Risk behaviors and HIV incidence among repeat testers at publicly funded HIV testing sites in San Francisco

Objective: More than 25% of HIV tests are for individuals who have previously been tested. To characterize repeat testers, we 1) estimated the seroincidence of HIV infection, stratified by risk behavior, and examined the association between 2) testing rates and risk level and 3) repeat testing and tester characteristics. Methods: Records from HIV counseling and testing (C&T) sites were reviewed. Seroincidence was estimated by linking results of current test with date of last reported HIV negative test. A risk hierarchy of behaviors was created. Repeat testing rates were calculated for each risk level strata. Multivariate models explored the association of repeat testing with tester characteristics. Results: The HIV seroincidence among repeaters was 1.3 per 100 person-years (range 0.7-7.0 per 100 person-years). The high-risk level subject had a repeater rate of 92%, with 5.3 tests/person and was more likely (odds ratio = 4.96, 95% confidence interval 3.8-6.5) to have tested two or more times, compared with those in the low risk Group. Conclusion: The highest users of repeat testing are those who are practicing the highest risk behaviors and have the highest incidence of HIV. This suggests that prevention messages should be modified to more explicitly address the behaviors that are putting individuals at high risk for HIV.