Acceptance of HIV Screening
Among those offered routine HIV screening, 2486 (59.7%) accepted and 1701 (40.3%) declined to be tested. Individuals who declined to be tested for HIV were more likely to be older (P < 0.001), to be Asian (P = 0.01), and to live outside the tristate area (P < 0.001) than individuals who agreed to be tested. Multivariate analyses revealed that older age groups were significantly less likely to agree to be tested for HIV compared with individuals <25 years old (odds ratio [OR] for those aged 26 to 35 years = 0.7, 95% confidence interval [CI]: 0.6 to 0.9; OR for those aged ≥36 years = 0.6, 95% CI: 0.5 to 0.7). African Americans were marginally more likely to accept HIV screening (OR = 1.15, 95% CI: 0.99 to 1.32) than whites, whereas Asians were significantly less likely to accept screening compared with whites (OR = 0.52, 95% CI: 0.33 to 0.86). Adjusting for race, age, and gender, local residents were significantly more likely to accept screening compared with individuals from outside the tristate area (OR = 1.46, 95% CI: 1.15 to 1.84).
Preliminary Positive HIV Screens
All patients who had a preliminary positive test result in the ED received their results. As detailed in Table 2, 26 patients (1.1%) had a positive preliminary HIV screen in the ED. Patients who had a preliminary positive test result for HIV were significantly more likely to be male (1.7% vs. 0.6% for female; P = 0.007) and African American (1.9% vs. 0.3% for white; P = 0.001). After adjusting for age and residence, African Americans were still significantly more likely than whites to have a preliminary positive test result (adjusted odds ratio [AOR] = 8.9, 95% CI: 2.5 to 32.0), whereas female patients were less likely to test positive (AOR = 0.3, 95% CI: 0.1 to 0.8). Among the individuals testing positive for HIV, 13 (50.0%) could be reached for follow-up; there were 4 confirmed false-positive test results and 9 (69.2%) patients who reported a positive Western blot test result.
The costs associated with this model of an ED HIV screening protocol reflect the costs of dedicated screeners and the costs of the screening kits themselves. The test kits were provided to the ED through the District of Columbia's Department of Health, and the screeners were provided by the Department of Emergency Medicine. Assuming a cost of $12 per test kit and $7.50 per hour for the staff, the total added expense for the initial 12-week program (providing 156 hours per week of staffing) was approximately $44,000. This reflects a cost per preliminary positive test result of approximately $1700 and a cost of $4900 per confirmed case of HIV infection.
This is the first program to report the characteristics of a routine opt-out ED HIV screening program that does not require written informed consent. We found that almost 60% of the patients who were eligible for screening agreed to be tested for HIV in the ED. The preliminary HIV-positive rate was 1.1%, but because the ED was not equipped to conduct the confirmatory Western blot test, most preliminarily positive patients were referred to a local free clinic for confirmatory testing. A considerable number of patients were lost to follow-up. EDs across the nation are the most likely source of medical services for indigent and low-income populations,6 and these populations are disproportionately affected by HIV infection.7-9 Because of this, offering HIV screening to all patients in the ED is likely to reach large numbers of patients who may be infected with HIV and who otherwise would never be screened.
Washington, DC has one of the highest AIDS case prevalence rates in the United States,10 and our results suggest that ED HIV screening in this high prevalence area is well accepted by patients. The cost per case detected is low; for example, nucleic acid amplification has been used for early detection of HIV infection at a cost of >$17,000 per index case identified.11 Several areas of concern were identified, however.
Linkage to Care
HIV screening cannot be regarded as an end in itself. The success of a screening program should be measured not only by how many patients agree to be tested but, more importantly, by how many of those found to be positive are linked to long-term care. Of the 9 patients who we were able to confirm as being HIV positive, 8 were seen by an infectious disease specialist and the ninth patient was given 2 appointments at an HIV clinic that he failed to keep. Although these numbers are small and need to be replicated, they demonstrate that patients can be successfully linked to care if accurate follow-up information is available. Our program also demonstrated a large number of patients (13 of 26) who were lost to follow-up after a positive HIV screening test result, however. Vigorous efforts were made to contact these patients by means of telephone or registered mail; however, despite this, they could not be traced. In an effort to reduce the number of patients with a preliminary positive result who are lost to follow-up, we have made several modifications to our protocol. Telephone numbers and contact information of all patients with a preliminary positive screen are reviewed and verified together with the patient, and all patients are now offered a confirmatory Western blot test while still in the ED. When the screening program first began, the number of patients who would have a preliminary positive test result was not known. Further, there was no supporting ED infrastructure to accommodate the possible large numbers of Western blot test results that would need to be communicated back to the patients. As a result, the ED management initially required patients who had a preliminary positive test result to obtain a confirmatory test at a later time in a setting to be decided by the patient. Once it became clear that only 2 or 3 patients each week required a confirmatory Western blot, however, a new policy was introduced that allowed a Western blot to be drawn immediately. One ED physician undertook the responsibility for communicating this result to the patient. A second change was the protocol of contacting a physician from the Division of Infectious Diseases while the patient is in the ED. This physician, who is usually able to see the patient briefly while in the ED or to speak with the patient by telephone, makes arrangements with the patient for a clinic appointment, usually within 24 hours. We are currently studying the effects of these protocol modifications in reducing the number of patients who are lost to follow-up.
