Scholarly article on topic 'Rapid urine antigen testing for Streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers'

Rapid urine antigen testing for Streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers Academic research paper on "Health sciences"

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Pneumococcus / Community acquired pneumonia / Urine antigen test / Rapid diagnostics

Abstract of research paper on Health sciences, author of scientific article — Aaron M. Harris, Susan E. Beekmann, Philip M. Polgreen, Matthew R. Moore

Abstract Streptococcus pneumoniae (pneumococcus) is the most common bacterial etiology of community-acquired pneumonia (CAP) in adults, a leading cause of death. The majority of pneumococcal CAP is diagnosed by blood culture, which likely underestimates the burden of disease. The 2007 CAP guidelines recommend routine use of the rapid pneumococcal urinary antigen (UAg) test. To assess the how pneumococcal UAg testing is being used among hospitalized adult CAP patients and what barriers restrict its use, a Web-based survey was distributed in 2013 to 1287 infectious disease physician members of the Emerging Infectious disease Network of the Infectious Disease Society of America. Of 493 eligible responses, 65% use the pneumococcal UAg test. The primary barrier to UAg use was availability (46%). UAg users reported ordering fewer other diagnostic tests and tailoring antibiotic therapy. Increased access to UAg tests could improve pneumonia management and pneumococcal CAP surveillance.

Academic research paper on topic "Rapid urine antigen testing for Streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers"

Accepted Manuscript

Rapid urine antigen testing for streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers

Aaron M. Harris, Susan E. Beekmann, Philip M. Polgreen, Matthew R.

PII: S0732-8893(14)00200-4

DOI: doi: 10.1016/j.diagmicrobio.2014.05.008

Reference: DMB 13611

To appear in: Diagnostic Microbiology and Infectious Disease

Received date: 17 March 2014

Revised date: 8 May 2014

Accepted date: 10 May 2014

Please cite this article as: Harris Aaron M., Beekmann Susan E., Polgreen Philip M., Moore Matthew R., Rapid urine antigen testing for streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers, Diagnostic Microbiology and Infectious Disease (2014), doi: 10.1016/j.diagmicrobio.2014.05.008

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Title: Rapid Urine Antigen Testing for Streptococcus pneumoniae in Adults with Community-Acquired Pneumonia: Clinical Use and Barriers

Authors: Aaron M. Harrisa,b, Susan E. Beekmannc, Philip M. Polgreenc, Matthew R. Mooreb aRespiratory Disease Branch, Centers for Disease Control and Prevention, Atlanta, Georgia bEpidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia cUniversity of Iowa Carver College of Medicine, Iowa City, Iowa

Key words: pneumococcus; community acquired pneumonia; urine antigen test; rapid diagnostics Running title: Pneumococcal urine antigen survey

Corresponding Author

Aaron Harris MD

Respiratory Diseases Branch

Centers for Disease Control and Prevention

1600 Clifton Road NE, MS C-25

Atlanta, GA 30333

Tel: 404-639-2912

Fax: 404-638-5617

email: ieo9@cdc.gov

Pneumococcal urine antigen survey Full-length article

• Word count: 1486

• References: 13

• Abstract: 146

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Pneumococcal urine antigen survey Abstract

Streptococcus pneumoniae (pneumococcus) is the most common bacterial etiology of community acquired pneumonia (CAP) in adults, a leading cause of death. The majority of pneumococcal CAP is diagnosed by blood culture, which likely underestimates the burden of disease. The 2007 CAP guidelines recommend routine use of the rapid pneumococcal urinary antigen (UAg) test. To assess the how pneumococcal UAg testing is being used among hospitalized adult CAP patients and what barriers restrict its use, a web-based survey was distributed in 2013 to 1287 infectious disease physician members of the Emerging Infectious disease Network of the Infectious Disease Society of America. Of 493 eligible responses, 65% use the pneumococcal UAg test. The primary barrier to UAg use was availability (46%). UAg users reported ordering fewer other diagnostic tests and tailoring antibiotic therapy. Increased access to UAg tests could improve pneumonia management and pneumococcal CAP surveillance.

1. Introduction

Streptococcus pneumoniae (pneumococcus) is the most common bacterial etiology of community acquired pneumonia (CAP) in adults (Klugman et al., 2008), a leading cause of morbidity and mortality in the United States (Kung et al., 2008). In recent years, the incidence of invasive pneumococcal disease, including bacteremic pneumococcal pneumonia in adults, has been declining as a result of routine vaccination of children with pneumococcal conjugate vaccines (Pilishvili et al., 2010). The majority of pneumococcal pneumonia cases are diagnosed by blood culture. However, because only about 25% of pneumococcal pneumonia cases are associated with bacteremia, clinicians miss opportunities for a pathogen-specific CAP diagnosis (Said et al., 2013). In addition, the burden of pneumococcal disease and impact of pneumococcal conjugate vaccine are likely underestimated (Said et al., 2013). Culture-independent diagnostic tests could improve clinical care and non-invasive pneumococcal disease surveillance.

