Design and Development of a Mobile App to Improve Adherence to Pre-exposure Prophylaxis in Men Who Have Sex With Men: A Pilot Study
Phase: NA
Conditions: HIV Infections, Pre-Exposure Prophylaxis
Sponsor: National Cheng Kung University

 

Study design: This study is an open label, single group assignment, interventional 
study, aiming to examine the preliminary effectiveness of the app in monitoring 
adherence to PrEP. The study expects to enroll participants since May, 2020 and 
follow-up for 4 months.  
Participants: 
Inclusion criteria: 
 Male. 
 Aged 20 or above. 
 Resides in Taiwan and able to understand, read, and speak Mandarin Chinese. 
 Remains HIV negative prior to and during the study period. 
 The results of the laboratory tests are eligible to initiate PrEP. 
 Currently taking PrEP or willing to initiate PrEP. 
 Reports having 4 times or above anal sex with men in the past month. 
 Owns an Android or Apple operating system (iOS) smartphone and willing to 
download the study app. 
 Willing to wear the device we provided during the study period. 
Exclusion criteria: 
 With abnormal kidney function (creatinine clearance rate ≦ 60 mL/minute). 
 Currently on medication that might interact with PrEP, such as drugs contain 
lamivudine in the pre-PrEP assessment. 
 
Sample size: above 30 participants and 70 participants at maximum. The sample size 
calculation is based on central limit theorem (CLT), which states that the distribution 
of sample means approximates a normal distribution as the sample size gets larger. 
CLT refers to that sample sizes equal to or greater than 30 are considered sufficient 
for the CLT to hold.  
Interventions: The UPrEPU app is a self-monitoring tool to improve PrEP adherence 
regardless of the MSM user’s choice of dosing regimen and lifestyle. All of 
participants will receive access to all the app capabilities. The app features include 
information on HIV testing locations, sex and PrEP diary and reminder of taking 
PrEP. 
Data Collection:  
Recruitment: Participants from two medical centers in two major cities of Taiwan. 
Potential study participants will be referred by physicians and case navigators from 
the clinics.  
Screening: Their eligibility will be assessed by a screening tool available online. 
Screening questionnaire shown in Table 1. The participants’ answers have to meet 
“Answers to enroll” in each question to enroll this study.  

 
Table 1. Screening questionnaire   
Questions 
Options 
Answers to enroll 
What is your gender 
□ Male □Female 
Male 
Are you able to 
understand, read, and 
speak Mandarin Chinese 
□ Yes □ No 
Yes 
Are you living in Taiwan 
□ Yes □ No 
Yes 
HIV status  
□ Positive □ Negative 
Negative 
Do you assess the pre-
PrEP assessment and 
eligible to use PrEP  
□ Yes □ No 
Yes 
Birth Year 
Open question 
<=1999 
Currently or willing to use 
PrEP 
□ Yes □ No 
Yes 
Do you ever have anal 
intercourse with men 
□ Yes □ No 
Yes 
How many episodes of 
anal intercourse with men 
in the past month 
Open question 
>=4 
What is your cell phone 
brands and models 
Open question 
Only smart phone is 
available  
Afterward, trained research assistants will inform those who are eligible about the 
purposes of the study and the information that will be collected in the study. 
Individuals who express interest in this study will be required to provide signed 
informed consent. For those who do not consent to participate, the reasons for 
declining participation will be documented.  
Baseline visit: Eligible participants will download the UPrEPU app on their phone 
and answer a baseline questionnaire in the app regarding sociodemographics, mental 
health scales, sexual behaviors, and PrEP use at the baseline visit at the study site. 
Participants will also receive a wearable device that collects physiological sensor data. 
Participants will be encouraged to use all app components over the next four months 
and wear the wearable devices at all times. 
Follow-up visit: Participants will be followed up monthly for the four months at the 
two medical centers where they were recruited. Each monthly visit will include rapid 
testing for HIV antigen and antibodies, measuring TDF/FTC concentration, and 
complete a follow-up questionnaire on their mental health scales, sexual behaviors, 
and PrEP use. Depression and anxiety will be assessed by Patient Health 

