Background: Serosorting is increasingly assessed in studies of men who have sex with men (MSM). Most research studies have measured serosorting by combining reported unprotected anal intercourse (UAI) and the occurrence of participant and partner same HIV status (seroconcordance). The Centers for Disease Control and Prevention's definition of serosorting also incorporates intent to be in such a partnership, although few studies incorporate both intent and behavior into their measures.
Methods: Using data from a national, online survey of 3519 US MSM, we assessed the role of intention in seroconcordant partnerships, as measured by participant rating of the importance of shared serostatus when selecting a sex partner.
Results: For HIV+ men, 30% partnerships were seroconcordant; of these, 48% reported intent to be in such a partnership (intentional seroconcordance). For HIV- men, 64% partnerships were seroconcordant; of these, 80% reported intentional seroconcordance. Intentional seroconcordance was associated with UAI for HIV+ partnerships [odds ratio (OR): 1.9; 95% confidence interval (CI): 1.3 to 2.9] but not significant for HIV- partnerships (OR: 1.1; CI: 0.99 to 1.3). In separate models where intent was not considered, seroconcordance was associated with UAI for HIV+ partnerships (OR: 3.2; 95% CI: 2.2 to 4.6) and for HIV- partnerships (OR: 1.2; 95% CI: 1.0 to 1.3; P = 0.03).
Conclusions: Regardless of intentionality, seroconcordance was strongly associated with UAI for HIV+ men and weakly associated with UAI for HIV- men. Intentional seroconcordance was not associated with UAI more strongly than was seroconcordance in absence of consideration of intent. Intentionality may not be a critical element of the relationship between seroconcordance and UAI.