Article

Validation of an abbreviated version of the Denver HIV Risk Score for prediction of HIV infection in an urban ED

a b s t r a c t

Objective: We sought to evaluate the performance of an abbreviated version of the Denver HIV Risk Score in 2 urban emergency departments (ED) with known high undiagnosed HIV prevalence.

Methods: We performed a secondary analysis of data collected prospectively between November 2005 and December 2009 as part of an ED-based nontargeted rapid HIV testing program from 2 sites. Demographics; HIV testing history; Injection drug use; and select High-risk sexual behaviors, including men who have sex with men, were collected by standardized interview. Information regarding receptive anal intercourse and vaginal intercourse was either not collected or collected inconsistently and was thus omitted from the model to create its abbreviated version.

Results: The study cohort included 15184 patients with 114 (0.75%) newly diagnosed with HIV infection. HIV prevalence was 0.41% (95% confidence interval [CI], 0.21%-0.71%) for those with a score less than 20, 0.29% (95% CI, 0.14%-0.52%) for those with a score of 20 to 29, 0.65% (95% CI, 0.48%-0.87%) for those with a score of 30 to 39, 2.38% (95% CI, 1.68%-3.28%) for those with a score of 40 to 49, and 4.57% (95% CI, 2.09%-8.67%) for those with a score of 50 or higher. External validation resulted in good discrimination (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.71-0.79). The calibration regression slope was 0.92 and its R2 was 0.78.

Conclusions: An abbreviated version of the Denver HIV Risk Score had comparable performance to that reported previously, offering a promising alternative strategy for HIV screening in the ED where limited sexual risk behavior information may be obtainable.

(C) 2014

  1. Introduction

Emergency departments (EDs) are the most common site of missed opportunities to diagnose HIV infection in medical settings [1]. In 2001, the Centers for Disease Control and Prevention (CDC) revised their HIV testing guidelines and specifically highlighted EDs as the primary nontraditional clinical care settings for expanded HIV testing

? Funding: Supported, in part, by an independent scientist award (K02HS107526) from the Agency for Healthcare Research and Quality and an investigator-initiated grant (R01AI106057) from the National Institute of Allergy and Infectious Diseases to

Dr Haukoos.

?? Conflicts of Interest: None declared.

? Meeting: Presented in part at the 2011 Society for Academic Emergency Medicine

Annual Meeting, Boston, MA, June 1 to 5, 2011.

?? Author contributions: JSH and Y-HH conceived and designed the study. JSH and Y-

HH provided statistical advice on study design and Y-HH analyzed the data. Y-HH and JSH interpreted the results and Y-HH drafted the manuscript. RER and JSH contributed substantially to its revision. Y-HH takes responsibility for the manuscript as a whole.

* Corresponding author. Tel.: +1 410 735 6413; fax: +1 410 735 6425.

E-mail address: [email protected] (Y.-H. Hsieh).

[2]. Under those guidelines, the strategy for HIV screening remained the same as that recommended in 1993 [3], with risk-based screening (ie, routinely asking patients about risks for HIV infection and offering confidential voluntary HIV counseling and testing for those at risk) except for those in high HIV/AIDS prevalence areas, where routine screening was recommended. In 2006, the CDC again revised their guidelines, recommending routine nontargeted (non-risk-based) opt- out HIV screening for all patients 13 to 64 years old [4]. Since then, the growing numbers of EDs have developed strategies to adopt HIV screening as part of their routine practice and reported much higher rates of HIV positivity above the CDC threshold of 0.1% in those with systematic testing programs [5]. Yet, most EDs with systematic HIV screening programs still do not use nontargeted approaches, mainly because it is operationally challenging to implement [6,7]. Further- more, it is costly for EDs to implement such Screening programs [8], even with external public and private grant funding support.

