Overuse of Testing and Overuse of Broad-Spectrum Antimicrobial Drugs in Healthcare-Associated Pneumonia

Broad-spectrum therapy has been advocated by the 2005 American Thoracic Society/Infectious Diseases Society of America guidelines for the treatment of healthcare-associated pneumonia (HCAP). These guidelines were formulated based on the hypothesis that patients with HCAP may be at higher risk of having antibiotic-resistant pathogens than patients with community-acquired pneumonia (CAP). The adoption of this guideline has resulted in increased use of broad-spectrum therapy.

But based on current evidence, according to Marcos I. Restrepo, MD, MSc, of the University of Texas Health Science Center at San Antonio, use of broad-spectrum therapy in patients with pneumonia may not be warranted. No systematic evaluation had verified the relationship between HCAP and resistant pathogens. Addressing this gap in the literature, in 2013, Chalmers et al published a systematic review and meta-analysis of the frequency of infection with resistant pathogens in HCAP episodes versus CAP episodes.

In previous publications, resistant pathogens, which include methicillin-resistant Staphylococcus aureus, species of enterobacteraciae, and Pseudomonas aerugenosa, were found to be associated with HCAP; however, the authors of the meta-analysis suspected that publication bias may have influenced these results. Thus, the meta-analysis authors analyzed data in another way: they evaluated whether HCAP was predictive of the presence or absence of resistant pathogens. After adjusting for confounders, including age, comorbidities, and mortality rates, HCAP was not found to be predictive of presence of resistant pathogens (OR, 1.20; 95% CI, 0.85-1.70; P = .30).¹

According to Dr Restrepo, using risk factors to classify people with pneumonia and choosing empiric antibiotic therapy based on those risk factors is not adequate to determine who will have a multidrug-resistant pathogen. Although mortality is higher in patients with HCAP than in patients with CAP, this is primarily due to a higher overall rate of death among nursing home residents with HCAP. According to Dr Restrepo, “The high mortality rate is not driven by [the presence of] multidrug-resistant pathogens.”

With guidelines recommending broad-spectrum antibiotic therapy for patients who have HCAP, the types of antibiotics used in hospitals have changed. Berger and colleagues measured rates of use of different types of antibiotics in adult patients with HCAP over time at more than 100 hospitals across the United States. Over the time period between 2000 and 2009, rates of vancomycin use as initial therapy in HCAP nearly doubled, from 13.1% to 23.3%. In addition, single-agent regimens, such as levofloxacin monotherapy, fell out of favor. A single agent was used in approximately half (48.2%) of patients in 2000, and single agent use fell to just under one-third (30%) of patients by 2009. Guidelines, quality improvement initiatives, and incentivized payment structures have driven these changes in antibiotic use.²

The increase in use of broad-spectrum agents, such as vancomycin, for patients with HCAP may be driven by adoption of pay-for-performance measures that are well intentioned; however, this practice is not consistent with current evidence.

Blood culture testing has been encouraged by The Joint Commission (JCAHO) for patients who develop pneumonia, and use of blood cultures has been incentivized. According to a study published in the Journal of the American Medical Association: Internal Medicine in May 2014 by Makam et al, blood culture use has jumped from 29.4% of patients in 2002 to more than half (51.1%) of patients in 2009—a statistically significant 73% increase in use of the test.³

According to Dr Restrepo, JCAHO’s 2007 recommendations drove this increase in blood culture test use; however, the increased use of blood cultures may not have been associated with quality improvements. Mortality rates have remained stagnant, and the use of blood cultures is not backed by the literature, comments Dr Restrepo.

The theory that HCAP is associated with resistant pathogens has not been borne out in clinical studies and meta-analyses. Use of pay-for-performance measures in the case of HCAP may simply be driving hospitals to overuse blood culture testing, which increases costs, and may also be driving hospitals to overuse broad-spectrum antimicrobial therapies, which increases patients’ risk of developing superinfections.

REFERENCES

1. Chalmers JD, Rother C, Salih W, Ewig S. Healthcare-associated pneumonia does not accurately identify potentially resistant pathogens: a systematic review and meta-analysis. Clin Infect Dis. 2014;58(3):330-339.
2. Berger A, Edelsberg J, Oster G, Huang X, Weber DJ. Patterns of initial antibiotic therapy for community-acquired pneumonia in U.S. hospitals, 2000 to 2009. Am J Med Sci. 2014;347(5):347-356.
3. 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.