The pneumococcal urinary antigen (UAg) test was licensed by the FDA in 1999 and has a reported sensitivity of 50-80% and a specificity of >90%(Mandell et al., 2007). The 2007 IDSA/ATS guidelines for the management of CAP recommend the routine use of the pneumococcal UAg test as an adjunct to blood cultures for hospitalized patients with severe CAP (Mandell et al., 2007). However, physicians do not always follow clinical practice guidelines (Cabana et al., 1999). To understand how the pneumococcal UAg test is being used in clinical practice and what barriers restrict its use, we performed a web-based survey of practicing infectious disease (ID) physicians regarding their use of the pneumococcal UAg test among hospitalized adult patients with CAP.

2. Materials and methods

We surveyed ID physician members of the Infectious Diseases Society of America (IDSA)'s, Emerging Infections Network (EIN). The EIN is a provider-based emerging infections sentinel network

funded by the Centers for Disease Control and Prevention to gather information about clinical aspects of infectious diseases (Pillai et al., 2014). An 11-question survey was distributed via e-mail or facsimile to 1,287 EIN members who care for adult patients from the USA, Puerto Rico, and Canada in May 2013. Two reminders were sent to non-responders over three weeks.

The physicians were asked how frequently they use the pneumococcal UAg test and reasons why they do or do not use the test. We also inquired about the clinical setting in which the test is used and how results of the pneumococcal UAg test influence clinical decision making. For comparison, the survey also asked about use of blood cultures in CAP patients. Only respondents who reported that they care for adult hospitalized CAP patients were included in the analysis.

A descriptive analysis was performed on completed questions; denominators for certain questions varied, as not all physicians responded to all questions. Comparisons between groups were made by chi-square analysis using SAS version 9.3. P values of <0.05 were considered statistically significant.

3. Results

There were 592 (46%) respondents, consistent with other EIN surveys (Gundlapalli et al., 2013). Characteristics of respondents, including patient population, practice setting, and state of residence, did not differ significantly from those of non-respondents. However, respondents were significantly more likely than non-respondents to have at least 15 years of clinical ID experience (P<0.001). Ninety-nine responses were excluded because the physicians reported that they did not treat hospitalized adult patients with CAP, leaving a final sample of 493.

Of these respondents, 319 (65%) use the pneumococcal UAg test and 485 (98%) use blood cultures in clinical practice. Of the physicians who use the pneumococcal UAg test, 71% had access to

the test in their clinical lab and 29% order it as a send-out to another laboratory. Respondents who do not use the UAg test (N=174, 35%) provided several reasons for not doing so, including lack of availability (46%), results not available in a timely fashion (33%), a belief that results would not influence clinical decision-making (32%), perceived poor reliability (12%), high cost (9%), and inability to obtain susceptibility results (7%).

We observed wide geographic variations in use of the pneumococcal UAg test (Table 1), with highest use in southern regions (range 74-84%) and lower use among northern and western regions of the country (range 48-68%). There were no significant differences in UAg usage with years of experience since completing ID training. There was a non-significant (P=0.06) trend toward differences in UAg usage with community (74%) and Veterans Affairs/Department of Defense (72%) hospitals using the UAg test more than teaching (60%) and city or county hospitals (60%).

Because blood cultures have been a routine diagnostic method among CAP patients for many years, we compared the frequency of UAg testing to blood culture. Among those who do use blood cultures or UAg, blood cultures are used more commonly among all patients with CAP whereas UAg testing tends to be used only in selected CAP patients (Table).

The UAg is recommended to be used for inpatient settings so we asked physicians about the clinical settings in which they use UAg and blood cultures. Of those respondents who use these tests, over 93% of respondents order blood cultures and over 87% of respondents order the UAg test for inpatients with CAP. Even greater (P<0.001) proportions of respondents indicated use of these tests for ICU patients (Table 2).

Over 80% of respondents who use UAg reported that results influenced clinical decision-making (Table). The most common changes in clinical management related to the ordering of fewer other

diagnostic tests, narrowing of antibiotic regimens, and shortening of antibiotic courses for positive UAg results.

Since ID physicians usually see CAP patients after initial evaluation and management, we inquired about respondent's perception of non-ID physicians' use of blood cultures and UAg (Table 2). Non-ID physicians were perceived to use the UAg test some of the time for CAP patients (48%), and blood cultures most of the time or always (69%). Few non-ID physicians were perceived to use the UAg always (3%) or most of the time (17%).

