CMS indicates Centers for Medicaid & Medicare Services; ED, emergency department; JCAHO, Joint Commission on Accreditation of Healthcare Organizations; UTI, urinary tract infection. Blood culture collection data were not recorded in the 2005 and 2006 surveys. In 2002, the JCAHO and CMS announced a core measure for routine blood culture collection in the ED for all patients hospitalized with community-acquired pneumonia to benchmark the quality of care. This was subsequently revised in 2005 to focus only on intensive care unit admissions. Practice guidelines for the management of pneumonia were revised at the beginning of 2007 to recommend routine blood cultures only for patients with severe community-acquired pneumonia. aDifference in the trend lines was evaluated by testing the interaction term of year and condition in a regression model using the collection of a blood culture as the outcome variable.
eFigure. Study Flow Diagram of US Emergency Department Visits
eTable. Characteristics of Visits to the ED by Patients Hospitalized for Community-Acquired Pneumonia From 2002 Through 2010a
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Makam AN, Auerbach AD, Steinman MA. Blood Culture Use in the Emergency Department in Patients Hospitalized for Community-Acquired Pneumonia. JAMA Intern Med. 2014;174(5):803–806. doi:10.1001/jamainternmed.2013.13808
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Routine blood cultures for all patients hospitalized with community-acquired pneumonia have limited utility, and false-positive results lead to inappropriate antimicrobial use and longer hospital stays.1 As a result, performance measures and practice guidelines that promoted obtaining blood cultures in all such patients were modified from 2005 through 2007 to recommend routine collection in only the sickest patients.1,2 Using a national sample of emergency department visits, we examined patterns of obtaining cultures in adults hospitalized with community-acquired pneumonia.
We analyzed data from the 2002 through 2010 National Hospital Ambulatory Medical Care Surveys (NHAMCS), a probability sample of emergency department visits in the United States.3 The years 2005 and 2006 are omitted because the surveys did not collect blood culture use during this period.
We included all visits by patients 18 years or older with community-acquired pneumonia (International Classification of Diseases, Ninth Revision codes 481-486) who were subsequently hospitalized. Blood culture collection during the visit was recorded as a checkbox on the NHAMCS data collection form. As a control group, we examined the trend in collecting cultures in patients hospitalized for a urinary tract infection (International Classification of Diseases, Ninth Revision codes 595.00 and 599.00), a diagnosis with no change in recommendations during the study period.
Analyses accounted for the complex survey design to reflect national estimates. Trends in culture use were evaluated with linear regression. We applied logistic regression to assess predictors of culture use after revisions in recommendations using combined data from 2007 through 2010. This study was exempt from review by our institutional review boards.
This study included 1487 visits, representing 5.1 million visits by adult patients hospitalized with community-acquired pneumonia (more information is provided in the eTable and eFigure in the Supplement). The proportion of cultures collected in patients hospitalized with community-acquired pneumonia increased from 29.4% (95% CI, 21.9%-38.3%) in 2002 to 51.1% (95% CI, 41.8%-60.3%) in 2010 (P = .03 for trend), a 73.4% relative increase (Figure). In contrast, culture rates for urinary tract infection remained stable (P = .47), with a substantial difference in culture use between the 2 conditions over time (difference of 3.2% per year; 95% CI, 1.6%-4.8%).
In multivariable analysis (Table), disease severity did not predict culture collection, and admission to the intensive care unit was associated with a lower odds of obtaining cultures. Several nonclinical factors were strong predictors, including hospital ownership and region.
In this national study, we found that the collection of blood cultures in patients hospitalized with community-acquired pneumonia continued to increase despite recommendations for a more narrow set of indications. Furthermore, nonclinical factors were powerful predictors of blood culture use rather than disease severity and intensive care unit admission status.
One potential explanation for increasing culture rates is that the measure (PN-3b) announced in 2002 by the Centers for Medicaid & Medicare Services and the Joint Commission on Accreditation of Healthcare Organizations mandated that if a culture is collected in the emergency department, it should be done before antibiotic administration.5 This measure may encourage providers to reflexively order cultures in all patients admitted with community-acquired pneumonia in whom antibiotic administration is anticipated, even though cultures are strongly indicated in only the sickest patients. Given rising trends in obtaining cultures in low-risk patients, we advocate for the Joint Commission on Accreditation of Healthcare Organizations and Centers for Medicaid & Medicare Services to reexamine this measure with consideration of eliminating it entirely to discourage overuse.
One limitation of our study was the omission of data from 2005 through 2006, prohibiting an evaluation of whether culture rates slowed down after revisions in recommendations. Also, there may be misclassification of culture use, but this would likely be nondifferential and bias our findings for intensive care unit status toward the null.
The appropriate use of cultures could reduce potential harms from inappropriate antibiotic use and longer hospital stays,6 as well as decrease the summative cost of the test itself.7 Further attention is warranted to the judicious use of blood cultures in the management of pneumonia.
Corresponding Author: Anil N. Makam, MD, MAS, Division of General Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9169 (email@example.com).
Published Online: March 10, 2014. doi:10.1001/jamainternmed.2013.13808.
Author Contributions: Dr Makam had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Acquisition of data: Makam.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Makam, Auerbach.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Makam.
Administrative, technical, or material support: Makam, Steinman.
Study supervision: Auerbach, Steinman.
Funding/Support: Dr Makam reported working on this project while he was a primary care research fellow at the University of California, San Francisco, funded by a National Research Service Award (training grant T32HP19025-07-00).
Role of the Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: D. B. Grinsfelder, MPH, Division of Outcomes and Health Services Research, The University of Texas Southwestern Medical Center, Dallas, assisted in creating the Figure. He was not compensated for his services.