categorical variables and means with standard deviations or 
medians with interquartile ranges will be used for continuous variables, depending on their 
distribution. 
6.2 Primary and Secondary Outcome Analyses 
To evaluate the effects of the intervention over time, Generalized Estimating Equations 
(GEE) with appropriate link functions (e.g., logit for binary outcomes, identity for continuous 
outcomes) will be used.8 The models will include study arm (intervention vs. control), time 
(follow-up visits), and their interaction term to estimate intervention effects over time. Robust 
standard errors will be used to account for within-subject correlation. Person-time will be 
calculated and compared using rate ratios and 95% confidence intervals. 
6.3 Multiple Comparisons and p-value Adjustment 
If multiple statistical comparisons are conducted for secondary outcomes or subgroup 
analyses, adjustments for multiple testing will be considered using methods such as Bonferroni 
or false discovery rate (FDR) correction to control for type I error. 
6.4 Statistical Software 
All analyses will be conducted using STATA (version 18.0), which is the primary software 
tool used by the research team for data management, descriptive statistics, regression 
modeling, and longitudinal analyses. 

 
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7. Subgroup and Sensitivity Analyses 
7.1 Subgroup Analysis 
Subgroup analysis will be conducted to explore whether the effects of the intervention vary 
across specific participant characteristics. Pre-specified subgroups will include: 
• 
Age groups (15–19, 20–24, 25–29 years) 
• 
Level of exposure to the BAAN HUG-M intervention (high vs. low/moderate — 
intervention site only) 
• 
Province (Ubon Ratchathani vs. Mahasarakham) 
Interaction terms will be incorporated into the GEE models to evaluate whether intervention 
effects differ significantly across these subgroups. 
7.2 Sensitivity Analysis 
Sensitivity analyses will be performed to examine the robustness of the study findings under 
alternative assumptions. These may include: 
• 
Varying the model assumptions (e.g., using alternative link functions or comparing GEE 
models with mixed-effects models) 
8. References 
1. Scott HM, Pollack L, Rebchook GM, Huebner DM, Peterson J, Kegeles SM. Peer social 
support is associated with recent HIV testing among young black men who have sex with men. 
AIDS and Behavior. 2014 May 1;18(5):913-20. 
2. Gardner LI, Metsch LR, Anderson-Mahoney P, Loughlin AM, Del Rio C, Strathdee S, Sansom 
SL, Siegal HA, Greenberg AE, Holmberg SD. Efficacy of a brief case management intervention 
to link recently diagnosed HIV-infected persons to care. AIDS. 2005 Mar 4;19(4):423-31. 
3. Zablotska I, Grulich AE, Phanuphak N, Anand T, Janyam S, Poonkasetwattana M, Baggaley 
R, Griensven F, Lo YR. PrEP implementation in the Asia-Pacific region: opportunities, 
implementation and barriers. Journal of the International AIDS Society. 2016 Oct 1;19(7S6). 
4. Qualtrics. Qualtrics XM Platform™ [Survey Software]. Provo (UT): Qualtrics; 2024. Available 
from: https://www.qualtrics.com 
5. Little RJA, Rubin DB. Statistical Analysis with Missing Data. John Wiley & Sons; 2014. 
6. Hedeker D, Gibbons RD. Application of random-effects pattern-mixture models for missing 
data in longitudinal studies. Psychol Methods. 1997;2(1):64-78. doi:10.1037/1082-989X.2.1.64. 
7. StataCorp. Stata Statistical Software: Release 18. College Station (TX): StataCorp LLC; 
2023. 
8. Ito T, Sugasawa S. Grouped generalized estimating equations for longitudinal data analysis. 
Biometrics. 2023 Sep;79(3):1868–1879. doi:10.1111/biom.13718.