Epidemiology
ORIGINAL ARTICLE
STI/HIV test result disclosure between female sex workers and their primary, non-commercial male partners in two Mexico-US border cities: a prospective study Heather A Pines,1 Thomas L Patterson,2 Gudelia Rangel,3 Gustavo Martinez,4 Angela R Bazzi,5 Monica D Ulibarri,2 Jennifer L Syvertsen,6 Natasha K Martin,7,8 Steffanie A Strathdee1 For numbered affiliations see end of article. Correspondence to Dr Heather A Pines, Division of Global Public Health, Department of Medicine, University of California, San Diego, 9500 Gilman Dr., MC 0507, La Jolla, CA 92093-0507, USA; [email protected] Received 14 May 2014 Revised 28 August 2014 Accepted 21 September 2014 Published Online First 8 October 2014
ABSTRACT Objectives Disclosure of sexually transmitted infections (STI)/HIV diagnoses to sexual partners is not mandated by public health guidelines in Mexico. To assess the feasibility of couples-based STI/HIV testing with facilitated disclosure as a risk-reduction strategy within female sex workers’ (FSW) primary partnerships, we examined STI/HIV test result disclosure patterns between FSWs and their primary, non-commercial male partners in two Mexico–US border cities. Methods From 2010 to 2013, 335 participants (181 FSWs and 154 primary male partners) were followed for 24 months. At semiannual visits, participants were tested for STIs/HIV and reported on their disclosure of test results from the previous visit. Multilevel logistic regression was used to identify individual-level and partnership-level predictors of cumulative (1) nondisclosure of ≥1 STI test result and (2) non-disclosure of ≥1 HIV test result within couples during follow-up. Results Eighty-seven percent of participants reported disclosing all STI/HIV test results to their primary partners. Non-disclosure of ≥1 STI test result was more common among participants who reported an STI diagnosis as part of the study (adjusted OR=3.05, 95% CI 1.13 to 8.25), while non-disclosure of ≥1 HIV test result was more common among participants in longerduration partnerships (AOR=1.15 per year, 95% CI 1.03 to 1.28). Drug use before/during sex within partnerships was associated with non-disclosure of both STI (AOR=5.06, 95% CI 1.64 to 15.62) and HIV (AOR=4.51, 95% CI: 1.32 to 15.39) test results. Conclusions STI/HIV test result disclosure was highly prevalent within FSWs’ primary partnerships, suggesting couples-based STI/HIV testing with facilitated disclosure may be feasible for these and potentially other high-risk, socially marginalised couples.
INTRODUCTION
To cite: Pines HA, Patterson TL, Rangel G, et al. Sex Transm Infect 2015;91:207–213.
Globally, female sex workers (FSW) are disproportionately affected by sexually transmitted infections (STI), including HIV.1 Although FSWs’ elevated risk of STI/HIV acquisition has been attributed to various individual, interpersonal and structural factors, research documenting lower rates of condom use during sex with primary, noncommercial male partners than with clients2 3 has underscored FSWs’ need for couples-based
STI/HIV prevention interventions.4 Couples HIV counselling and testing (CHCT) is an intervention promoted by the US Centers for Disease Control and Prevention that involves risk assessment, pre-test and post-test counselling, the development of personalised risk reduction plans and facilitated test result disclosure.5 The efficacy of CHCT in reducing STI/HIV-related risk behaviours has been demonstrated among heterosexual couples in Africa and the Caribbean,6 as well as partnerships between substance-using women and their primary male partners in the US.7 However, couples-based STI/HIV counselling and testing interventions with facilitated test result disclosure have not been evaluated within FSWs’ primary partnerships in resource-constrained settings. Mexico’s nation-wide HIV prevalence is 0.3%; however, a dynamic subepidemic has emerged among FSWs along the Mexico–US border.8 In Tijuana and Ciudad Juárez, the largest Mexico–US border cities, sex work is concentrated in zona rojas (red light districts) where it is legally tolerated.8 The Tijuana zona roja is situated in a neighbourhood adjacent to the US border, while sex work is more dispersed throughout the downtown area in Ciudad Juárez. In both cities, FSWs work in bars/nightclubs, cantinas, motels and on the street.8 In a 2006 study conducted among FSWs in the Mexico–US border region, prevalence of HIV, gonorrhoea, chlamydia and active syphilis (titres ≥1:8) were 6%, 6%, 13% and 14%, respectively,9 while HIV prevalence among FSWs who inject drugs was 12%.10 In Tijuana, 30%–50% of FSWs have primary, non-commercial male partners with whom condom use is rare.11 12 To investigate the potential contribution of FSWs’ primary, non-commercial male partners to this growing subepidemic among FSWs, Proyecto Parejas (Couples Project) was conducted between 2010 and 2013 to examine the context and epidemiology of STIs/HIV among FSWs and their primary, non-commercial male partners in Tijuana and Ciudad Juárez.13 To date, Proyecto Parejas findings suggest that STI/ HIV prevalence may be lower among FSWs with primary, non-commercial male partners (HIV=3.8%, gonorrhoea=0.9%, chlamydia=7.5% and active syphilis=1.4%) than previously reported for FSWs overall, and even lower among their primary male