Recently, a clinical prediction instrument, called the Denver HIV Risk Score (DHRS), was derived and validated in 2 relatively low HIV prevalent settings in Denver, Colorado, and Cincinnati, Ohio. The purpose of the DHRS was to categorize patients into distinct risk groups

http://dx.doi.org/10.1016/j.ajem.2014.02.043

0735-6757/(C) 2014

with increasing probabilities of HIV infection in an effort to help inform routine HIV screening [9]. In its original form, the DHRS includes the following 8 characteristics: age, sex, race/ethnicity, sex with a male, vaginal intercourse, receptive anal intercourse, injection drug use (IDU), and a past HIV test. Several of these variables may be considered sensitive to both ED patients and providers and thus are not always feasible to collect routinely in busy clinical settings, including EDs. Many were wondering if a modification of DHRS based on local availability of key elements might be applied and perform well in their own ED-based HIV testing programs. Therefore, we sought to evaluate the performance of an abbreviated version of the DHRS that excludes 1 and modifies 2 sexual behavioral variables in an inner-city ED located in a city with known high undiagnosed HIV prevalence.

  1. Materials and methods
    1. Study design

We performed a secondary analysis of data collected prospectively between November 2005 and December 2009 as part of a nontargeted rapid oral fluid HIV screening program from 2 sites: an inner-city ED with 60000 adult visits per year (site A) and an urban ED with 55000 annual visits (site B). The study was approved by the institutional review boards of the institutions.

Setting

The 2 urban EDs are part of a single university health care system located in Baltimore, Maryland. Site A is an inner-city adult ED with 60 000 visits per year, whose population is socioeconomically disadvantaged, with more than 75% African Americans, 15% prior or current injection Drug users, and 11% to 12% HIV seroprevalence (with approximately 2.2% rate of new diagnosis in 2006 and 0.8% in 2009) [7,10]. Site B is an urban adult and pediatric ED with 55000 visits per year, which serves an ethnically and socioeconomically diverse population, with 30% to 35% African Americans and high rates of sexually transmitted infections; overall rates of HIV at that site are not known, but rates of newly diagnosed HIV are approximately 0.3% [11].

Data collection

Demographics (age, sex, race/ethnicity); HIV testing history; IDU; and some sexual risk behaviors, including men who have sex with men, were collected by a standardized interview by HIV screening facilitators as part of the program. Elements in the DHRS explicitly collected using our standardized interview included age, sex, race/ ethnicity, sex with a male, IDU, and HIV testing history. Information regarding receptive anal intercourse and vaginal intercourse, 2 of the sexual practice elements that are parts of the DHRS, was not explicitly collected at our site. Information regarding having sex with men was consistently collected for male or transgender patients throughout the study periods but was not collected for female patients in the early part of study period and was not consistently collected afterwards. HIV testing facilitators interviewed patients, recorded data on standardized data collection instruments, and entered data into a password-protected secure departmental Web site.

Data analysis

The DHRS was retrospectively applied to the deidentified data set (Table 1) [9]. Males, females, or transgender patients who stated having sex with men were assigned a score of +22 for the item “sex with a male”; the remaining subjects were assigned a score of 0. No score of “receptive anal intercourse” and “vaginal intercourse” was assigned to each subject because the information was not collected. Patients were grouped into risk score categories (b 20, 20-29, 30-39,

Table 1

Denver HIV Risk Score and an abbreviated DHRS

Variables

Categories

Original score

Modified scorea

Age

b 22 or N 60 y

0

0

22-25 or 55-60 y

+4

+4

26-32 or 47-54 y

+10

+10

33-46 y

+12

+12

Sex

Female

0

0

Male

+21

+21

Race/ethnicity

Black

+9

+9

Hispanic

+3

+3

White

0

0

Otherb

0

0

Sexual practices

Sex with a man

+22

+22

Vaginal intercourse

-10

NC

Receptive anal intercourse

+8

NC

Injection drug

IDU

+9

+9

practices

HIV testing

Having an HIV test in the past

-4

-4

Abbreviation: NC, not collected in site A and Site B screening program.

a In the modified abbreviated DHRS applying for site A and B, men or transgender who stated having sex with men and all females were assigned a score of 22 for the item “sex with a man”; the remaining subjects were assigned a score of 0. No score of “vaginal intercourse” and “receptive anal intercourse” was assigned to each subject.

b Represents Asian, American or Alaskan Native, Hawaiian, and Pacific Islander.

