A method for identifying persons at high risk for sexually transmitted infections: opportunity for targeting intervention.

Objectives: The purpose of this study was to develop a method to identify persons at high risk for acquiring new sexually transmitted infections.

Methods: Computerized medical records from sexually transmitted disease clinics in Dade County, Florida, were used to conduct a retrospective cohort study. For all patients who visited in 1987, risk factors were identified for returning to the clinics within a year with a new sexually transmitted infection. Predictor variables were derived from the index visit and any visits in the year prior to the index visit. Logistic regression was used to develop a model that was applied to all patients who attended in 1989.

Results: Of 24,439 patients attending in 1987, 18.5% returned within a year with a new infection. Return rates were highest for 15- to 19-year-old Black males (31.8%). The highest odds ratios for returning were a diagnosis or treatment for an infection in the previous year and a diagnosis or treatment for infection at the index visit. The patients predicted to be at highest risk had a 39% return rate. There were as many new infections among the 2893 patients at highest risk as there were among the 13,326 patients at lowest risk.

Conclusions: We developed a model that identifies persons at very high risk for sexually transmitted infection. These persons should be targeted for intensive intervention to reduce their risk.