Background: As elsewhere in the US, San Francisco has seen STD increases alongside recent declines in HIV rates. This dichotomy raises the question of whether increases in reported STDs can be explained by increased testing or condomless sex. Data from the municipal STD clinic provide routinely available data to examine practices and trends.
Methods: To compare testing, positivity, and risk trends between January 2005-December 2010 and January 2011-June 2016, the analysis included all SF City Clinic (SFCC) visits among males. Patients reported the number of condomless anal sex partners for the previous 3 months. We combined all rectal chlamydia and gonorrhea tests by visit, counting positivity once regardless of test(s). We examined changes in visits and tests (projected through 2016) using t-tests and changes in positivity, behaviors, and mean number of partners using chi-square tests.
Results: The average annual number of visits decreased from 2005-2010 (n=16,632) to 2011-2016 (n=14,019;p<0.01). Rectal test volume did not change (n=3967 vs 4314,p>0.01), but positivity increased (4.2% vs 4.8%,p<0.01). The proportion of patient-visits when any receptive anal (RA) sex was reported increased between the two time periods from 16.1% to 30.7% (p<0.01), among which condomless RA sex also increased, from 26.5% to 39.2% (p<0.01). The average number of condomless RA sex partners in the past 3 months increased from 0.6 to 1.1 (p<0.01). Trends were similar among only males who received a rectal test (high risk proxy) during their visits.
Conclusions: Rectal CT/GC positivity increased significantly during 2011-2016. Whereas testing volume was unchanged, significant increases were identified in RA sex, condomless RA sex, and the number of condomless RA sex partners. Changes in sexual behaviors seen after 2010 have significant implications for STD prevention and sexual health messaging. Monitoring changes in risk need not rely on behavioral surveys; STD clinic data can inform programs and policies for many jurisdictions.