Chlamydia trachomatis among patients infected with and treated for Neisseria gonorrhoeae in sexually transmitted disease clinics in the United States

Background: For two decades, treatment guidelines for sexually transmitted diseases (STDs) have recommended empirical co-treatment for chlamydia when patients are treated for gonorrhea. Because the epidemiology of and diagnostic testing for STDs have changed over time, co-treatment may no longer be needed as a clinical or public health strategy. Objective: To assess the prevalence of chlamydia among patients at STD clinics who are infected with and treated for Neisseria gonorrhoeae and to determine whether co-treatment recommendations are still justified. Design: Cross-sectional analysis of data from a multisite study. Setting: Five public STD clinics (Baltimore, Maryland; Denver, Colorado; Long Beach, California; Newark, New Jersey; and San Francisco, California), July 1993 through October 1995. Patients: 3885 heterosexual patients (2184 men and 1701 women) who agreed to participate in a trial of counseling interventions and had conclusive results from diagnostic tests for gonorrhea and chlamydia performed routinely as part of the trial. Measurements: infection with Chlamydia trachomatis as determined by polymerase chain reaction. Results: Chlamydia trachomatis was detected in 20% (95% CI, 16% to 24%) of 411 men and 42% (CI, 35% to 50%) of 151 women with laboratory-confirmed N. gonorrhoeae. Chlamydia trachomatis was detected in 19% (CI, 15% to 22%) of 410 men and 35% (CI, 28% to 43%) of 154 women with treatment indications for gonorrhea who would not otherwise have been treated for chlamydia: chlamydia prevalence among these patients was significantly higher than among patients without treatment indications for either gonorrhea or chlamydia: 7% in men and 9% in women (relative risk, 2.58 [CI, 1.92 to 3.47] and 4.12 [CI, 3.05 to 5.57], respectively). Conclusion: The frequent presence of chlamydia among patients at STD clinics who received treatment for gonorrhea, including sex partners of gonorrhea-infected patients, supports continuing current recommendations for co-treatment.