O11.4 Population-Based HIV Incidence Among Men Diagnosed with Infectious Syphilis, 2000–2011

Background Cohort and cross-sectional studies have shown syphilis is associated with risk for HIV infection. However, population-based estimates of the actual risk for HIV following syphilis infections are lacking. Methods In New York City, HIV and STD surveillance registries are separately maintained. Cases reported to these registries with diagnoses from 2000-June 2010 were matched using a deterministic algorithm. We measured HIV incidence among men following primary or secondary syphilis diagnoses. We calculated time at risk for HIV among men diagnosed with HIV ≥ 60 days after syphilis diagnosis; men without reported HIV were presumed uninfected and censored on 3/31/2011. Abstract O11.4 Table HIV-negative P&S syphilis cases Newly diagnosed HIV Person-years at risk Annual HIV incidence (%) 95% CI (HIV incidence) Total in NYC 3034 426 12850.10 3.32 3.01–3.64 Male 2805 423 11714.18 3.61 3.27–3.97 Age 13–19 178 35 646.12 5.42 3.83–7.45 20–24 449 73 1654.75 4.41 3.48–5.51 25–29 484 83 1897.18 4.37 3.51–5.40 30–34 472 80 2107.84 3.80 3.03–4.70 35–39 489 76 2284.96 3.33 2.64–4.14 40–44 345 43 1511.29 2.85 2.08–3.80 45–49 186 23 742.20 3.10 2.01–4.58 50+ 202 10 869.84 1.15 0.58–2.05 Race/ethnicity White 751 126 3064.03 4.11 3.44–4.88 Black 898 169 3597.64 4.70 4.03–5.45 Hispanic 94 94 2480.61 3.79 3.08–4.62 Other 34 34 960.85 3.54 2.49–4.89 Sexual behaviour/risk MSM 1884 389 7000.55 5.56 5.02–6.13 MSW 373 20 1661.05 1.20 0.76–1.83 Other, IDU, & unknown 548 14 3052.57 0.46 2.61–7.51 Syphilis stage Primary 859 103 3905.50 2.64 2.16–3.18 Secondary 1946 320 7808.68 4.10 3.67–4.57 Bacterial infections Syphilis only 2310 281 9718.04 2.89 2.57–3.24 Syphilis with concurrent CT/GC/LGV 103 12 348.96 3.44 1.86–5.85 Syphilis and subsequent CT/GC/LGV 392 130 1647.18 7.89 6.62–9.24 Year of syphilis 2000 47 9 430.40 2.09 1.02–3.84 2001 133 31 1085.93 2.85 1.97–4.00 2002 186 52 1333.22 3.90 2.94–5.07 2003 231 58 1503.69 3.86 2.96–4.95 2004 274 44 1665.15 2.64 1.94–3.51 2005 255 53 1283.46 4.13 3.12–5.36 2006 272 40 1164.34 3.44 2.49–4.63 2007 360 45 1236.88 3.64 2.69–4.82 2008 443 61 1121.37 5.44 4.20–6.94 2009 406 24 691.97 3.47 2.27–5.08 January-June 2010 198 6 197.78 3.03 1.23–6.31 Results Of 2,805 men with syphilis who contributed 11,714 person-years of follow-up, 423 (15.1%) subsequently acquired HIV; annual incidence was 3.61% (95% CI: 3.27%, 3.97%). Median time to HIV diagnosis was 582 days (range 60–3150). HIV incidence was highest among men who have sex with men (MSM) (5.56%, 95% CI: 5.02%–6.13%), relatively uniform across race/ethnicity and year of syphilis diagnosis, and decreased with increasing age at syphilis diagnosis. HIV incidence was higher among males with secondary compared with primary syphilis (4.10% vs. 2.64%, p < 0.0001). HIV incidence among males with syphilis who were diagnosed with another bacterial STD before HIV (14% of cases) was over double the incidence among those who were concurrently diagnosed (7.89% vs. 3.44%, p = 0.002) or reported only with syphilis (7.89% vs. 2.89%, p < 0.0001) during the analytic period. Conclusions On a population level, one in 20 MSM with syphilis are diagnosed with HIV within a year; highly frequent HIV testing and HIV pre-exposure prophylaxis should be considered for HIV-negative syphilis cases. Secondary syphilis suggests untreated primary lesions; the higher HIV incidence among these cases underscores the importance of appropriate STD/HIV screening and early syphilis detection. Registry matching/integration permits identification of high-risk individuals, such as men repeatedly acquiring STD, for targeting prevention activities.