Discord, discordance, and concurrency: comparing individual and partnership-level analyses of new partnerships of young adults at risk of sexually transmitted infections.

BACKGROUND AND OBJECTIVES Partnerships that are discordant by demographic and behavioral characteristics or are concurrent may facilitate transmission of sexually transmitted infections (STIs) by bridging sexual networks. GOAL : The goal of this study was to examine if STI risk within partnerships is associated with discordance and concurrency using the partnership as the unit of analysis. STUDY One hundred ninety-two individuals, in 96 new partnerships, recruited from sexually transmitted disease and family planning clinics, underwent a computer-assisted interview; were tested for chlamydia, gonorrhea, and trichomonas; and their medical records were reviewed. Partnership variables for discordance by ethnicity, education level, number of lifetime partners, and relationship commitment, as well as concurrency and consistent condom use were tested for associations with partnership STI by chi-squared analysis and logistic regression. Associations between individual level STI, individual characteristics, relationship commitment, and concurrency were tested in bivariate and multivariate models. RESULTS STI was detected in 22% of partnerships; discordance for demographics or relationship commitment was reported in 40% to 50%; and partner concurrency in 26%. Few partnerships (18%) reported consistent condom use in the prior month. In multivariate analyses, partnership-level STI was associated with discordance by ethnicity (odds ratio [OR], 3.4; P = 0.04), commitment (OR, 4.2; P = 0.02), number of lifetime partners (OR, 4.9; P = 0.01), and concurrency (OR, 3.8; P = 0.03). Individual-level STI was associated with the individual's concurrency and Hispanic ethnicity. CONCLUSIONS Discordance and concurrency are associated with STI at the partnership level and may reflect bridging between high- and low-risk STI networks. Partnership factors allowed additional assessment of STI risk over individual factors, suggesting that data on partnerships may identify individuals linked to risky networks.