The rapid HIV screening test has never been advertised as other than a screening tool. The test manufacturers and the CDC have made it clear that a preliminary positive test result should be followed by a confirmatory blood test before making a definitive diagnosis of HIV infection. In a prior study of the OraQuick test, it was reported as being 99.8% specific.12 Assuming that all the negative test results were true-negative results, the ED performance of the OraQuick test demonstrated a specificity of 99.8% and a positive predictive value of 69%. The false-positive rate in our program is not unexpected when studying a population in an ED, especially when considering that known HIV-infected individuals were not studied. These findings emphasize the need for patients to understand that the result is only preliminary and that confirmatory studies are absolutely necessary before the diagnosis can be established. When evaluating this false-positive rate, it should be compared with other tests used in the early detection of HIV infection. For example, in a study of nucleic acid amplification for the early detection of acute HIV infection, 2 patients among a group of 25 RNA-positive patients were found to have a false-positive result.11 We have changed our protocol to require that all tests with a weakly positive result be repeated with a specimen of whole blood, and we are currently collecting data on the outcomes.
Although the CDC recommends that routine opt-out HIV testing require no special written consent or pretest counseling, at least 14 states require either or both of these. The clinical program described herein required neither written inform consent nor pretest counseling, and under these conditions, the acceptance rate was 60%. Nevertheless, it must be noted that during the period of this program, the District of Columbia Department of Health sponsored an advertising campaign emphasizing the need for everyone to be have an HIV test. It is certainly possible that the acceptance rate could be considerably lower in states or cities that require other steps such as written informed consent or in which there was no HIV testing campaign. A study done in Chicago, which used rapid HIV testing utilizing whole blood, had an almost identical acceptance rate of 59%, however.13 In contrast to our protocol, that study did require written informed consent before HIV screening. The acceptance rate was 64% in an ED-based program that provided targeted HIV testing in Ohio.14 The different study protocols and staffing patterns used in these other programs make comparisons somewhat difficult; however, together with our results, these findings suggest that a large number of patients are willing to be screened for HIV infection while in the ED. Furthermore, when considering the acceptance rate in our clinical program, it must be recognized that none of the patients who agreed to be screened for HIV had arrived at the ED requesting this test. Given these facts, we view the acceptance rate of 60% as encouraging. Further studies are needed to determine the reasons why 40% of patients decline to be tested, and further modifications to the program should aim to increase the acceptance of routine testing among ED patients.
This clinical program tested approximately 31% of the patients who were in the target test range. Those patients not offered testing include those who were already known to be HIV-positive, those whose urgent medical needs took priority, those with an abnormal mental status or a language barrier, and those who were otherwise eligible but were missed by the screening personnel (although the proportions were not recorded). To screen a higher percentage of eligible patients, more staff would be needed, and this would add to the costs of the program.
Costs and Sustainability
Routine HIV testing has repeatedly been shown to be cost-effective, even in low-prevalence settings.15-17 This program is the first to demonstrate that compared with other methods of early detection, routine opt-out screening in the ED is also cost-effective. The low costs of <$5000 per confirmed HIV-positive patient identified demonstrate support for earlier theoretic models that provided an economic evaluation of prior CDC HIV screening guidelines. For example the model by Walensky et al16 demonstrated that routine HIV screening had a cost-effectiveness ratio of $35,400 to 64,500 per quality-adjusted life-year (QALY) gained. These numbers compare favorably with cost-effectiveness estimates for other routine screening programs for diseases, such as type II diabetes ($70,000 per QALY gained), hypertension ($80,400 per QALY gained), and colon cancer ($57,700 per QALY gained). Despite the clear cost-effectiveness of ED HIV screening, programs such as the one we describe here, they are not going to be sustainable unless EDs are able to recover the full costs of screening, including the costs of the test kits and extra personnel. This issue has already been identified by the CDC as being of major concern, (Bernard Branson, personal communication, December 2006), and the future of routine ED HIV screening should ultimately depend on reimbursement rates negotiated between hospitals and payers. Until then, it is unlikely that individual EDs are going to be able to bear the extra costs of providing routine HIV screening for their patients, however successful these programs may be in identifying new cases of HIV infection.
An ED-based opt-out HIV screening program in accordance with the 2006 CDC guidelines is feasible, cost-effective, and well received by patients. Emphasis needs to be placed on increasing the number of patients who agree to be screened and ensuring continuity of care for patients with a positive test result. Before wider dissemination of these screening programs, hospital managers need to obtain a secure method of funding and overcome ED service delivery challenges.
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Keywords:© 2007 Lippincott Williams & Wilkins, Inc.
epidemiology; HIV screening; public health