Background Few US health departments provide partner service (PS) to persons with gonorrhoea (GC) or chlamydia (CT). We sought to define the potential utility of providing PS to MSM with GC or CT as an HIV prevention intervention.

Methods We analysed public health reporting and PS data from WA State, USA, 2007–2010 to evaluate whether provider initiated case reports could identify MSM with GC or CT, to assess engagement in HIV care among MSM with STIs previously diagnosed with HIV, and to determine how often MSM HIV test when diagnosed with GC or CT. Estimates of previously diagnosed HIV, engagement with care, and HIV testing were derived from a random sample of cases weighted to reflect cases' residence and receipt of care in the King County STD clinic. We linked STI and HIV reporting data to estimate the risk of subsequent HIV diagnoses among MSM reported with GC or CT.

Results Medical providers recorded the gender of cases' sex partners on 19 000 (68%) of 27 762 case reports on men with GC or CT, 4281 (22%) of which indicated that the case had sex with men. Case report and PS interview data on cases' sexual orientation agreed in 6711 (96%) of 6999 cases for which both data sources were available (κ=0.90). Agreement was higher for STD clinic cases (κ=0.98) than for other King County cases (κ=0.86) or among men outside of King County (κ=0.68). Among a random sample of 1103 cases identified as MSM in both case report and PS data, 25% were previously diagnosed with HIV, of whom 87% were in care and 63% were on antiretrovirals. Among MSM without a prior HIV diagnosis, 55% reported that they HIV tested when diagnosed with GC or CT. The proportion of MSM who HIV tested was higher STD clinic cases (82%) than among other King County MSM (57%) or MSM outside of King County (41%) (p<0.0001). Nineteen (3.3%) of 583 tested MSM were newly diagnosed with HIV. Among MSM without a prior HIV diagnosis who were not diagnosed with HIV at time of their GC or CT diagnosis, the subsequent rate of new HIV diagnosis was 2.5/100 person years. Among 1421 MSM diagnosed with HIV in WA State 2007–2010, 6.3%, 9.6%, and 11.9% had been reported with GC or CT in the 1, 2, and 3 years prior to HIV diagnosis, respectively.

Conclusions MSM with GC and CT are an identifiable and accessible population at high risk for HIV acquisition and transmission who might benefit from efforts to increase HIV testing frequency and linkage to HIV care. Expanding PS for bacterial STI should be evaluated as a means to achieve these goals.