Screening emergency department patients for sexually transmitted diseases (STDs) can help identify undiagnosed infections, but because populations vary, screening programs have to be tailored to particular settings.1 At two Baltimore emergency departments, one in the inner city and one in another urban area, comparable proportions of patients who agreed to be screened tested positive for gonorrhea or chlamydia, but most of the risk factors associated with infection varied. In the inner-city facility, patients aged 25 or younger, individuals with a history of STDs and those who had recently had multiple sex partners had elevated risks of infection; in the other facility, women and those reporting multiple recent partners were at increased risk. Factors associated with declining to be screened also varied between populations.

The inner-city emergency department is in an area of Baltimore with a high STD incidence and provides care to a largely black, underserved population aged 18-44. By contrast, the non-inner city facility is in a part of the city with a moderate incidence of STDs, and serves a clientele who are mainly white and aged 14-39. Men and women seeking medical treatment who were not critically ill and were able to give consent were eligible for study participation; the study was conducted in 1998 in the inner-city facility and in 2000 at the urban site. Participants completed interviews covering demographic and behavioral characteristics, and provided urine samples, which were tested for gonorrhea and chlamydia by ligase chain reaction.

In all, 454 patients aged 18-31 visiting the inner-city facility (77% of those approached during the study period) and 298 visiting the urban site (61%) participated in the screening program. (The researchers focused on 18-31-year-olds because most infections occur in this group.) On average, individuals in both populations were about 24 years of age. The inner-city population had a higher proportion of women than the urban population (63% vs. 52%), as well as a higher proportion of black patients (90% vs. 37%). Nearly three in five participants in each setting had health insurance, but those in the inner city were more likely than others to say that they used the emergency department as their regular source of health care (58% vs. 48%).

Fourteen percent of participants in each setting tested positive for gonorrhea or chlamydia, but several significant differences emerged between settings in behavioral factors for disease. Patients at the urban emergency department scored higher than inner-city men and women on a standard instrument assessing alcohol use and were more likely to give positive responses to at least two questions on this instrument (17% vs. 10%); they were less likely to report having had a new sex partner in the past 90 days (16% vs. 26%) and to say that they had ever had an STD (31% vs. 52%). Marginally higher proportions of participants at the inner-city site than at the urban facility were visiting the emergency department because of a genital discharge (6% vs. 3%) and received treatment for gonorrhea or chlamydia at their initial visit (10% vs. 6%).

Results of multivariate logistic regression analyses revealed that the factors associated with 18-31-year-old patients' likelihood of testing positive for gonorrhea or chlamydia differed in the two settings. Among inner-city patients, the odds of testing positive were roughly doubled among men and women aged 25 or younger, those who had ever had an STD and those who had had two or more sex partners in the past 90 days (odds ratios, 2.0-2.2). Participants at the urban facility who reported multiple recent partners also were at increased risk of infection (odds ratio, 2.8); the only other significant predictor of infection in this population was being female (2.5).

Logistic regression analysis also demonstrated that factors associated with refusal to participate in STD screening at an emergency visit varied by setting. At the inner-city facility, the odds of refusal were significantly elevated among patients whose visit was not prompted by genitourinary symptoms (odds ratio, 2.8), and were reduced among black patients (0.5) and patients approached on particular days of the week (0.3-0.4). Patients at the urban site likewise had reduced odds of refusing if they were black (0.7) and increased odds of refusing if they were not seeking help for a genitourinary problem (1.7). In addition, women and participants aged 27-31 were more likely than men and younger patients to decline screening (1.6 and 1.5, respectively), and those approached during daytime hours were more likely to decline than those visiting the facility after six in the evening (2.2).

According to the investigators, given the prevalence not only of STDs but of substance use detected in this study, the emergency department "presents an intervention opportunity...for a number of public health and preventive services," especially for patients who use it as their regular source of health care. However, they caution that unmeasured or unmeasurable factors affect the results and generalizability of screening programs based in emergency departments. Therefore, they encourage an assessment of a given emergency department population "before implementation of a wide-scale screening program that uses parameters developed in another setting." --D. Hollander


1. Mehta SD et al., Generalizability of STD screening in urban emergency departments: comparison of results from inner city and urban sites in Baltimore, Maryland, Sexually Transmitted Diseases, 2003, 30(2):143-148.