Pines HA, et al. Sex Transm Infect 2015;91:207–213. doi:10.1136/sextrans-2014-051663
207
Epidemiology
As previously described,13 FSWs were recruited via targeted sampling in areas where sex work visibly occurs (e.g., bars, motels and street corners) and snowball sampling (i.e., enrolled FSWs referred other women they believed to be involved in sex work). Eligible women were asked to return to the study site with their primary, non-commercial male partners for a rigorous screening process to verify their status as a couple prior to enrolment. Eligible FSWs had to be ≥18 years of age; report ever using heroin, cocaine, crack or methamphetamine (due to the elevated rate of HIV previously observed among substance-using FSWs); report being in a partnership with a primary (i.e., someone with whom she lives or spends a considerable amount of time), non-commercial (i.e., someone with whom she does not exchange sex for money, drugs or other goods) male partner for ≥6 months; and report sex with their primary, noncommercial male partner as well as ≥1 client in the past month. FSWs were ineligible if they planned to imminently end their partnership, anticipated moving to another city, refused treatment for STIs or feared that participation would result in lifethreatening intimate partner violence (IPV). Eligible men had to be ≥18 years of age and report sex with their primary, FSW partner in the past month. While not required for enrolment, all men knew their primary partners engaged in sex work. Participants provided written informed consent and institutional review boards at the University of California, San Diego, Tijuana’s Hospital General, El Colegio de la Frontera Norte, and the Universidad Autónoma de Ciudad Juárez, approved all study protocols.
each visit, participants received pre-test and post-test counselling and underwent HIV, syphilis, chlamydia and gonorrhoea testing. Positive Advance Quality HIV rapid tests (InTech Products) were confirmed via western blot. Syphilis infection was identified via rapid plasma reagin (RPR) testing (Macro Vue, Becton Dickenson; Cockeysville, Maryland, USA) and the Treponema pallidum particle agglutination (TPPA) assay (Fujirebo; Wilmington, Delaware, USA). Active syphilis cases had positive RPR and TPPA test results and antibody titres ≥1:8. Urine samples were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using transcription-mediated amplification assays (Genprobe; San Diego, California, USA). Participants received rapid test results at each visit. The San Diego County Health Department conducted all chlamydia and gonorrhoea testing and confirmatory testing of rapid positive HIV and syphilis blood samples. Within 1 month, participants received confirmatory HIV and syphilis and all chlamydia and gonorrhoea test results. At that time, participants were encouraged to disclose their results to their primary partners. STI-positive participants were offered free treatment according to Mexican and US guidelines and HIV-infected participants were referred to municipal clinics for free care and treatment. Participants also completed interviewer-administered computer questionnaires at each visit, which collected information on sociodemographics, substance use, sexual behaviours, sexual and physical abuse, and primary partnership characteristics, including: partnership duration, partnership trust, partnership satisfaction, receipt of financial support from partners, conflict within partnerships, needle/syringe sharing within partnerships (past 6 months), substance use before/during sex within partnerships ( past 6 months) and sexual behaviours within partnerships (past month). Partnership trust was measured using a 10-point scale (1=‘I do not trust my partner at all’ to 10=‘I trust my partner with my life’).18 The sum of Likert scale responses (1=strongly disagree to 4=strongly agree) to 5 items of the Satisfaction with Married Life scale,19 such as ‘In most ways, my relationship with my partner is close to ideal’ (Cronbach’s α: FSWs=0.92; men=0.87), defined partnership satisfaction. Conflict ( psychological aggression, physical assault, injury and sexual coercion) victimisation and perpetration within partnerships was measured using 8 items of the Revised Conflict Tactic scale—Short Form (CTS2S).20 For each item, participants were asked if they had ever been the victim/perpetrator of a given behaviour within their partnership. For example: ‘My partner pushed, shoved, or slapped me’ (i.e., victimisation; Cronbachs’ α: FSWs=0.89; men=0.76) and ‘I pushed, shoved, or slapped my partner’ (i.e., perpetration; Cronbach’s α: FSWs=0.86; men=0.76). Binary variables for conflict victimisation and perpetration were created based on responses to the CTS2S. Beginning at visit 3, questionnaires collected information on participants’ STI/HIV test results from the previous visit: what their results were and whether they disclosed their results to their primary partners. Based on their disclosure history during the study period, regardless of whether results were positive or negative, two variables were created: (1) cumulative nondisclosure of ≥1 STI test result and (2) cumulative nondisclosure of ≥1 HIV test result. These binary variables (0=disclosed all STI/HIV test results vs. did not disclose ≥1 STI/HIV test result) were used as the outcomes in our analyses.