Questionnaire-9 (PHQ-9) and General Anxiety Disorder-7 (GAD-7). We collect these 
two mental health indicators since studies have shown that mental health status may 
be associated with adherence to medications. 
Kidney function and sexually transmitted infections will be assessed at the end of 
follow-up. The system usability scale (SUS) for the UPrEPU app will be assessed 
during the first follow-up visit and at the end of the study. A face-to-face, semi-
structured qualitative interview will be conducted at each visit to assess the feasibility 
of the app. It will focus on any technical challenges participants may have 
encountered, recommendations for app improvement, and their satisfaction and 
comfort in using this app. All interviews will take around 30 minutes and will be 
audio-recorded for transcription and analysis. Data collection Items and Schedule 
shown in Table 2. 
Table 2. Data collection Items and Schedule 
 
Screening 
Baseline 
F-up -1 
F-up -2 
F-up -3 
F-up -4 
1. 
Eligibility/Interest 
● 
 
 
 
 
 
2. 
Informed Consent 
● 
 
 
 
 
 
3. 
Blood sample 
 
● 
● 
● 
● 
● 
A. Drug 
concertation  
◎Can be 
collected either 
F-up-2, F-up-3, 
or F-up-4 
 
 
 
◎ 
◎ 
◎ 
B. HIV test  
 
● 
● 
● 
● 
● 
C. Liver and kidney 
function 
 
● 
 
 
 
● 
D. Syphilis 
screening 
 
● 
 
 
 
● 
4. 
Installing UPrEPU 
app 
 
● 
 
 
 
 
5. 
Set up smart device 
 
● 
 
 
 
 
6. 
Receive data in smart 
device 
 
 
● 
● 
● 
● 
7. 
Baseline 
questionnaire  
 
● 
 
 
 
 

8. 
Follow-up 
questionnaire 
 
 
● 
● 
● 
● 
9. 
SUS questionnaire  
 
 
● 
 
 
 
10. 
APP feasibility 
interview  
 
 
● 
● 
● 
● 
11. 
Incentive  
 
 
$20 
$20 
$20 
$20 
OR $53 
Incentives: Participants will receive incentives for completing each follow-up visit 
and in-depth interview. This includes US $20 cash for each follow-up visit and US 
$33 cash for twice completing the in-depth interviews. Participants whose cumulative 
frequency of log-in and use of features reached 90% will receive an additional US $33 
at the end of the study. 
Statistical analysis plan: Usability of the app will be measured by the System 
Usability Scale (SUS), a 10-item, 5-point Likert scale, which gives a global view of 
subjective assessment of usability [1]. A score above 50 out of 100 indicates 
acceptable [2].The primary feasibility outcomes include frequency of app log-in, use 
of app components such as PrEP-taking and sexual behavior reports, and the length of 
time of the app use based on the app analytics. Descriptive statistics will be used and 
confidence intervals will be calculated to evaluate the primary feasibility outcomes. 
Secondary feasibility outcomes of this app will be analyzing data from qualitative 
interviews focusing on technical challenges and satisfaction of the app during the 
follow-up with thematic analysis methods.  
We will examine the app users’ effectiveness of adherence monitoring for this app by 
comparing the pill-taking reports in the PrEP-taking diary component in the app with 
the Tenofovir (TDF) and Emtricitabine (FTC) drug concentration in dried blood spot 
(DBS) samples in the previous seven days before the follow-up day. We will use 
correlation analysis to examine the consistency between the drug concentration in the 
DBS samples and self-reported PrEP diary in the app. Higher correlation reflects 
higher effectiveness of adherence monitoring. 
 
 

Reference 
1. 
Brooke J, SUS-A quick and dirty usability scale. Usability evaluation in 
industry. Vol. 189. 1996. 4-7. 
2. 
Bangor A, Kortum PT, and Miller JT, An empirical evaluation of the system 
usability scale. Intl. Journal of Human–Computer Interaction, 2008. 24(6): 
574-594.