40-49, >=50), and HIV positivity rate within each group was reported as percentages with 95% confidence intervals (CIs). Calibration of the abbreviated DHRS was assessed by plotting and comparing predicted HIV prevalence to observed HIV prevalence and reported as a slope and R2 of the corresponding linear regression line using the same analytical approach in the original derivation study [9]. Discrimina- tion was assessed by constructing a receiver operating characteristic curve and calculating its area under the curve. Sensitivity analysis was performed by (1) treating all females having sex with a male because the variable “sex with a man” was not consistently collected for female patients (model 1) and (2) removing all 3 sexual questions in the original DHRS (model 2). Statistical analyses were performed using SAS, version 9.3 (SAS Institute, Inc, Cary, NC).

  1. Results

During the study period, 15184 ED patients were tested for HIV infection. Of these, 114 (0.75%) were newly diagnosed with HIV infection. The demographic and risk characteristics related to the

Table 2

Demographics and risk characteristics in 15184 patients of 2 EDs who received a rapid HIV test via ED-based rapid HIV screening program

Characteristics Categories n (%)

Age b 22 y 1614 (10.6)

22-25 y 1712 (11.3)

26-32 y 2354 (15.5)

33-46 y 4720 (31.1)

47-54 y 2837 (18.7)

55-60 y 1424 (9.4)

61-64 y 523 (3.4)

Sex Female 8160 (53.7)

Male 7017 (46.2)

Transgender 7 (0.1)

Race/Ethnicity Black 8844 (58.2)

Hispanic 449 (3.0)

White 5331 (35.1)

Othera 560 (3.7)

Sexual practices Men who have sex with men 210 (3.0)+ Injection drug practices IDU 1085 (7.2) HIV testing Having an HIV test in the past 9353 (61.6)

a Represents Asian, American or Alaskan Native, Hawaiian, Pacific Islander, race not specified, race unknown, or declined.

+ Total number of male patients as the denominator.

DHRS are summarized in Table 2. Most patients were young adults younger than 40 years (50.7%), female (53.7%), African American (58.3%), and having been previously tested for HIV infection (61.6%). The median abbreviated DHRS was 31 (interquartile range, 22-37; range, -4 to 73). HIV prevalence was 0.41% (12/2961; 95% CI, 0.21%-

0.71%) for those with a score less than 20, 0.29% (10/3420; 95% CI,

0.14%-0.52%) for those with a score of 20 to 29, 0.65% (46/7052; 95%

CI, 0.48%-0.87%) for those with a score of 30 to 39, 2.38% (37/1554,

95% CI, 1.68%-3.28%) for those with a score of 40 to 49, and 4.57% (9/188; 95% CI, 2.09%-8.67%) for those with a score of 50 or higher (Fig. 1A). The calibration regression slope was 0.92 and its R2 was

0.78 (Fig. 2A), whereas the area under the receiver operating characteristic curve was 0.70 (95% CI, 0.65-0.75) (Fig. 3A).

In the sensitivity analysis, for model 1, we found that the median abbreviated DHRS was 33 (interquartile range, 29-38; range, 17-73). HIV prevalence was 0.0% (0/269; 95% CI, 0%-1.20%) for those with a score less than 20, 0.13% (5/3830; 95% CI, 0.04%-0.31%) for those with a score of 20 to 29, 0.59% (52/8812; 95% CI, 0.44%-0.77%) for those with a score of 30 to 39, 2.33% (48/2063; 95% CI, 1.72%-3.09%) for those with a score of 40 to 49, and 4.29% (9/210; 95% CI, 1.96%-8.14%) for those with a score of 50 or higher (Fig. 1B). The calibration regression slope was 1.02 and its R2 was

0.73 (Fig. 2B), whereas the area under the receiver operating characteristic curve was 0.75 (95% CI, 0.71-0.79) (Fig. 3B). For model 2, we found that the median abbreviated DHRS was 19 (interquartile range, 10-31; range,

-4 to 51). HIV prevalence was 0.4% (31/7708; 95% CI, 0.28%-0.56%) for

those with a score less than 20, 0.43% (11/2543; 95% CI, 0.23%-0.75%) for those with a score of 20 to 29, 1.00% (39/3885; 95% CI, 0.73%-1.36%) for those with a score of 30 to 39, 3.21% (33/1027; 95% CI, 2.26%-4.43%) for those with a score of 40 to 49, and 0.0% (0/21; 95% CI, 0%-13.29%) for those with a score of 50 or higher (or 3.15%; 95% CI, 2.21%-4.34%, for those with a score >=40) (Fig. 1C). The calibration regression slope was 1.5 and its R2 was 0.79 (Fig. 2C), whereas the area under the receiver operating characteristic curve was 0.72 (95% CI, 0.67-0.76) (Fig. 3C).

