Factors related to genital Chlamydia trachomatis and its diagnosis by culture in a sexually transmitted disease clinic.

The authors cultured 2,320 patients who attended the Denver Metro Health Clinic for Sexually Transmitted Diseases from September 1981 to June 1983 to determine clinical and epidemiologic factors associated with genital chlamydial infection. Among consecutive heterosexual men with urethral discharge, 226 of 849 (27%) had positive urethral cultures, with rates significantly lower among those with profuse (18%) or purulent (19%) discharges, and higher (37%) among those with symptoms for more than seven days. In a subgroup of men without gonococci, those who had polymorphonuclear leukocytes on smear had higher isolation rates (33%) than those who did not (3%). Among consecutive female patients, 172 of 1,031 (17%) had positive cervical cultures, with rates significantly lower in those who were white (13%), married (7%), or using a diaphragm (0 of 77), and higher in those who were positive for Neisseria gonorrhoeae (38%). There was a marginally significant increased rate of chlamydial isolation among oral contraceptive users only for women aged 20 years or younger. Younger age was significantly associated with chlamydial isolation in both men and women after controlling for sexual activity and other factors. Various patient characteristics can be combined to define subgroups of men and women, with rates of isolation ranging from under 4% to over 60%. These results can be useful in deciding whom to test and whom to treat presumptively in a public health setting.