Study procedures
Sample selection and follow-up
Participants completed study visits every 6 months for 24 months (5 visits total) and were compensated US$20 for each visit. All study procedures were conducted individually. At
Of the 428 Proyecto Parejas participants, 370 completed ≥1 visit during which data on disclosure of test results from the prior visit were ascertained (visit 3, 4 or 5). Among those
partners (HIV=1.4%, gonorrhoea=1.4%, chlamydia=4.3% and active syphilis=1.4%).14 However, elevated rates of STI/ HIV-related risk behaviours were observed within this cohort.14 For example, at baseline, 64% of FSWs reported always having unprotected sex with their primary male partners (past month).15 Yet 16% of FSWs and their primary male partners reported concurrent partners with whom inconsistent condom use was common,15 and >50% of primary male partners reported injection drug use, which was associated with ever having sex with other men and exchanging money or goods for sex.16 Moreover, these couples expressed difficulty disclosing extra-dyadic risk behaviours, which may exacerbate their risk.17 Disclosure of STI/HIV diagnoses to sexual partners is not mandated by public health guidelines in Mexico (Dr. Carlos Magis-Rodriguez, personal communication, 2014). Thus, little is known about current patterns of STI/HIV test result disclosure between FSWs and their primary, non-commercial male partners and whether couples-based STI/HIV counselling and testing with facilitated disclosure would be a feasible risk-reduction strategy for this population. To inform the development of such interventions, we investigated the prevalence and correlates of STI/HIV test result disclosure between FSWs and their primary, non-commercial male partners participating in Proyecto Parejas. We hypothesised that non-disclosure would be associated with both individual-level (e.g., being STI/HIV positive and having concurrent partners) and partnership-level (e.g., partnership duration and drug use before/during sex) characteristics.
METHODS Study population
208
Pines HA, et al. Sex Transm Infect 2015;91:207–213. doi:10.1136/sextrans-2014-051663
Epidemiology participants, 335 (181 FSWs and 154 male partners) provided data that could be used to determine their cumulative STI/HIV test result disclosure status, and were included in our sample. Our sample contains an unequal number of FSWs and male partners because one member of the couple was lost to follow-up or did not provide disclosure data (FSWs=8 and men=21) or the partnership dissolved during follow-up (men=14) (follow-up of men was discontinued in the event of partnership dissolution). Compared to those with complete follow-up, those who were lost to follow-up, did not provide disclosure data, or whose partnerships dissolved did not differ significantly with respect to STI/HIV diagnoses during the study period. The 335 participants represented 189 primary partnerships overall: 146 in which both partners reported on disclosure, 35 in which only FSWs reported on disclosure and 8 in which only male partners reported on disclosure. In the analysis, participants were followed to their last study visit, partnership dissolution or the end of the study period, whichever came first.
