High Lifetime Prevalence of Syphilis in Men Who Have Sex With Men and Transgender Women Versus Low Lifetime Prevalence in Female Sex Workers in Lima, Peru

How to apply variable selection machine learning algorithms with multiply imputed data: A missing discussion

Psychological researchers often use standard linear regression to identify relevant predictors of an outcome of interest, but challenges emerge with incomplete data and growing numbers of candidate predictors. Regularization methods like the LASSO can reduce the risk of overfitting, increase model interpretability, and improve prediction in future samples; however, handling missing data when using regularization-based variable selection methods is complicated. Using listwise deletion or an ad hoc imputation strategy to deal with missing data when using regularization methods can lead to loss of precision, substantial bias, and a reduction in predictive ability. In this tutorial, we describe three approaches for fitting a LASSO when using multiple imputation to handle missing data and illustrate how to implement these approaches in practice with an applied example. We discuss implications of each approach and describe additional research that would help solidify recommendations for best practices. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Substance use and other correlates of HIV infection among transwomen and men who have sex with men in Perú: Implications for targeted HIV prevention strategies for transwomen

Characterization of HIV risk factors among transwomen and men who have sex with men (MSM) should be assessed separately and independently. However, due to several constraints, these populations continue to be conflated in clinical research and data. There are limited datasets globally powered to make such comparisons. The study aimed to use one of the largest surveys of transwomen and MSM in Latin America to determine differences in HIV risk and related correlates between the two populations. Secondary data analysis was completed using a cross-sectional biobehavioral survey of 4413 MSM and 714 transwomen living in Perú. Chi Square analysis of selected HIV correlates was conducted to examine differences between transwomen and MSM. Additionally, stratified binary logistic regression was used to split data for further comparative analyses of correlates associated with transwomen and MSM separately. HIV prevalence among transwomen was two-fold greater than among MSM (14.9% vs. 7.0%, p<0.001). Transwomen had a higher prevalence of most HIV risk factors assessed, including presence of alcohol dependence (16.4% vs. 19.0%; p < .001) and drug use in the past 3 months (17.0% vs. 14.9%). MSM were more likely to use marijuana (68.0% vs. 50.0%, p < .001), and transwomen were more likely to engage in inhaled cocaine use (70.0% vs. 51.1%, p < .001). The regression exposed differences in correlates driving sub-epidemics in transwomen vs. MSM, with a trend of substance use increasing HIV risk for transwomen only. Transwomen were more likely to be HIV-infected and had different risk factors from MSM. Targeted prevention strategies are needed for transwomen that are at highest risk. Additionally, further research is needed to determine if these observations in Perú regarding substance use patterns and the role of substance use in HIV risk relate to other trans populations globally.

High prevalence of syphilis in women, minors and precarious patients: a cross-sectional study in a Reunion Island sexually transmitted infection clinic, 2017-2020

BACKGROUND

Syphilis is a sexually transmitted infection (STI) with a global prevalence estimated at 0.5% in 2012. Syphilis has been on the rise among men who have sex with men (MSM) in high-income countries and remains at endemic levels in low- and middle-income countries. This trend, however, has not been observed in Reunion Island.

OBJECTIVES

To determine the prevalence, clinical characteristics and risk factors of syphilis in at-risk patients visiting the South Reunion STI clinic in Reunion Island.

METHODS

This monocentric cross-sectional study included all patients who visited our STI clinic between 2017 and 2020. Syphilis serology was performed on all included patients, and data were collected using a standardized self-administered questionnaire.

RESULTS

Over the 3-year study period, 2593 patients were enrolled. The prevalence of syphilis was 7.52% (n = 195, 95% CI, 6.50-8.65%) in the overall study population, 11.76% (n = 18, 95% CI, 6.97-18.59%) in minors (aged under 18 years) and 36.36% (n = 16, 95% CI, 21-59%) in pregnant women. The risk factors identified in multivariate analysis were being female [adjusted Prevalence Ratio (aPR) 1.85, 95% CI, 1.10-3.11], being MSM (aPR 2.87, 95% CI, 1.71-4.80), being aged under 18 years (aPR 3.54, 95% CI, 1.90-6.57), living in precarious conditions [aPR 3.12, 95% CI, 2.11-4.62] and being born in Reunion Island (aPR 2.43, 95% CI, 1.42-4.13). The clinical presentation was heterogeneous (plaques and papules, chancre, atypical ulcerations, multiple ulcerations, condyloma lata, etc.).

CONCLUSIONS

These findings suggest a high prevalence of syphilis in at-risk patients visiting our STI clinic. Unlike the situation in other high-income countries, the people most at risk of syphilis in Reunion Island are local-born residents, minors, women and precarious patients. This is a source of concern, especially given the risk of resurgence of congenital syphilis on the island.