Page 156 - HIVMED_v21_i1.indb

Page 3 of 9 Original Research

follow-up, power was estimated to be > 80% to detect a 5% Participants received BWP100 (approximately USD$8 at
increase in the proportion of men who engage in high-risk study initiation) at each post-operative visit as compensation
sexual behaviour at 3 months post-circumcision (relative for their time and travel costs.
to baseline) based on a sample size of 523 participants.
Power was estimated to be 99% for a 10% increase at 3 months The current analysis is restricted to data collected at baseline
post-VMMC. and the 3-month follow-up visit when the sexual behaviour
questionnaire was repeated. Study data were collected and
Measures managed by using Research Electronic Data Capture
(REDCap), a secure, web-based application designed to
In addition to the primary endpoints, the baseline support data capture for research studies hosted at the
questionnaire also collected information on demographics Institute for Translational Health Sciences at the University
(age, current relationship status and religious affiliation), of Washington. 20
socioeconomic indicators (education, employment status,
electricity in household, refrigerator in household and use Outcomes
of wood as cooking fuel), frequency and intensity of alcohol
consumption, age at sexual initiation and history of The primary outcomes of the current analysis were (1) the
transactional sex. We also collected information on the number of sexual partners in the previous 1 month and (2) one
primary reason for getting circumcised (i.e. protecting against or more concurrent sexual partnerships during the previous
HIV, personal hygiene or other), whether the participant 3 months. In accordance with the Joint United Nations
believed circumcision would have a negative, positive or Programme on HIV/AIDS (UNAIDS) recommendations, we
no impact on the quality of sex, and administered a four- defined a concurrent sexual partnership as ‘overlapping
question scale developed in South Africa to assess attitudes sexual partnerships in which sexual intercourse with one
towards condom use, monogamy and HIV risk in the context partner occurs between two acts of intercourse with another
21
of circumcision. Lastly, we constructed two indicators partner’. Concurrency was then assessed by using the
19
evaluating the accuracy of participants’ knowledge regarding following three questions (based on UNAIDS recommendations
the effect of VMMC on female-to-male and male-to-female for data collection), each of which was asked of participant’s
HIV transmission. Specifically, we classified men as having three most recent sexual partners: ‘How long ago did you first
correct knowledge if they indicated that VMMC partially have sexual intercourse with this person?’ ‘When was the last
protects a man from getting HIV from a woman but does not time you had sexual intercourse with this person?’ and ‘Are
affect a woman’s chances of getting HIV from a man. you still having sex with this person?’

To evaluate the change in the number of sexual partners and
Data collection engagement in concurrent sexual partnerships before and
Before undergoing circumcision, all study participants were after undergoing VMMC, we constructed change scores for
asked to complete a baseline sexual behaviour questionnaire each endpoint, which subtracted participants’ baseline
through an audio computer-assisted self-interviewing response from that reported at the 3-month follow-up
(ACASI) tool in a private office room at the study site. This interview.
interviewing technique circumvented Social Desirability bias
by allowing the participant to complete the questionnaire in a Statistical analyses
standardised format without having to share their responses For the continuous outcome, the number of sexual partners
with study personnel directly. However, if the participant was (past 1 month), we fit an intercept-only inverse-probability
unable or preferred not to use the ACASI tool, the study nurse weighted linear regression model to estimate the mean
was available to administer the questionnaire. The tool, change in the number of partners at 3 months post-VMMC
available in both English and the local language, Setswana, (compared to baseline). For the dichotomous outcome,
was developed by using Questionnaire Development System engagement in concurrent sexual partnerships (past 3
(QDS ) questionnaire and survey development software months), we fit an inverse-probability weighted conditional
TM
adapted for low literacy and computer naïve populations logistic regression model (stratified on the participant)
(Nova Research Company, Silver Spring, MD). to estimate the change in the proportion of participants
reporting sexual concurrency at 3 months post-VMMC
After circumcision, post-procedure visits at 2 days, 7 days, (compared with baseline).
6 weeks and 3 months were scheduled as outlined by the
Botswana Ministry of Health (MOH) guidelines for adult Inverse probability weighting was used to adjust for potential
VMMC. At each visit, participants completed the follow-up selection bias because of non-trivial (anticipated to be 20%
survey through ACASI during their clinic appointment. before study start) loss to follow-up. 22,23,24 Inverse-probability
A follow-up visit at 12 months was planned to coincide weighting adjusts for loss to follow-up by empirically
with annual HIV testing as per standard of care in Botswana. breaking the association between observed predictors
Each study participant was provided with a wallet-size (collected at baseline) and participation at follow-up,
reminder card noting the date of each follow-up visit. allowing for unbiased estimation in the weighted sample,

http://www.sajhivmed.org.za 148 Open Access