Overdiagnosis of Urinary Tract Infection and Underdiagnosis of Sexually Transmitted Infection in Adult Women Presenting to an Emergency Department

Abstract

Urinary tract infections (UTIs) and sexually transmitted infections (STIs) are commonly diagnosed in emergency departments (EDs). Distinguishing between these syndromes can be challenging because of overlapping symptomatology and because both are associated with abnormalities on urinalysis (UA). We conducted a 2-month observational cohort study to determine the accuracy of clinical diagnoses of UTI and STI in adult women presenting with genitourinary (GU) symptoms or diagnosed with GU infections at an urban academic ED. For all urine specimens, UA, culture, and nucleic acid amplification testing for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis were performed. Of 264 women studied, providers diagnosed 175 (66%) with UTIs, 100 (57%) of whom were treated without performing a urine culture during routine care. Combining routine care and study-performed urine cultures, only 84 (48%) of these women had a positive urine culture. Sixty (23%) of the 264 women studied had one or more positive STI tests, 22 (37%) of whom did not receive treatment for an STI within 7 days of the ED visit. Fourteen (64%) of these 22 women were diagnosed with a UTI instead of an STI. Ninety-two percent of the women studied had an abnormal UA finding (greater-than-trace leukocyte esterase level, positive nitrite test result, or pyuria). The positive and negative predictive values of an abnormal UA finding were 41 and 76%, respectively. In this population, empirical therapy for UTI without urine culture testing and overdiagnosis of UTI were common and associated with unnecessary antibiotic exposure and missed STI diagnoses. Abnormal UA findings were common and not predictive of positive urine cultures.

FIG 1

Urine culture and STI testing results stratified by provider diagnosis. Data are number of patients positive/number of patients tested (%), unless otherwise indicated. Pos, positive; Neg, negative; CT, C. trachomatis; TV, T. vaginalis; GC, N. gonorrhoeae. The superscript letter a indicates that two patients had both C. trachomatis- and T. vaginalis-positive tests, and the superscript letter b indicates that one patient had both C. trachomatis- and T. vaginalis-positive tests.