Risk of human immunodeficiency virus infection for emergency department workers

The Journal

Pergamon

of Emergency

Medicine, Vol 12, No 6, pp 737-744, 1994 Copyright 0 1994 Elsevier Science Ltd Printed in the USA. All rights reserved 0736-4679194 $6.00 + .OO

0736~4679(94)ooo75-1

al Contributions

RISK OF HUMAN IMMUNODEFICIENCY VIRUS INFECTION FOR EMERGENCYDEPARTMENTWORKERS Gabriella

De

Carli,

Vincenzo Pure, MD, * Nancy J. Binkin, MD,+ Giuseppe Ippolito, Italian Study Group on Occupational Risk of HIV Infection

MD, *

“Coordinating Reprint

Address:

Center: Unita’ tCDC-Epidemiology Dr. Giuseppe Ippolito,

Operativa

AIDS, L. Spallanzani Hospital, Rome, Program Office, Atlanta, Georgia Unita’ Operativa AIDS, Ospedaie L. Spallanzani, 292-00149 Rome, Italy

0 Abstract-To evaluate the risk of human immunodeficiency vims (HIV ) exposure among emergency department workers (EDWs) and their ability to identify HIV-infected patients, a seroprevalence study was performed in March 1991 in the emergency departments (EDs) of six Italian urban hospitals. At each visit, patients aged 18-65 years were asked to undergo fingerstick blood sampling for anonymous, unlinked HIV testing performed on blood adsorbed filter paper collection cards. Demographic characteristics, known or suspected HIV risk factors, and occupational exposures reported by the EDWs during the patient’s visit were recorded. On 9,457 consecutive visits, 9,005 samples (95%) were tested and 65 (0.7%) were HIV positive. ED staff failed to identlfy 59% of HIV-infected patients. The rate of occupatiomtl exposures was 0.13/100 visits. As it is impossible to predict the HIV status of patients attending EDs, adherence to universal precautions and the development of safer devices should be utilized to minimize the risk of blood-borne infections in EDWs. 0 Keywords - accidents; emergency service; HIV prevalence; occupational; risk

MD,’

and the

Italy; Via Portuense,

contacts to which they are exposed during their careers (3-6), the urgent nature of their work (which may provide little opportunity for taking appropriate precautions) (7), and the higher risk status of the patient population they treat (8-10). Several studies have been conducted in the United States (U.S.) to assessthe prevalence of blood-borne infection in emergency department (ED ) patients. Almost all have found prevalences of hepatitis B virus (HBV), hepatitis C virus (HCV), human T lymphotropic viruses (HTLV I/II), and human immunodeficiency virus (HIV) infection higher than those observed in the general population and in blood donors (8,10-14). Moreover, the prevalence of HIV infection among ED patients appears to be increasing in the U.S. (7), as is the proportion of patients cared for in EDs with the acquired immunodeficiency syndrome (AIDS) (7,15,16). Numerous studies have assessed the impact of HIV infection in Western Europe, with a wide range of prevalence rates and a significant disparity in levels and distribution between different geographical areas, within the same area, and among different population groups. This reflects different periods and routes of HIV spread (17). In the northern countries (e.g. France, Switzerland, Sweden, United Kingdom, etc.), the disease has become more of a

sero-

INTRODUCTION

Emergency department workers (EDWs) are considered to be at high risk for acquiring blood-borne infections ( 1,2) because of the high number of blood

Original Contributions is coordinated by John A. Marx, MD, of Carolinas Medical Center, Charlotte, North Carolina RECEIVED: 1 July 1993; FINAL SUBMISSIONRECEIVED: 15 December 1993; ACCEPTED: 7 January 1994 737