Statistical analysis We calculated the Pearson-type pairwise interclass correlation coefficient (PICC) to determine the degree of within-dyad interdependence in cumulative STI/HIV test result disclosure.21 Given the potential for Type II errors, we used an α level of 0.20 to interpret the PICC and justify the use of a multilevel modelling approach for dyadic data.21 We used multilevel logistic regression to examine the effect of individual-level and partnership-level characteristics on (1) cumulative non-disclosure of ≥1 STI test result and (2) cumulative non-disclosure of ≥1 HIV test result. Characteristics significant at an α level of 0.10 in bivariate models were assessed for collinearity and included in multivariate models. If nondisclosure of ≥1 STI/HIV test result was reported by
ORIGINAL ARTICLE
STI/HIV test result disclosure between female sex workers and their primary, non-commercial male partners in two Mexico-US border cities: a prospective study Heather A Pines,1 Thomas L Patterson,2 Gudelia Rangel,3 Gustavo Martinez,4 Angela R Bazzi,5 Monica D Ulibarri,2 Jennifer L Syvertsen,6 Natasha K Martin,7,8 Steffanie A Strathdee1 For numbered affiliations see end of article. Correspondence to Dr Heather A Pines, Division of Global Public Health, Department of Medicine, University of California, San Diego, 9500 Gilman Dr., MC 0507, La Jolla, CA 92093-0507, USA; [email protected] Received 14 May 2014 Revised 28 August 2014 Accepted 21 September 2014 Published Online First 8 October 2014
ABSTRACT Objectives Disclosure of sexually transmitted infections (STI)/HIV diagnoses to sexual partners is not mandated by public health guidelines in Mexico. To assess the feasibility of couples-based STI/HIV testing with facilitated disclosure as a risk-reduction strategy within female sex workers’ (FSW) primary partnerships, we examined STI/HIV test result disclosure patterns between FSWs and their primary, non-commercial male partners in two Mexico–US border cities. Methods From 2010 to 2013, 335 participants (181 FSWs and 154 primary male partners) were followed for 24 months. At semiannual visits, participants were tested for STIs/HIV and reported on their disclosure of test results from the previous visit. Multilevel logistic regression was used to identify individual-level and partnership-level predictors of cumulative (1) nondisclosure of ≥1 STI test result and (2) non-disclosure of ≥1 HIV test result within couples during follow-up. Results Eighty-seven percent of participants reported disclosing all STI/HIV test results to their primary partners. Non-disclosure of ≥1 STI test result was more common among participants who reported an STI diagnosis as part of the study (adjusted OR=3.05, 95% CI 1.13 to 8.25), while non-disclosure of ≥1 HIV test result was more common among participants in longerduration partnerships (AOR=1.15 per year, 95% CI 1.03 to 1.28). Drug use before/during sex within partnerships was associated with non-disclosure of both STI (AOR=5.06, 95% CI 1.64 to 15.62) and HIV (AOR=4.51, 95% CI: 1.32 to 15.39) test results. Conclusions STI/HIV test result disclosure was highly prevalent within FSWs’ primary partnerships, suggesting couples-based STI/HIV testing with facilitated disclosure may be feasible for these and potentially other high-risk, socially marginalised couples.
INTRODUCTION
To cite: Pines HA, Patterson TL, Rangel G, et al. Sex Transm Infect 2015;91:207–213.
Globally, female sex workers (FSW) are disproportionately affected by sexually transmitted infections (STI), including HIV.1 Although FSWs’ elevated risk of STI/HIV acquisition has been attributed to various individual, interpersonal and structural factors, research documenting lower rates of condom use during sex with primary, noncommercial male partners than with clients2 3 has underscored FSWs’ need for couples-based
STI/HIV prevention interventions.4 Couples HIV counselling and testing (CHCT) is an intervention promoted by the US Centers for Disease Control and Prevention that involves risk assessment, pre-test and post-test counselling, the development of personalised risk reduction plans and facilitated test result disclosure.5 The efficacy of CHCT in reducing STI/HIV-related risk behaviours has been demonstrated among heterosexual couples in Africa and the Caribbean,6 as well as partnerships between substance-using women and their primary male partners in the US.7 However, couples-based STI/HIV counselling and testing interventions with facilitated test result disclosure have not been evaluated within FSWs’ primary partnerships in resource-constrained settings. Mexico’s nation-wide HIV prevalence is 0.3%; however, a dynamic subepidemic has emerged among FSWs along the Mexico–US border.8 In Tijuana and Ciudad Juárez, the largest Mexico–US border cities, sex work is concentrated in zona rojas (red light districts) where it is legally tolerated.8 The Tijuana zona roja is situated in a neighbourhood adjacent to the US border, while sex work is more dispersed throughout the downtown area in Ciudad Juárez. In both cities, FSWs work in bars/nightclubs, cantinas, motels and on the street.8 In a 2006 study conducted among FSWs in the Mexico–US border region, prevalence of HIV, gonorrhoea, chlamydia and active syphilis (titres ≥1:8) were 6%, 6%, 13% and 14%, respectively,9 while HIV prevalence among FSWs who inject drugs was 12%.10 In Tijuana, 30%–50% of FSWs have primary, non-commercial male partners with whom condom use is rare.11 12 To investigate the potential contribution of FSWs’ primary, non-commercial male partners to this growing subepidemic among FSWs, Proyecto Parejas (Couples Project) was conducted between 2010 and 2013 to examine the context and epidemiology of STIs/HIV among FSWs and their primary, non-commercial male partners in Tijuana and Ciudad Juárez.13 To date, Proyecto Parejas findings suggest that STI/ HIV prevalence may be lower among FSWs with primary, non-commercial male partners (HIV=3.8%, gonorrhoea=0.9%, chlamydia=7.5% and active syphilis=1.4%) than previously reported for FSWs overall, and even lower among their primary male