  1. Discussion

The original DHRS, a clinical Prediction tool for estimating the probability of patients being infected with HIV, provides a verified approach that could be used to target HIV screening in clinical practice [9]. Our findings suggest that the abbreviated version of the DHRS performed fairly when applied retrospectively using data from 2 urban EDs in Baltimore, Maryland, and despite limited sexual risk

A 10

9

8

HIV Prevalence (%)

7

6

5

4

3

2

1

0

B 9

8

HIV Prevalence (%)

7

6

5

4

3

2

1

0

C 5

4.5

4

HIV Prevalence (%)

3.5

3

2.5

2

1.5

1

0.5

0

Abbreviated Denver HIV Risk Score

<20 20-29 30-39 40-49 ? 50

4.57%

2.38%

0.41%

0.29%

0.65%

n = 2691 3420 7052 1554 197

Abbreviated Denver HIV Risk Score

4.29%

2.33%

0%

0.13%

0.59%

<20 20-29 30-39 40-49 ? 50

n = 269 3830 8812 2063 210

Abbreviated Denver HIV Risk Score

3.15%

1.00%

0.40%

0.43%

<20 20-29 30-39 ? 40

n = 7708 2543 3885 1048

behavior information. The original DHRS study reported that 74% and 63% of all patients diagnosed with HIV infection were in higher risk score groups (ie, a score >=30) in the derivation sample and validation sample, respectively [9]. If the DHRS was applied in practice at our site (ie, restrict testing to those with a score >=30), our data demonstrated that 81% of newly diagnosed HIV-infected cases detected using nontargeted screening would have been identified while testing only 58% of the patients in overall approximately 15200 patients. The results from model 2 in our sensitivity analysis, which was an even more limited form of DHRS by excluding all 3 sexual questions, also demonstrated similar accuracy to detect patients at higher risk for HIV with an identification of 63% of Undiagnosed cases while only testing only 33% of overall patients. This method may potentially provide a more efficient and economical alternative in the ED to identify undiagnosed HIV infections as compared nontargeted screening or other “universal” screening methods. A subsequent prospective, before-after study that used the original DHRS demonstrated that targeted screening using the DHRS was more strongly associated with identification of newly diagnosed HIV infection than nontargeted screening in an acute care setting [12].

Although our results externally validated the use of abbreviated version of DHRS, application of limited sexual risk behavior information seemed to be only slightly underestimated observed HIV seropositivity

Fig. 1. A, Prevalence of HIV infection within each risk score category of abbreviated DHRS in 15184 patients of 2 EDs who received a rapid HIV test via ED-based rapid HIV screening program. B, Sensitivity analysis by treating all females having sex with a male. C, Sensitivity analysis by excluding all sexual-related questions. Bars, 95% CI. For C, category of score of 50 or higher was collapsed with score of 40 to 49 because only 21 patients had a score of 50 or more.

for those with higher risk scores in our population (ie, lower predicted HIV seropositive than observed in higher risk score groups; slope, 0.92), while results from the original validation of the DHRS showed almost perfect calibration between predicted and observed HIV prevalences [9]. One possible explanation is that the sexual risk information is important in the prediction of HIV infection; however, another possible explana- tion is that our ED population and risks of HIV infection in our ED patients were different from those in Denver, Colorado, or Cincinnati, Ohio. Evidence is that our EDs are located in Baltimore urban area where HIV seroprevalence is relatively higher than those in above 2 cities [9,13]. In addition, long-term and successful in needle exchange program in the city [14] might also have impacted the importance of 1 risk score variable (ie, IDU in the population). Periodic and site-specific modification of DHRS for the application in clinical settings should be carefully evaluated before its implementation.

