Genital Chlamydia infections in sexually active female adolescents: do we really need to screen everyone?

PURPOSE

To evaluate current Chlamydia trachomatis screening guidelines, which recommend that all sexually active female adolescents undergoing a pelvic examination be tested for chlamydial infection, and determine if instead providers should target particular subpopulations of these adolescents.

METHODS

Data were collected from 148,650 sexually active females, ages 15-19 years, tested by direct immunofluorescent antibody in 160 family planning clinics from 1988-92. Trends in chlamydia prevalence by demographic, behavioral, and clinical risk factors were analyzed. Logistic regression modeling was used to identify selective screening criteria. Predictive models were developed for all years combined, as well as for the years when prevalence was highest and lowest.

RESULTS

The prevalence of C. trachomatis in this population was 10%, with a 42% decrease (13.2-7.6%) over the 5-year period. Logistic regression identified nine demographic, behavioral, and clinical predictors (p < 0.0001) associated with chlamydial infections. Predictor models from the highest and lowest prevalence years varied little from the combined model. Individual year predictor models showed poor sensitivity and were similar for these 2 years. The screening criteria could not identify a group of adolescents with a prevalence less than 6%.

CONCLUSIONS

Several individual risk factors were strongly associated with C. trachomatis, but no single risk factor or combination of risk factors used for selective screening could identify more than 42% of infections in our population. These findings support earlier national recommendations and the need for universal screening of sexually active female adolescents.