Dual HIV risk: receptive syringe sharing and unprotected sex among HIV-negative injection drug users in New York City.

HIV-negative injection drug users (IDUs) who engage in both receptive syringe sharing and unprotected sex ("dual HIV risk") are at high risk of HIV infection. In a cross-sectional study conducted in New York City in 2009, active IDUs aged ≥18 years were recruited using respondent-driven sampling, interviewed, and tested for HIV. Participants who tested HIV-negative and did not self-report as positive were analyzed (N = 439). Adjusted odds ratios (aOR) and 95 % confidence intervals (95 % CI) were estimated using multinomial logistic regression. The sample was: 77.7 % male; 54.4 % Hispanic, 36.9 % white, and 8.7 % African-American/black. Dual risk was engaged in by 26.2 %, receptive syringe sharing only by 3.2 %, unprotected sex only by 49.4 %, and neither by 21.2 %. Variables independently associated with engaging in dual risk versus neither included Hispanic ethnicity (vs. white) (aOR = 2.0, 95 % CI = 1.0-4.0), married or cohabiting (aOR = 6.3, 95 % CI = 2.5-15.9), homelessness (aOR = 3.4, 95 % CI = 1.6-7.1), ≥2 sex partners (aOR = 8.7, 95 % CI = 4.4-17.3), ≥2 injecting partners (aOR = 2.9, 95 % CI = 1.5-5.8), and using only sterile syringe sources (protective) (aOR = 0.5, 95 % CI = 0.2-0.9). A majority of IDUs engaged in HIV risk behaviors, and a quarter in dual risk. Interventions among IDUs should simultaneously promote the consistent use of sterile syringes and of condoms.