Incident Trichomonas vaginalis Is Associated With Partnership Concurrency: A Longitudinal Cohort Study

Disparities in adherence to retesting guidelines in women with Trichomonas vaginalis infection

BACKGROUND

Trichomoniasis is the most prevalent nonviral sexually transmitted infection in the United States. Numerous studies have shown disproportionately higher prevalence rates in non-Hispanic Black women. Because of the high rates of reinfection, the Centers for Disease Control and Prevention recommends retesting women treated for trichomoniasis. Despite these national guidelines, there are few studies examining adherence to retesting recommendations for patients with trichomoniasis. Adherence to retesting guidelines has been shown in other infections to be an important determinant of racial disparities.

OBJECTIVE

This study aimed to describe Trichomonas vaginalis infection rates, evaluate adherence to retesting guidelines, and examine characteristics of women who were not retested according to the guidelines in an urban, diverse, hospital-based obstetrics and gynecology clinic population.

STUDY DESIGN

We conducted a retrospective cohort study of patients from a single hospital-based obstetrics and gynecology clinic who were tested for Trichomonas vaginalis between January 1, 2015 and December 31, 2019. Descriptive statistics were used to examine guideline-concordant testing for reinfection among patients with trichomoniasis. Multivariable logistic regression was used to identify characteristics associated with testing positive and with appropriate retesting. Subgroup analyses were performed for patients who were pregnant and tested positive for Trichomonas vaginalis.

RESULTS

Among the 8809 patients tested for Trichomonas vaginalis, 799 (9.1%) tested positive at least once during the study. Factors associated with trichomoniasis included identifying as non-Hispanic Black (adjusted odds ratio, 3.13; 95% confidence interval, 2.52-3.89), current or former tobacco smoking (adjusted odds ratio, 2.27; 95% confidence interval, 1.94-2.65), and single marital status (adjusted odds ratio, 1.96; 95% confidence interval, 1.51-2.56). Similar associated factors were found in the pregnant subgroup analysis. For women with trichomoniasis, guideline-concordant retesting rates were low across the entire population, with only 27% (214/799) of patients retested within the recommended time frame; 42% (82/194) of the pregnant subgroup underwent guideline-concordant retesting. Non-Hispanic Black women had significantly lower odds of undergoing guideline-recommended retesting than non-Hispanic White women (adjusted odds ratio, 0.54; 95% confidence interval, 0.31-0.92). Among patients tested according to guideline recommendations, we found a high rate of Trichomonas vaginalis positivity at retesting: 24% in the entire cohort (51/214) and 33% in the pregnant subgroup (27/82).

CONCLUSION

Trichomonas vaginalis infection was identified at a high frequency in a diverse, urban hospital-based obstetrics and gynecology clinic population. Opportunities exist to improve on equitable and guideline-concordant retesting of patients with trichomoniasis.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

Strong association between higher-risk sex and HIV prevalence at the regional level: an ecological study of 27 sub-Saharan African countries

Background: It is unclear why HIV prevalence varies by nearly two orders of magnitude between regions within countries in sub-Saharan Africa. In this ecological study, we assess if HIV prevalence by region is associated with any of four markers of higher risk sexual behavior: lifetime number of partners, multiple partners in past year, higher risk sex (defined as sex with non-cohabiting, non-marital partners) and age at debut. Methods: We performed Pearson's correlation between the 4 behavioral risk factors and HIV prevalence by region in 47 nationally representative surveys from 27 sub-Saharan African countries, separately by gender. In addition, principal components analysis was used to reduce the eight risk factors (four for each gender) to two principal components (PCs). Mixed effects linear regression was used to assess the relationship between the resulting two PCs and HIV prevalence after controlling for the prevalence of male circumcision. Results: HIV prevalence varied by a median 3.7 fold (IQR 2.9-7.9) between regions within countries. HIV prevalence was strongly associated with higher risk sex and, to a lesser extent, the other risk factors evaluated. Both PCs were strongly associated with HIV prevalence when assessed via linear regression. Conclusions: Differences in sexual behavior may underpin the large differences in HIV-prevalence between subpopulation within sub-Saharan African countries.

It's the network, stupid: a population's sexual network connectivity determines its STI prevalence

There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.

The role of sexual networks in studies of how BV and STIs increase the risk of subsequent reinfection

Prior studies have demonstrated that both bacterial vaginosis (BV) and sexually transmitted infections (STIs) are strong independent risk factors for subsequent STI. In observational studies of this biological enhancement (BE) hypothesis, it is important to adjust for the risk of STI exposure so that the independent effect of BE can be assessed. We sought to model if two markers of local sexual network (partner concurrency and cumulative number of STIs) represented residual confounding in the models of risk for subsequent infection in a study that screened 3620 women for STIs every 3 months for a year. Mixed-effects logistic regression was used to calculate the odds ratios for an incident diagnosis of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and BV following a diagnosis of any of these four at the prior visit, controlling for the cumulative number of STIs and partner concurrency variables. We found that partner concurrency and cumulative number of STIs were each associated with incident infection, and in general, controlling for these variables reduced the strength of the association between prior and incident infections. We conclude that the frequently found association between prior and incident STIs is associated with both BE and sexual network structure.

Strong associations between national prevalence of various STIs suggests sexual network connectivity is a common underpinning risk factor

Background

If national peak Human Immunodeficiency Virus (HIV) prevalence is positively associated with the prevalence of other sexually transmitted infections (STIs) from before or early on in the HIV epidemics this would suggest common underlying drivers.

Methods

Pearson’s correlations were calculated between the prevalence of seven STIs at a country-level: chlamydia, gonorrhoea, trichomoniasis, syphilis, bacterial vaginosis, herpes simplex virus-2 (HSV-2) and HIV.

Results

The prevalence of all the STIs was highest in the sub-Saharan African region excluding chlamydia. The prevalence of all seven STIs were positively correlated excluding chlamydia. The correlations were strongest for HIV-HSV-2 (r = 0.85, P < 0.0001) and HSV-2-trichomoniasis (r = 0.82, P < 0.0001).

Conclusion

Our results of a generally positive association between the prevalences of a range of STIs suggests that higher prevalences were driven by common underlying determinants. We review different types of evidence which suggest that differential sexual connectivity is a plausible common determinant.