G. De Carli et al.

disease of intravenous drug users (IVDU) than of homosexual men, as it has in the U.S. Differently, in southern countries (e.g. Italy, Spain, Greece), HIV infection has spread widely among IVDU since the beginning of the epidemic. In Italy, up to September 1993, a total of 18,832 AIDS cases have been reported, with a male to female ratio of 4 : 1. The disease is seen almost exclusively in IVDU, who account for 66% of male and 68% of female adult AIDS cases (18), although a low but constant increase of female AIDS cases is being observed due to the heterosexual route (15.7% in 1989, 19.1% in 1991, 23.3% up to September 1993) (18-20). In Italy, prevalence rates of HIV infection in selected groups have been assessed that range from 6% to 50% in IVDU (21), while among sexually transmitted disease (STD) clinic clients, they were 1.1% and 1.5070, respectively, in heterosexual males and females and 16% in homosexual males (22). HIV prevalence was 0.16% among newborns in a nationwide survey (23) and 0.014% in blood donors (24). Little is known about the risk of blood exposure and HIV prevalence among patients in the EDs of European countries. Two studies conducted in Spain showed HIV prevalence to be 1.38% among overall patients in an ED in Valladolid, while in Barcelona, 8.4% of ED patients were infected with HIV but 1.1% were unrecognized (25,26). The ED utilization in Europe may differ from that in the U.S. because of the greater accessibility of routine health care by persons of limited financial means and differences in the composition of the HIV-infected population that may affect the frequency and the pattern of ED use. To examine the risk of occupational exposure to HIV-infected patients in EDs, as well as the frequency with which HIV-infected patients are correctly identified by EDWs, a multicenter study involving six Italian EDs was conducted.

PATIENTS

AND METHODS

Setting The study was conducted at six full-service, busy EDs located in public acute-care hospitals serving the general population of four metropolitan areas and the local community of two suburban areas. Four of the hospitals (hospitals A, B, C, and D) are large hospitals with a wide variety of clinical departments (including infectious disease departments and drug addiction treatment services); one of them (hospital D) is a teaching hospital. The remaining two (hospitals

E and F) have not only the main departments (medicine, surgery, obstetrics and gynecology, emergency medicine), but they also have drug addiction treatment services. The characteristics of the hospitals are shown in Table 1. All of the hospitals participate in an ongoing multicenter study on occupational risk of HIV infection that was started in 1986 (27), so that in these hospitals several training programs have been performed on this topic and, according to the guidelines issued by the Italian Ministry of Health in 1989 (28), a policy of Universal Precautions is in place.

StudyDesign Over a l-month period between March and April 1991, all patients seen in the EDs who were between 18 and 65 years old were asked to undergo fingerstick blood sampling for anonymous and unlinked HIV testing. The gynecology and pediatric EDs were not included in this study. Patients were informed about the purposes of the study and of the possibility of obtaining free confidential testing and pre- and posttest counseling at local sites. At each visit, patients were interviewed by a nurse responsible for data collection, regardless of whether the patient consented to be tested. The following data were recorded on a standard form: sex; age; work shift (7.00 a.m.-2.00 p.m., 2.00-10.00 p.m., 10.00 p.m.-7.00 a.m.); presence of active bleeding (e.g. posing a risk of contamination to EDWs); presence of trauma; and presence and type of risk factors for HIV infection, both self-reported by the patient and suspected by the staff members. At each patient’s discharge, the nurse completed the form, reporting the occurrence of occupational exposures to the patient’s blood during the visit (needlestick, cut, mucous membrane contamination, nonintact skin contamination). Risk factors were categorized as known when a complete medical history was available from existing records, when HIV infection or high-risk behaviors were reported during history taking, or on the basis of clinical presentation (e.g. heroin overdose). Risk was recorded as suspected when the patient denied any high-risk behavior but, for whatever reason, the EDWs felt the patient to be at risk for HIV infection. The “suspicion” of risk was not defined in the study protocol to have a real picture of the EDWs’ attitude and perception, and no attempt was made to obtain a precise definition of “how and why”

739

HIV Risk for Emergency Workers Table 1. Chrrscteristics

of the P8rtiClpatiIIg

Hospitals

Total Admissions in 1990&(n)

Patient Visits Recorded in ED in 1990b (n)

Hospital

Total Beds (n)

