PUBLICLY FUNDED sexually transmitted disease (STD) clinics provide a variety of services for clients, including diagnosis and treatment for symptomatic individuals, provision of preventative treatment for people recently exposed to infected sexual partners, counseling, and screening for occult infections. STD clinic screening programs usually focus their control efforts on gonorrhea, syphilis, and chlamydial infection. In addition, patients are often offered voluntary testing for human immunodeficiency virus (HIV). Diagnosis and treatment of unsuspected infections identified through screening may prevent transmission of infection to others as well as complications in infected patients. Although screening of high-risk asymptomatic individuals may lead to diagnosis of substantial numbers of otherwise unsuspected infections, the benefit of screening occurs only if infected individuals are notified of their infections, permitting treatment, counseling, and partner notification.
Recent studies from Baltimore suggest that 26% and 29% of patients with positive laboratory screening tests for Chlamydia trachomatis and HIV, respectively, could not be notified of their infections once test results became available.1,2 To explore these issues further, we evaluated the yield of gonorrhea and chlamydial screening performed at a public health STD clinic and the proportion of infected patients detected by screening who could be documented to have received therapy.
All patients attending the Jefferson County Department of Health STD clinic in Birmingham, Alabama are routinely screened for gonorrhea. In contrast, because of limited resources, chlamydial screening is performed primarily in women whose immediate clinical problem does not necessitate antichlamydial therapy; however, a small percentage of men are also screened. Patient care is delivered by clinic nurses who perform the history and physical examination and provide treatment if appropriate according to standardized orders. At the time of their clinic visit, patients for whom screening tests are performed are instructed by the nurse to call for their test results in 2 weeks and are provided with written reminders to call that include the clinic's telephone number, the date of their visit, and their clinic number. Health Department Disease Intervention Staff attempt to notify patients within 5 days of the clinic visit of their positive screening cultures and need for therapy using phone calls, letters, and personal visits. At least two telephone calls and two field visits to the patients' stated address are made as part of efforts to notify them of their infection.
For this study, the Jefferson County Department of Health STD clinic's computerized medical records were reviewed to determine what proportion of patients with positive tests for gonorrhea or chlamydial infection were not treated for their infections at the time of their initial evaluation, and what percentage of those patients received treatment within 30 days of testing. For this study, a positive screening culture was defined as a positive culture for Neisseria gonorrhoeae or C. trachomatis obtained from a patient in whom that particular infection was neither clinically apparent nor treated at the time of the initial clinic visit. The clinic's treatment regimens conform to those outlined in the 1993 STD Treatment Guidelines.3 All patients with indications for gonorrhea treatment (e.g., patients with positive Gram's stain, untreated individuals with prior positive tests, or people who give a history of recent exposure to a sexual partner with gonorrhea) receive dual therapy with either ofloxacin or cefixime plus doxycycline. In addition, because of the high prevalence of gonorrhea in the clinic patient population, women with frank mucopurulent cervicitis are empirically treated for both gonorrhea and chlamydial infection. Men with nongonococcal urethritis or who give a history of recent exposure to a sexual partner with chlamydial infection receive antichlamydial therapy only.
Cultures for N. gonorrhoeae were performed using modified Thayer-Martin media according to standard procedures.4C. trachomatis infections were diagnosed by cell culture in microtiter plates as previously described.5
Medical records were reviewed for the period of January 1, 1994 through June 30, 1995. During this interval, there were 35,643 visits to the STD clinic, including visits for STD evaluation as well as visits solely for HIV counseling and testing. Of the total visits, 18,028 (50.6%) were male patients and 17,615 (49.4%) female patients. Screening cultures were obtained only during an initial STD evaluation visit. Cultures for N. gonorrhoeae were positive for 26% (3271/12,412) of men for whom urethral cultures were obtained and for 12% (1520/12,411) of women for whom endocervical cultures were obtained. C. trachomatis cultures were positive for 12% (387/3222) of men and for 10.5% (1152/10,940) of women who were tested. Among patients with positive cultures for N. gonorrhoeae, 99% (3237/3271) of men were treated at the initial visit versus 65% (990/1520) of women (P < 0.001). Among patients with positive chlamydial cultures, 87% (344/387) of men and 45% (518/1152) of women received appropriate treatment for their infection at the initial visit (P < 0.001). Thus, use of screening cultures identified 12% and 44% of all patients with gonorrhea and chlamydial infection, respectively, who would not otherwise have been identified as infected (Table 1). The proportion of both gonococcal and chlamydial cultures detected by screening of women substantially exceeded the results of screening men.