A 2.5

Slope=0.92; R2= 0.78

A

Area under the Curve: 0.70 (0.65, 0.75)

B

Area under the Curve: 0.75 (0.71, 0.79)

C

2

Observed HIV Seropositivity (%)

1.5

1

0.5

0

B 2.5

0 0.5 1 1.5 2 2.5

Expected HIV Seropositivity (%)

2

Slope= 1.02; R2= 0.73

Observed HIV Seropositivity (%)

1.5

1

0.5

0

C 2.5

0 0.5 1 1.5 2 2.5

Expected HIV Seropositivity (%)

2

Slope= 1.54; R2= 0.79

Observed HIV Seropositivity (%)

1.5

1

0.5

0

0 0.5 1 1.5 2 2.5

Expected HIV Seropositivity (%)

Area under the Curve: 0.72 (0.67, 0.76)

Fig. 2. A, Calibration of abbreviated DHRS to identify patients at risk for HIV infection, Baltimore 2005 to 2009. B: Sensitivity analysis by treating all females having sex with a male. C, Sensitivity analysis by excluding all sexual-related questions.

Coupled with the Patient Protection and Affordable Care Act passed in March 2010 [15] and the announcement of a Grade “A” recommen- dation on screening for HIV in individuals aged 15 to 65 years from clinicians by the US Preventive services Task Force in the spring of 2013 [16], the cost of HIV testing, a high-value clinical preventive service,

Fig. 3. A, Discrimination of abbreviated DHRS to identify patients at risk for HIV infection, Baltimore 2005 to 2009. B, Sensitivity analysis by treating all females having sex with a male. C, Sensitivity analysis by excluding all sexual-related questions.

should and will be covered through no costs sharing to the beneficiaries. A dramatic increase in the number of ED patients tested in the near future is likely to be expected. Sustainability of ED-based HIV screening programs has become an major concern since the decrease in grant

funding for screening programs from public health agencies as well as uncertainty of reimbursement for HIV screening in the ED [17,18]. It may be more sustainable for such resource-intensive public health initiative if information technology can effectively integrate DHRS with ED electronic patient Tracking systems and electronic medical record systems via novel computerized kiosk systems [19].

Routinely offering HIV testing or nontargeted screening is appraised by many because it may remove exceptionalism and negative stigma around HIV testing [20-22]. Screening using DHRS could attract criticisms as a result of these reasons. However, most current ED-based nontargeted screening programs require substantial internal and external resources and, therefore, only test limited proportions of eligible ED patients while identifying only a small number of previously unDiagnosed infections [23]. Large-scale Prospective trials comparing nontargeted DHRS approach to different forms of nontargeted screening in the ED as well as some qualitative in-depth interview studies in ED patients, clinical providers, ED and hospital financial administrators, and public health policy decision makers are needed to better understand the utilization of DHRS in the ED.

This study has several limitations. First, information routinely collected from our ED-based rapid HIV screening program was not specifically collected for the external validation of the DHRS. Questions to obtain risk information when collected might be addressed or interpreted differently from those questions in the original derivation study. Second, patients might not disclose their risk information to our trained testing facilitators during the brief face-to-face interview. Consequently, the risk score obtained in our study might be under- estimated, especially for those with high-risk behaviors. The calibra- tion curve from our analysis actually demonstrates this, that is [24], the expected HIV seropositivity was slightly lower than the observed one in patients, especially in those with lower risk score (Fig. 2A). Novel risk assessment via touch-screen kiosk or tablet could significantly reduce this type of information bias [24]. Third, the HIV screening programmatic data come from 2 geographically close EDs under the same hospital and health system. These 2 urban EDs are located in a high HIV/AIDS prevalence city where several large-scale HIV inter- vention programs have been implemented [25]. The local HIV epidemic is likely to be different in demographic and risk groups from other locales in the United States. Thus, one should be cautious when trying to generalize our findings to other EDs elsewhere. Another limitation is that, in the sensitivity analysis, all women were considered to have answered “yes” to having sex with males because the question was not asked consistently. Their actual risk is limited by the fact that the actual data were not collected for all female patients. In conclusion, the DHRS possesses potential utilization in ED-based targeted screening program to efficiently identify previously undiagnosed HIV-infected patients, even with only limited sensitive risk information available. Further integration with hospital electronic medical record system and novel delivery methods to remove exceptionalism and stigma

such as kiosks are needed before it is widely implemented.

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