A B C D E F

1,544 1,170 1,043 2,125 728 260

44,327 24,516 31,867 61,008 18,731 9,203

109,361 39,647 63,696 92,009 29,061 41,000

Total

6,868

189,672

394,864

‘Patient’s duration of stav lonaer than 1 day. blncluding gynecology at+d pediatric ED

the EDW felt the patient was at risk for HIV infection. Finally, risk was defined as not identified if the patient denied at interview any high-risk behavior and the EDWs did not consider the patient to be at risk for HIV infection. The following risk behavior categories were considered: intravenous drug use, homosexuality, sexual intercourse with high-risk or HIV-positive partners, blood or blood product transfusion before 1986. Since the risk of exposure to HIV-infected patients for EDWs depends more on the number of contacts than on the absolute number of HIV-infected patients, no attempt was made to exclude repeat testing of patients who visited the EDs more than once during the study period, and patients with known HIV infection or with HIV-related illness were not excluded from the study. Therefore, prevalences have been calculated based on the number of visits rather than on the number of patients. Specimen Collection and Test Protocol Four drops of whole blood were adsorbed on filter paper collection cards (S&S, grade 2992). After air drying, the specimens were mailed to a single centralized laboratory where they were eluted, as previously described (29,30), and tested. Briefly, 3-mm disks were punched from four different patient blood collection cards, pooled in a test tube, and eluted and tested at once by a commercial enzyme immunoassay (ELAVIA I - Diagnostic Pasteur, France) employing the standard assay protocol. For pools that were either positive or borderline, the four samples were retested individually, Specimens consistently reactive were subsequently analyzed by Western blot (New LAV BLOT I - Diagnostic Pasteur, France). Results of the Western blot test were interpreted

according to the proposed World Health Organization (WHO) criteria (3 1); Western blot confirmation of a positive enzyme immunoassay (EIA) test was considered to be evidence of HIV infection. Validation of Assays Technical feasibility and validity of HIV ELISA testing of the eluate obtained from four pooled dried blood spots was evaluated before beginning the study through parallel testing on serum and whole blood adsorbed on filter paper, A panel of 88 pools was tested, each containing four 3-mm paper spots. Of the four spots in each of the pools, three contained blood from a single unit that had been certified to be HIV negative by the central laboratory of the Italian Red Cross in Rome. The fourth spot added to complete each pool was taken from blood samples that tested positive (22 samples), negative (56 samples), or indeterminate (10 samples) in Western blot testing performed at the Department of Virology of the Italian National Institute of Health-World Health Organization Reference Center for AIDS. Eluate from each pool of four disks was tested according to the study protocol. The technicians performing the test were unaware of the contents of each pool and the ratio of positive, negative, and indeterminate specimens. All of the 22 positive samples, the 56 negative samples, and 8 out of the IO indeterminate samples were correctly identified. The remaining two indeterminate samples, which were weakly reactive only for one gag protein (~18 or p24), were not identified testing the pools by EIA and were classified as negative. Statistical Analysis Simple comparisons were done using the chi-square test for proportions, Fisher-exact test, or the Stu-

G. De Carli et al.

740

dent’s t-test. Prevalence odds ratios and 95% confidence intervals (CIs) were calculated using Epi Info statistical package (32).

and all were confirmed with Western blot (0.72%). Seroprevalence rates varied from 0.3% for hospital F to 1.1% for hospital C, with a mean value of 0.6%. Prevalence was 0.79% among males and 0.61% among females. Mean age of seropositive patients was 31 years (median, 30 years; SD, 10.2 years). The highest prevalences were observed among patients aged 30-34 years (2.47%), 25-29 years (1.34%), and 20-24 years (0.85% ). Seropositivity rates among patients seen during the night shift were more than four-fold higher than among those seen during the day and three-fold higher than those seen during the afternoon shift (p < 0.01 for both comparisons). No differences in seropositivity rates were observed among those with and those without active bleeding or trauma (0.63% vs. 0.74%, respectively, in both comparisons). In a total of 120 visits (1.33%), patients reported themselves as engaging in high-risk behaviors (two of whom acknowledged previous positive HIV test results), while the EDWs suspected the presence of risk factors in an additional 246 (2.73%). Among those who reported themselves as being at risk, 16.7% (20/120) were seropositive. For the group suspected by the EDWs as being at risk, the corre-