The treatment outcomes of patients with positive screening cultures for gonorrhea (34 men, 530 women) and chlamydial infection (43 men, 634 women) are shown in Table 2. Overall, 20% of patients with positive screening cultures for either infection did not return to the clinic for treatment within 30 days of initial presentation. Among those who did return, 30% did so more than 2 weeks after their initial visit. Although significantly more women with gonorrhea or chlamydial infection were detected using screening cultures, men were significantly less likely to return to clinic for treatment of positive screening cultures (P < 0.001). Return rates for therapy did not differ significantly when stratified with respect to age or etiology of infection. Suboptimal therapy for gonorrhea (doxycycline alone) was given at the time of the initial visit for N. gonorrhoeae to 14 of 34 (41%) of men and 85 of 530 (16%) of women with positive screening cultures. Among those patients with gonorrhea who had received doxycycline therapy at the time of initial clinic attendance, return rates for additional treatment were 29% (4/14) and 89% (76/85) for men and women, respectively.
The mission of public health clinical services for the control of STDs has traditionally been two-pronged: provision of immediate antimicrobial therapy for individuals known to be infected or at high epidemiologic risk for infection (e.g., sexual contacts to a known infected case) and screening to uncover asymptomatic but transmissible disease. Although gonorrhea screening has been practiced regularly in STD clinics since the 1970s,6 only recent prioritization and increases in dedicated federal funding for chlamydial control has allowed increased screening for this infection. In our own clinic, despite the fact that we are unable to provide chlamydial testing for all patients, we found more chlamydial infections by screening than gonorrhea. The high yield of C. trachomatis screening is likely the result of this organism's tendency to cause asymptomatic or only mildly symptomatic infection,7,8 as well as the high background prevalence of chlamydial infection in an area where screening has not been regularly practiced in the past.9,10 Despite the high yield of screening in STD clinics, positive screening tests do not guarantee treatment. Evaluation of ways to optimize the numbers of patients with positive screening tests who receive treatment would appear to be an appropriate target for future intervention. Failure to treat the infected individual negates the worth of the screening activity.
In our study, 20% of individuals with positive screening cultures did not return to the clinic within 30 days for treatment. Further, of those who did return, 30% did so only after 14 days. These data appear to confirm earlier observations from Baltimore, where only 26% of women with positive chlamydial tests attending STD clinics returned for therapy.1 In addition, our study suggests that missed treatment opportunities for individuals with positive screening tests are relatively common among men as well as women, and for individuals with gonorrhea as well as chlamydial infection. Our study was not designed to answer questions relating to the infected individual's continuation of sexual activity or development of medical complications. However, untreated asymptomatic individuals are likely to remain sexually active and thus act as continued transmitters of disease, and it has been previously shown that untreated women in particular are at risk for development of upper tract complications such as pelvic inflammatory disease.1,11
Anecdotally, it is widely appreciated that ensuring effective follow-up of patients attending STD clinics is challenging. Nonetheless, because of the large numbers of cases detected and the fact that most of those are successfully treated, we do not advocate elimination of screening programs in STD clinics. Rather, programs must first evaluate the extent of the problem, attempt to remove barriers to patient compliance, and work to find ways to motivate the patient to access test results so that they may receive therapy in a timely fashion. Potential barriers to patient compliance in STD clinics may include lack of understanding of clinic procedures. It is essential that patients have a complete understanding of what they were tested for and why they must take responsibility for obtaining those results. Education and motivational techniques have been found by some to enhance compliance among attendees of public health clinics, and should not be dismissed.12–14 Video presentations in waiting rooms that traditionally have presented facts regarding signs and symptoms of STDs could be augmented with information regarding issues of compliance. Although intuitively it would seem that making results available as early as possible might enhance compliance, it is of interest that some patients are unwilling to wait an additional 30 minutes for results of on-site testing.1 It may be necessary to follow the model advanced by tuberculosis programs in which outreach personnel deliver single-dose therapy directly to the infected patient.
Finally, difficulties in ensuring treatment for STDs detected by screening may be a greater problem for clients receiving care from sites such as STD clinics and emergency rooms than for other sites. In a recent review of patients with positive chlamydial cultures obtained at a major university hospital emergency room, 68% received no treatment at the time of evaluation. Of patients with positive screening cultures, no follow-up or notification could be documented in 44% (Ken Waites, MD, personal communication). In contrast, follow-up of positive screening tests for STD may be less difficult for patients seen in primary care settings such as private physicians' offices or family planning clinics where ongoing longitudinal care of the patient has been established.
In summary, although the yield of screening cultures for gonorrhea and chlamydial infection is high in the STD clinic setting, a substantial number of patients identified as infected by this mechanism fail to return for therapy or do so after a relatively lengthy period of time. These data have important implications for disease control efforts. Interventions to ensure that patients screened for STDs can be appraised of their results in a timely fashion may contribute to efforts to control STDs.
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