Serving as a complement to the ongoing HIV seroprevalence studies in sexually transmitted disease (STD) clinics, the Record-Based Incidence Study (RBIS) was initiated in 1994 to track, prospectively, the course of the HIV epidemic among a population considered at high risk for HIV infection. Data collected through conduct of the RBIS have proven vital in terms of monitoring emerging trends among STD patients in Los Angeles County. Because seroprevalence data are limited in projecting the future course of the HIV epidemic, HIV incidence data are of particular importance for planning the allocation of scarce resources as well as the timely development of prevention programs that specifically target those at greatest risk of acquiring or transmitting HIV.
- To develop standard procedures for conducting record-based HIV seroincidence surveys in STD clinic populations.
- To estimate the incidence of HIV in individuals who have received multiple HIV tests associated with STD clinic visits.
- To assess risk behaviors associated with HIV seroconversion among patients attending STD clinics in Los Angeles County.
- To monitor trends in HIV seroincidence among patients attending STD clinics in Los Angeles County.
- To estimate the risk of HIV infection associated with genital ulcers and lesions.
RBIS is a prospective, record-based cohort study are conducted in accordance with the CDC Protocol Guidelines for Estimating HIV Seroincidence in Persons Attending Sexually Transmitted Disease Clinics in the United States, April 1994. Each STD patient visiting any of the four participating clinics (Central Health Center, Curtis Tucker Health Center, Hollywood-Wilshire Health Center, or South Heath Center) is offered confidential HIV counseling and testing. Patients who accept a confidential test complete an interviewer-administered, demographic and risk behavior survey. This survey supplements the patient's medical chart that documents physical exam assessments, STD history, and STD and HIV laboratory results.
All STD patients accepting a confidential HIV test at the four participating clinics will be entered into a passive cohort and the medical records will be monitored daily for repeat confidential HIV test visits. Incident HIV infections will be detected when a patient receives more than one confidential HIV test as a result of repeat STD clinic visits. Incident infections will be defined as a positive HIV antibody test result preceded by at least one negative HIV test result. Patients with a baseline HIV test who return to the clinic for a new disease episode(s) but never accept a second confidential HIV test will be censored from the cohort and will not contribute to person-time incidence calculations.
Trained data abstractors are assigned to cover the four participating clinics and collect medical chart information using a computerized abstraction instrument designed to minimize keystroke errors and ensure high quality data. Medical record data are uploaded weekly into a database maintained at the HIV Epidemiology Program and the data are reduced to the required CDC core variables and subsequently merged to confidential HIV test data using a unique HIV test identification number.
Trista Bingham, M.P.H.
Shannon Hanrahan, M.A.
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