RESULTS During the study period, there were a total of 9,457 ED visits among patients fulfilling the enrollment criteria. Most patients agreed to undergo HIV testing (95.2%; n = 9,005); information on patient characteristics was obtained from the remaining 4.8% (n = 452). Patients who declined testing were significantly younger (median, 30 years; mean, 34 years; SD, 12.5 years) than those who agreed to be tested (median, 38 years; mean, 39 years; SD, 14.3 years) (p < 0.001). No statistically significant differences were observed between the two groups with respect to sex, presence or suspicion of risk factors for HIV infection, ED shift, or presence of bleeding or trauma, as shown in Table 2. Table 3 summarizes the demographic and medical characteristics of patients who were tested and their serostatus. Of the 9,005 blood samples tested for anti-HIV antibodies, 65 were positive by ELAVIA

Table 2. Characteristics of 9,457 Patient Visits in Six Emergency Departments During March 1991 Not Tested

Tested

Gender Female Male Age (years) 18-19 20-24 25-29 30-34 35-39 40-49 50-59 60-65 Risk factor infection

for

P Value

n

%

n

%

3,611 5,394

40.1 59.9

167 285

63.1

0.19

573 1.287 1:270 891 759 1,746 1,452 1,027

6.4 14.3 14.1 9.9 8.4 19.4 18.1 11.4

36 101 89 57 44 78 51 18

8.0 22.3 15.3 12.6 9.7 16.8 11.3 4.0

< 0.001

120 246 8,639

1.3 2.7 95.9

7 19 426

1.5 4.2 94.2

0.18

4,098 3,861 1,046

45.5 42.9 11.6

197 204 51

43.6 45.1 11.3

0.63

1,430 7,575

15.9 84.1

84 388

15.2 85.8

0.36

1,271 7,734

14.1 85.9

51 401

11.3 88.7

0.10

36.9

HIV

Suspected Not identified Shift of admission 7 a.m.-Z p.m. 2 p.m.-10 p.m. 10 p.m.-7 a.m. Presence of bleeding Yes No Trauma Yes No

741

HIV Risk for Emergency Workers Table 3. Characteristics of 9,005 Patients Seen in Six Emergency Who Consented To Be Tested for HIV

During

March 1991 -

Prevalence

Seropositive Persons

Gender Female Male Age (years) 18-19 20-24 25-29 30-34 35-39 40-49 50-59 60-65 Risk factor for HIV infection Known Suspected Not identified Shift of admission 7 a.m.-2 p.m. 2 p.m.-10 p.m. 10 p.m.-7 a.m. Presence of bleeding Yes No Trauma Yes No

Depattments

95%

Confidence Interval

Visits VJ)

(n)

o/o

Odds Ratio

3,611 5,394

22 43

0.61 0.79

0.76 1

0.44-l

573 1,287 1,270 891 759 1,746 1,452 1,027

1 11 17 22 4 4 3 3

0.17 0.85 1.34 2.47 0.53 0.23 0.21 0.29

0.60 2.94 4.63 8.64 1.81 0.78 0.71 1

0.02-6.40 0.76-l 3.30 1.28-19.90 2.45-36.34 0.34-10.17 0.15-4.40 0.1 l-4.37

120 246 8,839

20

45.27 6.63 1

24.44-83.40 2.87-l 5.67


3:

16.70 2.85 0.44

4,098 3,861 1,048

17 29 19

0.41 0.75 1.82

1 1.82 4.44

0.96-3.45 2.20-8.98


1,430 7,575

9 56

0.63 0.74

0.85 1

0.39-l

.78

1,271 7,734

8 57

0.63 0.74

0.85 1

0.39-l

.86

sponding value was 2.8% (7/246). By contrast, among the remaining 8,639 admissions for whom no risk factors were identified, 38 (0.4%) were seropositive. A total of 13 accidental exposures of EDWs were reported (0.13/100 visits), 9 of which were cuts. Of the remaining 4, 2 were puncture injuries, 1 was contamination of nonintact skin, and 1 was contamination of mucous membranes. All of the cuts and one of the needlestick injuries occurred while treating patients who had sustained trauma and were actively bleeding. The rate of occupational exposures was 0.75% ( lO/ 1322) when EDWs were treating trauma patients with bleeding, 0.03% (3/7956) when treating nonbleeding, nontrauma patients (relative risk = 20.07, 95% CI = 5.5-72.8; p < 0.001, Fisher exact test), while no exposures occurred while treating 176 bleeding, nontrauma patients (0070, 95% CI = o-2.07). The rate of exposures per visit was slightly higher at night (0.18%) than during the day and afternoon shifts (0.11% and 0.15070, respectively). Of the 13 EDW exposures, none was to an HIV positive source or to a patient with known or suspected risk factors.

P Value

-

.31

0.01
DISCUSSION We found that 0.72% of visits in the participating EDs involved HIV-infected patients, thus representing a potential hazard for EDWs of acquiring HIV infection after an occupational exposure. The wide range of prevalence observed in the EDs reflects the variation in distribution of the epidemic between different geographical areas. A similar disparity was found in the U.S. (14) as well as in the abovementioned Spanish studies (25,26). Our rate is 5 times higher than the estimated HIV prevalence of about 0.15% in the Italian general population (33). This difference is consistent with what has been observed by other authors; Kelen and coworkers (7) found the prevalence in ED patients to be 10 times higher than that estimated in the general population of Baltimore (6.0% vs. 0.6%, respectively) (34). A similar difference, reflecting the highrisk status of the patient population attending EDs, has been observed by other authors in the U.S., with prevalences varying from 0.5% to 7% in different studies (8,10,13,14) compared to a mean prevalence of 0.48% in the general population (35). When we examined predictors of seropositivity,

742

no significant differences in HIV seroprevalence rates were observed with respect to sex, presence of active bleeding, or presence of trauma. Three factors were found to be somewhat correlated with HIV infection in patients attending the EDs (Table 3): (1) patient age between 20 and 34 years, (2) patient treatment during the night shift, and (3) EDWs’ knowledge or suspicion of patients’ risk factors. These findings could be explained at least in part by a higher attendance of IVDU to EDs due to the inaccessibility of drug addiction treatment services at night and by their lifestyle, which increases their risk of accidents. In Europe, increasing attendance of IVDU for problems related both to HIV infection and to the abuse of intravenous drugs has been noted (36-39). In our study, IVDU, who represent 64% of AIDS cases in Italy, accounted for 55% of subjects who agreed to be tested and for whom a risk factor was known (66/120) and for 22% (54/246) of subjects in whom a high-risk behavior was suspected by the EDW. Finally, known or suspected IVDU accounted for 28% of subjects who tested positive for HIV. This is in agreement with a mean prevalence of anti-HIV of 31% in Italian IVDU (33). However, none of the predictors was a sensitive indicator. Indeed, 23% of the HIV-infected patients were less than 20 or more than 34 years of age, and 71% were seen during the day or afternoon shift. The correct identification of patients with HIV infection through risk assessment was also low; even though the relative risk of being infected when a risk factor had been known or suspected was 16.8% (95% CI = 10.4-27.2), 58.5% of infected patients were not recognized at the moment of the visit. The observed rate of seropositivity in our study may be an underestimate, as participation was voluntary, and patients who decline to be tested may be more likely to be infected than those who consent (40-42). The mean age of patients declining testing was significantly lower than that of those consenting (P < 0.01) and was similar to the mean age of patients who tested positive (P = 0.56). These two facts suggest that the overall seroprevalence among patients attending EDs could actually be higher than that observed, mostly due to IVDU who account for the highest proportion of subjects with HIV infection in the younger age groups. The testing method we used should not have affected the results. Indeed, pooling of sera is recommended as a costeffective and sensitive method to monitor HIV prevalence through blinded serosurveys in low prevalence areas (43-45). Recovery of antibodies to HIV from whole blood samples spotted on filter paper after