Pines HA, et al. Sex Transm Infect 2015;91:207–213. doi:10.1136/sextrans-2014-051663
207
Epidemiology
As previously described,13 FSWs were recruited via targeted sampling in areas where sex work visibly occurs (e.g., bars, motels and street corners) and snowball sampling (i.e., enrolled FSWs referred other women they believed to be involved in sex work). Eligible women were asked to return to the study site with their primary, non-commercial male partners for a rigorous screening process to verify their status as a couple prior to enrolment. Eligible FSWs had to be ≥18 years of age; report ever using heroin, cocaine, crack or methamphetamine (due to the elevated rate of HIV previously observed among substance-using FSWs); report being in a partnership with a primary (i.e., someone with whom she lives or spends a considerable amount of time), non-commercial (i.e., someone with whom she does not exchange sex for money, drugs or other goods) male partner for ≥6 months; and report sex with their primary, noncommercial male partner as well as ≥1 client in the past month. FSWs were ineligible if they planned to imminently end their partnership, anticipated moving to another city, refused treatment for STIs or feared that participation would result in lifethreatening intimate partner violence (IPV). Eligible men had to be ≥18 years of age and report sex with their primary, FSW partner in the past month. While not required for enrolment, all men knew their primary partners engaged in sex work. Participants provided written informed consent and institutional review boards at the University of California, San Diego, Tijuana’s Hospital General, El Colegio de la Frontera Norte, and the Universidad Autónoma de Ciudad Juárez, approved all study protocols.
each visit, participants received pre-test and post-test counselling and underwent HIV, syphilis, chlamydia and gonorrhoea testing. Positive Advance Quality HIV rapid tests (InTech Products) were confirmed via western blot. Syphilis infection was identified via rapid plasma reagin (RPR) testing (Macro Vue, Becton Dickenson; Cockeysville, Maryland, USA) and the Treponema pallidum particle agglutination (TPPA) assay (Fujirebo; Wilmington, Delaware, USA). Active syphilis cases had positive RPR and TPPA test results and antibody titres ≥1:8. Urine samples were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using transcription-mediated amplification assays (Genprobe; San Diego, California, USA). Participants received rapid test results at each visit. The San Diego County Health Department conducted all chlamydia and gonorrhoea testing and confirmatory testing of rapid positive HIV and syphilis blood samples. Within 1 month, participants received confirmatory HIV and syphilis and all chlamydia and gonorrhoea test results. At that time, participants were encouraged to disclose their results to their primary partners. STI-positive participants were offered free treatment according to Mexican and US guidelines and HIV-infected participants were referred to municipal clinics for free care and treatment. Participants also completed interviewer-administered computer questionnaires at each visit, which collected information on sociodemographics, substance use, sexual behaviours, sexual and physical abuse, and primary partnership characteristics, including: partnership duration, partnership trust, partnership satisfaction, receipt of financial support from partners, conflict within partnerships, needle/syringe sharing within partnerships (past 6 months), substance use before/during sex within partnerships ( past 6 months) and sexual behaviours within partnerships (past month). Partnership trust was measured using a 10-point scale (1=‘I do not trust my partner at all’ to 10=‘I trust my partner with my life’).18 The sum of Likert scale responses (1=strongly disagree to 4=strongly agree) to 5 items of the Satisfaction with Married Life scale,19 such as ‘In most ways, my relationship with my partner is close to ideal’ (Cronbach’s α: FSWs=0.92; men=0.87), defined partnership satisfaction. Conflict ( psychological aggression, physical assault, injury and sexual coercion) victimisation and perpetration within partnerships was measured using 8 items of the Revised Conflict Tactic scale—Short Form (CTS2S).20 For each item, participants were asked if they had ever been the victim/perpetrator of a given behaviour within their partnership. For example: ‘My partner pushed, shoved, or slapped me’ (i.e., victimisation; Cronbachs’ α: FSWs=0.89; men=0.76) and ‘I pushed, shoved, or slapped my partner’ (i.e., perpetration; Cronbach’s α: FSWs=0.86; men=0.76). Binary variables for conflict victimisation and perpetration were created based on responses to the CTS2S. Beginning at visit 3, questionnaires collected information on participants’ STI/HIV test results from the previous visit: what their results were and whether they disclosed their results to their primary partners. Based on their disclosure history during the study period, regardless of whether results were positive or negative, two variables were created: (1) cumulative nondisclosure of ≥1 STI test result and (2) cumulative nondisclosure of ≥1 HIV test result. These binary variables (0=disclosed all STI/HIV test results vs. did not disclose ≥1 STI/HIV test result) were used as the outcomes in our analyses.