4. Discussion

Infectious disease diagnostics are shifting from the traditional culture-based methods to culture-independent methods such as the pneumococcal UAg test. Our survey indicates that 65% of ID physicians use the pneumococcal UAg test routinely; however, they report that <20% of non-ID physicians were perceived to use UAg testing most of the time or always. Importantly, ID physicians alter clinical management in response to a positive UAg test in ways similar to a positive blood culture for S. pneumoniae.

Improved CAP diagnostic yield may lead to better clinical practice. The recommended empiric CAP treatment for inpatients is broad, including either a fluoroquinolone or a third generation cephalosporin plus a macrolide, to cover many possible pneumonia-causing organisms (Bartlett 2011). Data support use of p-lactams in adult CAP patients with a positive UAg test (Guchev et al., 2005; Stralin and Holmberg 2005), and results from our survey indicate that the majority of ID physicians who use the UAg test narrow therapy in response to a positive test. The main reasons physicians reported for not using the test was lack of ready availability of the UAg test in their clinical settings or lack of timeliness as the test is often sent out for analysis. For send-out testing, the delay in result reporting could be up to

a week which may be too late to alter treatment. Therefore, healthcare centers could improve the quality of care for adult CAP patients with pathogen-directed therapy by making this test more available.

Respondents listed potential reasons in the free-text comments of the survey for why UAg is not available in their clinical setting, and included: cost, extra training due to the Clinical Laboratory Improvement Amendments (CLIA), and shelf life of the UAg kit. Regarding cost, the UAg test is estimated to cost between $30-40 per test in the United States. An algorithm to determine cost savings of UAg in Europe 2003 showed that patients started empirically on narrow-spectrum (less expensive therapy) and used UAg had cost savings of ~$9.16 compared to those started empirically on broad-spectrum (expensive therapy), which had cost excess of ~$27.41 (Oosterheert et al., 2003). However, it is unclear from this study how cost savings would be impacted if patients started on empiric therapy subsequently had therapy tailored toward pneumococcus after a positive test. Unfortunately, while UAg testing is rapid, and easy to use, CLIA restricts use to trained technicians in a CLIA certified laboratory. Lastly, the shelf life of the UAg kit is at least 2 years. We suggest that the UAg test could be integrated into electronic medical order sets to increase clinical use, and results of this survey be considered in future CAP clinical guidelines to routinely recommend UAg testing for all CAP patients.

Current pneumococcal surveillance depends on culture-based methods (Williams et al., 2011). Non-bacteremic pneumococcal pneumonia is often not diagnosed with culture-based methods. Therefore, the burden of non-bacteremic pneumococcal pneumonia is difficult to estimate but is clearly larger than the burden of bacteremic pneumococcal pneumonia (Said et al., 2013). Culture-independent tests, such as the pneumococcal UAg test, may be an important tool to incorporate into surveillance systems to better estimate the burden of pneumococcal pneumonia.

Results of the survey should be interpreted with consideration of important limitations. The 46% of individuals who responded to our survey may not be representative of those who did not respond.

The EIN network is limited to ID physicians who belong to IDSA, and is not representative of all physicians. Non-ID clinicians are usually the first to start the evaluation of hospitalized CAP patients, and were not surveyed directly. In addition, respondents' reported use of the UAg test may differ from their actual practice.

Inappropriate antibiotic use with cephalosporins and macrolides has contributed to emerging antibiotic resistance for pneumococci (Hicks et al., 2011); thus, pathogen-specific CAP diagnosis remains critical. While a positive UAg test does not provide susceptibility results, it can reassure clinicians that other pathogens (e.g., Staphylococcus aureus) requiring broader-spectrum therapy are less likely to be playing a role in a particular patient's illness. Our survey suggests that physicians with access to the test are using rapid culture-independent diagnostics for hospitalized adult CAP patients more frequently. We suggest that use of the UAg test would improve quality of care by allowing clinicians to use more targeted therapy, and may be incorporated into population-based surveillance systems to better estimate the burden of non-bacteremic pneumococcal CAP.

Pneumococcal urine antigen survey Acknowledgments

Financial support: This work was supported by a cooperative agreement 5U50CK000187 from the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. All authors report no conflicts of interest. The authors would like to thank members of IDSA's emerging infections network for participating in this survey.

References

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Cabana, MD, et al. Why don't physicians follow clinical practice guidelines? A framework for improvement. JAMA,1999 282, 1458-1465.

Guchev, IA, et al. Management of nonsevere pneumonia in military trainees with the urinary antigen test for Streptococcus pneumoniae: an innovative approach to targeted therapy. Clin Infect Dis,2005 40, 1608-1616.

