title: The risk of stable partnerships: associations between partnership characteristics and unprotected anal intercourse among men who have sex with men and transgender women recently diagnosed with HIV and/or STI in Lima, Peru.
abstract: BACKGROUND
  Partnership type is an important factor associated with unprotected anal intercourse (UAI) and subsequent risk for HIV and sexually transmitted infections (STI). We examined the association of partnership type with UAI among men who have sex with men (MSM) and male-to-female transgender women (TGW) in Lima, Peru, recently diagnosed with HIV and/or STI.
  
  
  METHODS
  We report data from a cross-sectional analysis of MSM and TGW recently diagnosed with HIV and/or STI in Lima, Peru between 2011 and 2012. We surveyed participants regarding UAI with up to their three most recent sexual partners according to partner type. Multivariable Generalized Estimate Equating (GEE) models with Poisson distribution were used to estimate prevalence ratios (PR) for UAI according to partner type.
  
  
  RESULTS
  Among 339 MSM and TGW recently diagnosed with HIV and/or STI (mean age: 30.6 years, SD 9.0), 65.5% self-identified as homosexual/gay, 16.0% as bisexual, 15.2% as male-to-female transgender, and 3.3% as heterosexual. Participants provided information on 893 recent male or TGW partners with whom they had engaged in insertive or receptive anal intercourse: 28.9% stable partners, 56.4% non-stable/non-transactional partners (i.e. casual or anonymous), and 14.7% transactional partners (i.e. transactional sex client or sex worker). Unprotected anal intercourse was reported with 41.3% of all partners. In multivariable analysis, factors associated with UAI included partnership type (non-stable/non-transactional partner APR 0.73, [95% CI 0.59-0.91], transactional partner APR 0.53 [0.36-0.78], p<0.05) and the number of previous sexual encounters with the partner (>10 encounters APR 1.43 [1.06-1.92], p<0.05).
  
  
  CONCLUSIONS
  UAI was more commonly reported for stable partners and in partnerships with >10 sexual encounters, suggesting UAI is more prevalent in partnerships with a greater degree of interpersonal commitment. Further research assessing partner-level factors and behavior is critical for improving HIV and/or STI prevention efforts among Peruvian MSM and TGW.
authors.affiliation: David Geffen School of Medicine at UCLA, Department of Medicine, Division of Infectious Diseases and Program in Global Health, Los Angeles, California, United States of America.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Cambou
authors.affiliation: David Geffen School of Medicine at UCLA, Department of Medicine, Division of Infectious Diseases and Program in Global Health, Los Angeles, California, United States of America; Mailman School of Public Health, Columbia University, Department of Sociomedical Sciences, New York, New York, United States of America.
authors.forename: Amaya G
authors.initials: AG
authors.lastname: Perez-Brumer
authors.affiliation: David Geffen School of Medicine at UCLA, Department of Medicine, Division of Infectious Diseases and Program in Global Health, Los Angeles, California, United States of America.
authors.forename: Eddy R
authors.initials: ER
authors.lastname: Segura
authors.affiliation: Asociación Civil Impacta Salud y Educación, Lima, Peru.
authors.forename: H Javier
authors.initials: HJ
authors.lastname: Salvatierra
authors.affiliation: Asociación Civil Impacta Salud y Educación, Lima, Peru.
authors.forename: Javier R
authors.initials: JR
authors.lastname: Lama
authors.affiliation: Asociación Civil Impacta Salud y Educación, Lima, Peru.
authors.forename: Jorge
authors.initials: J
authors.lastname: Sanchez
authors.affiliation: David Geffen School of Medicine at UCLA, Department of Medicine, Division of Infectious Diseases and Program in Global Health, Los Angeles, California, United States of America.
authors.forename: Jesse L
authors.initials: JL
authors.lastname: Clark
mesh_terms: D000328:Adult; D002947:Cities; D003430:Cross-Sectional Studies; D005260:Female; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D015233:Models, Statistical; D010568:Peru / Q000453:epidemiology; D016012:Poisson Distribution; D015995:Prevalence; D018570:Risk Assessment; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012749:Sexually Transmitted Diseases / Q000175:diagnosis / Q000453:epidemiology*; D018454:Spouses; D063106:Transgender Persons; D047568:Unsafe Sex / Q000706:statistics & numerical data*