Study procedures
Sample selection and follow-up
Participants completed study visits every 6 months for 24 months (5 visits total) and were compensated US$20 for each visit. All study procedures were conducted individually. At
Of the 428 Proyecto Parejas participants, 370 completed ≥1 visit during which data on disclosure of test results from the prior visit were ascertained (visit 3, 4 or 5). Among those
partners (HIV=1.4%, gonorrhoea=1.4%, chlamydia=4.3% and active syphilis=1.4%).14 However, elevated rates of STI/ HIV-related risk behaviours were observed within this cohort.14 For example, at baseline, 64% of FSWs reported always having unprotected sex with their primary male partners (past month).15 Yet 16% of FSWs and their primary male partners reported concurrent partners with whom inconsistent condom use was common,15 and >50% of primary male partners reported injection drug use, which was associated with ever having sex with other men and exchanging money or goods for sex.16 Moreover, these couples expressed difficulty disclosing extra-dyadic risk behaviours, which may exacerbate their risk.17 Disclosure of STI/HIV diagnoses to sexual partners is not mandated by public health guidelines in Mexico (Dr. Carlos Magis-Rodriguez, personal communication, 2014). Thus, little is known about current patterns of STI/HIV test result disclosure between FSWs and their primary, non-commercial male partners and whether couples-based STI/HIV counselling and testing with facilitated disclosure would be a feasible risk-reduction strategy for this population. To inform the development of such interventions, we investigated the prevalence and correlates of STI/HIV test result disclosure between FSWs and their primary, non-commercial male partners participating in Proyecto Parejas. We hypothesised that non-disclosure would be associated with both individual-level (e.g., being STI/HIV positive and having concurrent partners) and partnership-level (e.g., partnership duration and drug use before/during sex) characteristics.
METHODS Study population
208
Pines HA, et al. Sex Transm Infect 2015;91:207–213. doi:10.1136/sextrans-2014-051663
Epidemiology participants, 335 (181 FSWs and 154 male partners) provided data that could be used to determine their cumulative STI/HIV test result disclosure status, and were included in our sample. Our sample contains an unequal number of FSWs and male partners because one member of the couple was lost to follow-up or did not provide disclosure data (FSWs=8 and men=21) or the partnership dissolved during follow-up (men=14) (follow-up of men was discontinued in the event of partnership dissolution). Compared to those with complete follow-up, those who were lost to follow-up, did not provide disclosure data, or whose partnerships dissolved did not differ significantly with respect to STI/HIV diagnoses during the study period. The 335 participants represented 189 primary partnerships overall: 146 in which both partners reported on disclosure, 35 in which only FSWs reported on disclosure and 8 in which only male partners reported on disclosure. In the analysis, participants were followed to their last study visit, partnership dissolution or the end of the study period, whichever came first.
Statistical analysis We calculated the Pearson-type pairwise interclass correlation coefficient (PICC) to determine the degree of within-dyad interdependence in cumulative STI/HIV test result disclosure.21 Given the potential for Type II errors, we used an α level of 0.20 to interpret the PICC and justify the use of a multilevel modelling approach for dyadic data.21 We used multilevel logistic regression to examine the effect of individual-level and partnership-level characteristics on (1) cumulative non-disclosure of ≥1 STI test result and (2) cumulative non-disclosure of ≥1 HIV test result. Characteristics significant at an α level of 0.10 in bivariate models were assessed for collinearity and included in multivariate models. If nondisclosure of ≥1 STI/HIV test result was reported by
