Objectives: Urinary tract infections (UTIs) and early pelvic infections due to sexually transmitted disease (STD) may cause similar symptoms. Therefore, a simple history and urine dip to establish a diagnosis of UTI may result in overtreatment of UTIs and undertreatment of STDs. The objective of this study was to determine the proportion of women with symptoms suggestive of a UTI who are urine culture positive versus urine culture negative, the prevalence of STDs between groups, and if elements of the history or examination may predict those requiring STD screening.
Methods: This was a prospective cohort study in an urban emergency department. Women 18-55 years of age with urinary frequency, urgency, dysuria, and no new vaginal discharge or change in discharge were enrolled. The following were performed: detailed history; bladder catheterization for urinalysis, urine dip, and urine culture; pelvic examination and cervical samples for gonorrhea and Chlamydia trachomatis DNA ligase; and wet mount examinations. Main outcome measurements were the percentage of women who were urine culture positive (using low count criteria of 10(2) colony-forming units [CFU]/mL), the proportion of STDs between urine culture groups, and univariate analysis and logistic regression of historical and examination elements.
Results: Ninety-two patients were enrolled; the mean age was 26 years (range, 18-51 years). All had samples for DNA ligase (one quantity not sufficient) and urinalysis or urine dip, while 75 of 92 had urine cultures performed. A total of 57.3% (43/75) were urine culture positive at 10(2) CFU/mL, while the STD rate for those with urine cultures was 17.3% (13/75). There was no statistically significant difference in the number of STDs between urine culture positive and urine culture negative groups. The only variable on logistic regression predictive of an STD (based on all 91 patients) was more than one sex partner in the past year (p = 0.013). No other element of the history or pelvic examination helped differentiate those who tested positive for an STD.
Conclusions: A total of 17.3% of women with symptoms of a UTI in this study had an STD, while only 57.3% were urine culture positive by catheterization using low count criteria. The proportion of STDs between those with and without a UTI was not significantly different.