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APIC Chapter 13 Journal Club
March 16, 2015
Community-Acquired Pneumonia
Requiring Hospitalization
among U.S. Adults
NEJM – July 30, 2015 373:5
Presented by: Elsa Santos-Cruz IP CIC
Background
The CDC Etiology of Pneumonia in the Community (EPIC) performed an
active surveillance study on the incidence of US population–based
hospitalization due to community acquired pneumonia.
From Jan. 1, 2010 to June 30, 2012 adults greater than 18 years old
were enrolled at 3 hospitals in Chicago. Trained staff screened adult for
enrollment. Weekly teleconference, data audits, and annual site visits
were conducted to ensure uniform procedures among study sites.
Adults eligible were based on clinical assessment by treating clinician
and had evidence of acute infection defined as fever, chills,
hypothermia, leukocytosis, leukopenia, and/or new altered mental
status; had evidence of acute respiratory illness defined as new cough
or sputum production, chest pain, dyspnea, tachypnea, abnormal lung
examination; chest x-ray consistent with pneumonia within 48 hrs.
before and after admission.
Methods
Study Patients: Acute-phase specimens (blood, throat swab, sputum,
and urine) obtained within 72 hrs. hours before or after admission were
included. Pleural fluid was included if obtained within 7 days after
admission.
Convalescent-phase serum was collected after 3-10 weeks.
Radiographic evidence of pneumonia was defined as present if
consolidation (dense or fluffy opacity), other infiltrate (linear and patchy
alveolar or interstitial densities), or pleural effusion.
Control Patients: From Nov. 1, 2011 to June 30, 2012, asymptomatic
adults from Nashville who presented to a general medicine clinic were
enrolled weekly. Nasopharyngeal and oropharyngeal swabs were
obtained to assess respiratory pathogens.
Study Population
Adults with Community-Acquired Pneumonia Requiring Hospitalization
n = 2320
Age group
18 - 49 yr
n
701
=
%
30
50 - 64 yr
787
=
34
65 - 75 yr
517
=
22
≥ 80 yr
315
=
14
Patient Data/Outcomes






2320 pts with radiologic evidence of pneumonia
Median age = 57
Median LOS in hospital = 3 days
498 pts (21%) admitted to ICU
131 (6%) patients required mechanical ventilation
52 (2%) patients expired due to PNA
 78% of blood cultures were collected before start of antibiotics
• 7% vs 3% were positive if collected before/after abx started (p<.002)
 Up to 12% of other cultures were collected before start of antibiotics
 Pts >80 yrs had ~25x increased risk of hospital admission vs. pts 18-49 yrs
 Pts 65-79 yrs had ~9x increased risk of hospital admission vs. pts 18-49 yrs
Results
Specific pathogens detected:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Human rhinovirus
Influenza A or B
Streptococcus pneumoniae
Human metapneumovirus
Respiratory syncytial virus (RSV)
Parainfluenza virus
Coronavirus
Mycoplasma pneumoniae
Staphylococcus aureus
Adenovirus
Legionella pneumophilia
Enterobacteriaceae
Results
Patients with a positive result (%):
No pathogens detected
=
62 %
Viral pathogens only
=
22 %
Bacterial pathogens only
=
11 %
38%
Bacterial & viral co-detection
=
3%
Viral-viral co-detection
=
2%
Fungal or mycobacterial detection =
1%
Viruses were identified in 22% of all patients
Bacteria were identified in 14% of all patients
Results
Results
Control
Nasopharyngeal and oropharyngeal swabs pathogen detection:
Asymptomatic controls
238
=
2%
Patients with pneumonia 192
=
27 %
P < 0.001
Limitations
I.
Unable to enroll all eligible patients; over 65 who were undergoing
invasive mechanical ventilation were excluded.
II.
Unable to collect all specimen types, which could lead to
underestimation or overestimation of pathogen-specific rates
III. Sensitivities and specificities of available diagnostic tests are imperfect.
Urinary pneumococcal antigen can be detected for weeks after the
onset of pneumonia and recent vaccination can lead to false positive
results.
IV. Unable to enroll symptomatic controls for the entire study period.
Possibility of missing the detection of commonly circulating pathogens.
V. Overlapping clinical and radiologic features of pneumonia.
Misclassification of symptoms such as chronic lung disease and
congestive heart failure.
Conclusion
Community acquired pneumonia requiring hospitalization is
markedly higher among older adults.
Respiratory viruses were detected more frequently than bacterial
pathogens. This may reflect the direct and indirect benefit of
bacterial vaccines and insensitive diagnostic test.
These data indicate improving coverage and effectiveness of
influenza and pneumococcal vaccines.
Developing effective vaccines and treatment for Human
metapneumovirus (HMPV), Respiratory syncytial virus (RSV) and
parainfluenza virus infection.