G. De Carli et al.

elution is comparable to that obtained from serum specimens (46,47). Finally, in our validation of assays, we found a high sensitivity of tests performed on pooled eluates . The collection of whole blood on filter paper for antibody assay has unique advantages over the use of serum samples; materials required for obtaining the specimens are minimal, and the filter cards take up little space, cannot be broken or split, can be stored at room temperature for several weeks, and can be mailed easily (46). Additionally, using lancets, rather than hollow needles, to collect specimens may minimize the risk of stick injuries and of blood-borne occupational infection, and filter cards are safer to handle and process in the laboratory than sera (47). Moreover, our low refusal rate suggests that a fingerprick may be more acceptable than a venipuncture for anonymous voluntary testing, reducing the bias due to refusal (41). Also, our low refusal rate could be explained by other incentives such as the possibility of obtaining free confidential testing and pre- and posttest counseling at local sites. To investigate prevalence rates, other authors have used residual sera acquired for clinical laboratory testing to conduct nonvoluntary, anonymous, unlinked studies to avoid participation bias. However, in these studies, up to 45% of patients attending EDs have been lost, since not all patients seen in EDs will have blood drawn, and in many cases no residual sera are available (9). In our study, EDWs reported 13 occupational exposures in 9,457 visits (0.13%), of which 11 were percutaneous injuries. Although not strictly comparable, the rate we observed is not significantly different from the 0.06% rate of parenteral exposures found by Marcus and coworkers in an independent observer study, which used the number of procedures as a denominator (3). Conversely, a rate of 3 percutaneous injuries per 100 procedures during ED resuscitations has been observed among EDWs in critically ill, resuscitated ED patients ( 13). Overall, 10 of 13 exposures reported in our study occurred while EDWs treated actively bleeding patients who had sustained trauma. These data suggest that emergency conditions can influence occupational behaviors (13). Moreover, we observed that all the exposures occurred while treating patients with no acknowledged risk factors. This could suggest differences in EDWs’ attitudes and practices when they perceive a sense of security. A false sense of security could explain the worrying attitude among EDWs reported by Moss and coworkers (48), who observed a very careful sharps management when dealing with patients who were known to be

743

HIV Risk for Emergency Workers

infected with HIV but a rather careless management of other patients even when they were known to be at high risk. The anonymous unlinked design of the study does not allow us to assess the number of patients who visited the EDs more than once during the study period. By linking ED, sex, age, presence and type of risk factors, and test result, we can estimate that less than 1% of patients with known or suspected risk factors could have been seen more than once during the survey. However, this should not represent a limitation in evaluating our results, since unrecognized HIV-infected patients put EDWs most at risk, if the workers do not comply with universal precautions. Universal precautions stress the need for considering every patient as a potential source of blood-borne infections (49). This is even more significant in EDs, where emergency conditions and the lack of time for the staff to put on protective apparel may result in more frequent contact with patients’ blood. The rate of exposure and the impossibility of predicting HIV

status (50) and other blood-borne infections (i.e. HBV, HCV, and HTLV I/II) in patients attending EDs make the need for implementing health care workers’ vaccination against HBV, adherence to universal precautions (8,51), and the use of safety devices and techniques (52) evident.

Acknowledgments-Participants to the Italian Study Group on Occupational Risk of HIV Infection are Aebischer ML, Angeloni U, Costa F-Laboratorio Centrale Croce Rossa Italiana (Rome); Bonazzi L, Guerra L, Rosini G - Ospedale Maggiore (Bologna); Cestrone A, Cusinato T - Ospedale Civile (Cittadella-Padova); Francesconi M, Persia S-Ospedale S. Sebastian0 (Frascati); Orazi D, Marani C, Vaccarino M -0spedale S. Camillo (Rome); Sesti E, 2~110 G, Orefice E-Ospedale S. Filippo Neri (Rome); Tavio M, Corradi MP, Amelio N- Policlinico (Modena). We thank Doriana Torriero for her secretarial support. This work was supported by the Ministry of Health, AIDS project: grants 6202.020 and 7201.23.

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