Pre-exposure Prophylaxis Implementation in Central-Eastern European Countries

A continuous measure of blood plasma concentration of tenofovir diphosphate (TFVdp) from PrEP medication determined using via dried blood spot (DBS) analysis. A higher measure of fmol TFVdp demonstrates greater PrEP adherence (i.e., a better outcome).

A binary measure of PrEP adherence obtained from participant self-report data. Each week, participants mark the days over the past week on which they took or missed their PrEP dose. Each participant's weekly survey results are averaged to determine their mean number of PrEP doses taken per week over the past 3 months. The binary version of this outcome is defined as: 0-3 doses per week, on average, vs. ≥4 doses per week, on average, with ≥4 doses representing a sufficient level of PrEP adherence to be protected against HIV transmission (i.e., a better outcome).

A continuous measure of PrEP adherence obtained from participant self-report data. Each week, participants mark the days over the past week on which they took or missed their PrEP dose. Each participant's weekly survey results are averaged to determine their mean number of PrEP doses taken per week over the past 3 months, with higher numbers indicating greater PrEP adherence (i.e., a better outcome).

PrEP motivation is assessed through participants responses to a single question ("If you are using/were to use PrEP, how motivated are you/would you be to take the pill every day?") with responses scored from 1 to 7 (1=not at all motivated 7=extremely motivated). Higher scores indicate greater PrEP motivation (i.e., a better outcome).

PrEP knowledge is measured through 3 multiple choice questions about PrEP efficacy (e.g., "If taken as indicated by the provider, how effective is PrEP at preventing HIV infection?") where responses are scored as 0 (incorrect or unsure) or 1 (correct). Participants responding correctly to all 3 questions are assigned a total score of 1 (higher PrEP knowledge (i.e., a better outcome)), whereas all others are assigned a total score of 0.

Pro-PrEP attitudes and beliefs are measured via a 3-item scale scale consisting of statements describing favorable opinions about PrEP (e.g., "A daily pill would be a good way to protect myself against HIV"). Respondents mark their level of agreement with each item on a scale from 1 (totally disagree) to 5 (totally agree). The 3 individual item scores are summed to obtain an overall score from 5-15, where higher overall scores indicate greater positive attitudes/beliefs about PrEP (i.e., a better outcome).

Negative PrEP attitudes and beliefs are measured via a 7-item scale scale consisting of statements describing negative opinions about PrEP (e.g., " I would be very embarrassed to take HIV medication if I didn't have HIV"). Respondents mark their level of agreement with each item on a scale from 1 (totally disagree) to 5 (totally agree). The 7 individual item scores are summed to obtain an overall score from 7-35, where higher overall scores indicate greater negative attitudes/beliefs about PrEP (i.e., a worse outcome).

Barriers to taking PrEP are measured via an 11-item scale scale consisting of statements describing potential barriers to taking PrEP (e.g., "the fact that you have to take a pill every day"). Respondents mark the degree to which each item is important to them on a scale from 1 (not important at all) to 5 (extremely important). The 11 individual item scores are summed to obtain an overall score from 11-55, where higher overall scores indicate more barriers to taking PrEP (i.e., a worse outcome).

Facilitators for taking PrEP are measured via an 8-item scale scale consisting of statements describing potential facilitators for taking PrEP (e.g., "the fact that I don't have to pay for PrEP"). Respondents mark the degree to which each item is important to them on a scale from 1 (not important at all) to 5 (extremely important). The 8 individual item scores are summed to obtain an overall score from 8-40, where higher overall scores indicate more facilitators for taking PrEP (i.e., a better outcome).

The PrEP Stigma Scale-Shortened Version is an 11 item scale measuring anticipated and/or perceived stigma related to PrEP use. Participants state their level of agreement (1=strongly disagree, 5=strongly agree) to statements about PrEP-related stigma (e.g., "My friends would think less of me if they found out I was using PrEP"). Item scores are summed to obtain an overall score from 11 to 55, with higher total scores indicate increased stigma (i.e., a worse outcome).

The Patient Health Questionnaire-9 item (PHQ-9) measures severity of depression symptoms in the last 2 weeks, with respondents quantifying the frequency (0=not at all, 3=nearly every day) of their depression symptoms (e.g., Little interest or pleasure in doing things). Item scores are summed to obtain an overall score from 0-27 with higher overall scores indicate increased depression symptoms (i.e., a worse outcome).

The Generalized Anxiety Disorder 7-item(GAD-7) measures severity of anxiety symptoms in the last 2 weeks, with respondents quantifying the frequency (0=not at all, 3=nearly every day) of their anxiety symptoms (e.g., Feeling nervous, anxious or on edge). Item scores are summed to obtain an overall score from 0-21 with higher overall scores indicate increased anxiety symptoms (i.e., a worse outcome).

HIV risk, measured by number of condomless anal sex (CAS) acts with an HIV-positive or status-unknown male partner over the past 6 months is self-reported by participants. A higher number of CAS acts represents greater HIV risk (i.e., a worse outcome).

Participants were asked whether they had been diagnosed with any bacterial sexually transmitted infections (STIs) over the past 6 months. This self-reported measure was coded in a binary manner as either yes (i.e., a worse outcome) or no.