Background The US National HIV Behavioral Surveillance (NHBS) system conducts venue-based sampling every three years of men who ever had a male sexual partner (i.e., men who have sex with men–MSM). In San Francisco, MSM attendees of the municipal STD clinic might serve as a proxy population during non-survey years.

Methods We compared select questions from the 510 participants of the NHBS MSM-San Francisco survey (07/21–12/19/2011) to similar measures from 1807 MSM who visited the San Francisco City Clinic (SFCC) during the same time period. One visit was randomly selected among clients who had multiple SFCC visits during the study period. We compared the two groups’ demographics and HIV/STD-related history. Data were self-reported except SFCC STD history, which was laboratory-confirmed.

Results SFCC clients were more likely to be younger, non-white, un-insured, and self-identify as straight. NHBS participants were more likely to report a lifetime history of injection drug use and 12-month non-injection drug use of cocaine, crack, poppers, and erectile dysfunction medications. Methamphetamine use was not statistically different. Approximately 44% of both samples reported ≥ 6 male partners in the past year. The two groups did not differ on history of HIV testing, HIV-positive status, current HAART use among known HIV positives, or PEP use in the past year among HIV negatives. Self-reported syphilis or chlamydia was less likely among NHBS participants than laboratory-confirmed diagnoses among SFCC clients; gonorrhoea positivity did not differ statistically.

Discussion NHBS and SFCC MSM similarly reported several key behavioural surveillance factors. Readily available non-survey surveillance data may be useful for monitoring trends among the San Francisco MSM population and informing policy and programmes. Future efforts should explore how STD clinic data can be used to supplement behavioural surveillance.