Gundlapalli, AV, et al. Perspectives and concerns regarding antimicrobial agent shortages among infectious disease specialists. Diagn Microbiol Infect Dis,2013 75, 256-259.

Hicks, LA, et al. Outpatient antibiotic prescribing and nonsusceptible Streptococcus pneumoniae in the United States, 1996-2003. Clin InfectDis,2011 53, 631-639.

Klugman, KP, et al. Novel approaches to the identification of Streptococcus pneumoniae as the cause of community-acquired pneumonia. Clin Infect Dis,2008 47 Suppl 3, S202-206.

Kung, HC, et al. Deaths: final data for 2005. Natl Vital Stat Rep,2008 56, 1-120.

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consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis,2007 44 Suppl 2, S27-72.

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Pilishvili, T, et al. Sustained reductions in invasive pneumococcal disease in the era of conjugate vaccine. J Infect Dis,2010 201, 32-41.

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treatment of community-acquired pneumonia. Clin Infect Dis,2005 41, 1209-1210.

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Table 1. Reported usage and availability of the pneumococcal urinary antigen test (UAg) by region, clinical experience, and hospital type

Total responded N=493 (38%) UAg usage N=319 (65%) UAg available in clinical lab N=217 (68%) UAg available as send-out test N=87 (27%)

Region, N (%)

East South Central 19 (33) 16 (84) 12(75) 3 (19)

South Atlantic 75 (33) 62 (83) 38 (61) 23(37)

West South Central 34 (40) 25 (74) 15 (60) 9 (36)

East North Central 76 (40) 52 (68) 43 (83) 8 (15)

Mountain 34 (47) 23 (68) 18 (78) 5 (22)

New England 40 (43) 26 (65) 18(69) 7 (27)

West North Central 50 (40) 31 (62) 23(74) 6 (19)

Mid Atlantic 76 (39) 44 (58) 33 (75) 5 (11)

Pacific 80(36) 38 (48) 16(42) 22 (58)

Canada 8 (38) 2 (25) 1 (50) 1 (50)

Years since ID fellowship, N (%)

<5 117 (38) 81 (69) 55 (68) 21(26)

5-14 112 (29) 75(67) 50 (67) 21(28)

15-24** 129 (43) 74 (57) 49 (66) 22 (30)

>=25 134 (47) 89(66) 63 (71) 23(26)

Primary hospital type, N (%)

Community 147 (38) 109 (74) 75(69) 28(26)

VA/DOD hospital 32 (39) 23(72) 13 (57) 9 (39)

Non-university teaching 143 (40) 88 (62) 66 (75) 19(22)

City/County hospital 20 (53) 12(60) 5 (42) 6 (50)

University 149 (36) 86(57) 57 (66) 25(29)

Other 2 (14) 1 (50) 1 (100) 0 (0)

Table2. Use of blood culture and pneumococcal urinary antigen test for adult patients with community acquired pneumonia.

Blood culture (%) Urinary antigen test (%) P-value

Do you order blood cultures or the pneumococcal urine antigen (UAg) test for patients with CAP in your clinical practice?

Yes 485 (98) 4 319 (65) <0.001

Of those who use the test, where is the test use d?*

Outpatient 75 (16) 48 (15) 0.918

Inpatient, non ICU 445 (93) 271 (87) 0.005

Inpatient, ICU 469 (98) 299 (96) 0.089

Other 17 (4) 13 (4) 0.657

Of those who use the test, which patients are te sted?*

All CAP patients 306 (64) 133 (42) <0.001

The majority of CAP patients 133 (28) 109 (35) 0.034

Only certain CAP patients, ie ICU 41 (9) 64 (20) <0.001

Other 1 (<1) 8 (3) 0.002

How do results influence clinical management f< r a positive res ult?**

Narrow antibiotic regimen 433 (90) 262 (84) 0.012

Shorten antibiotic course 117 (24) 88 (28) 0.219

Order fewer diagnostic tests 304 (63) 209 (67) 0.266

No change in clinical management 7 (1) 10 (3) 0.096

Other 32 (7) 6 (2) 0.002

How often do non-infectious disease clinicians use these tests for patients with CAP?***

Always 65 (13) 12 (3) <0.001

Most of the time 275 (56) 76 (17) ^ <0.001

Some of the time 142 (29) 213 (48) <0.001

Not at all 6 (1) 125 (28) <0.001

Not sure 1 (<1) 14 (3) <0.001

*Responses varied for blood culture (N=479) and UAg (N=312). **Responses varied for blood culture (N=480) and UAg (N=311). ***Responses varied for blood culture (N=489) and UAg (N=440).