Community-Acquired Pneumonia and Hospitalization

Elizabeth Lai, Mercer University College of Pharmacy

The Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia (CAP) in Adults states that diagnosis and treatment depends on the severity of CAP.  The guidelines state that combination empiric therapy is recommended for severe CAP.  Outpatient treatment in healthy individuals may consist of a macrolide or doxycycline.  Inpatient, non-intensive care unit (ICU) treatment may include a respiratory fluoroquinolone or a ß-lactam plus a macrolide.  The guidelines state that the ultimate goal of therapy is eradicating the infecting organism and resolving the disease.1

According to Pharmacotherapy: A Pathophysiologic Approach, CAP is commonly caused by Streptococcus pneumoniae and treatment may include humidified oxygen for hypoxemia, bronchodilators if bronchospasm is present, rehydration fluids, and chest physiotherapy for marked accumulation of retained respiratory secretions.  Antibiotics should be used on presumed causative pathogens.  The signs and symptoms of pneumonia includes abrupt onset of fever, chills, dyspnea, and productive cough, rust colored sputum or hemoptysis, and pleuritic chest pain.2

According to the Diagnosis and Treatment of Community-Acquired Pneumonia, choosing inpatient and outpatient treatment is an important factor due to possible risk of death.  The recommended empiric treatment by the Therapeutic Working Group of Centers for Diseases Control and Prevention (CDC) suggests using fluoroquinolones sparingly due to antibiotic resistance.  The CDC recommends outpatient oral empiric antibiotics of macrolide, doxycycline, or an oral ß-lactam and inpatient treatment with an intravenous ß-lactam, cefotaxime, or combination of ampicillin/sulbactam with a macrolide.3

Title: Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults
Design Prospective, population-based study; N = 2,488
Objective To calculate population-based incidence rates of community-acquired pneumonia requiring hospitalization according to age and pathogen
Study Groups Age group 18-49 years, 50-64 years, 65-79 years, and ≥ 80 years
Methods Patients enrolled from three hospitals in Chicago and two in Nashville.  They were admitted to the hospital if they had evidence of acute infection, documented fever or hypothermia, leukocytosis or leukopenia, or new altered mental status, evidence of an acute respiratory illness, or evidence consistent with pneumonia as assessed by means of chest radiography by means of chest radiography by the clinical team within 48 hours before or after administration.  Blood, urine, and respiratory specimens were collected for testing.
Duration January 2010 to June 2012
Primary Outcome Measure Incidence rates of community acquired pneumonia
Baseline Characteristics Characteristic Adults with Radiographic Evidence of Pneumonia (N = 2320)
Race of ethnic group, (%)
Non-Hispanic white 1086 (47)
Non-Hispanic black 898 (39)
Hispanic 243 (10)
Other 93 (4)
Age group, (%)
18-49 years 701 (30)
50-64 years 787 (34)
65-79 years 517 (22)
≥ 80 years 315 (14)
Duration from illness onset to hospital presentation – days
Median 4
Interquartile range 2-7
Any underlying condition, (%) 1817 (78)
Chronic lung disease 968 (42)
Chronic heart disease 810 (35)
Immunosuppression 685 (30)
Diabetes mellitus 597 (26)
Status regarding receipt of vaccine or treatment – no./total no. (%)
Seasonal influenza vaccination 448/1898 (24)
Pneumococcal vaccination in adults ≥65 years of age 308/704 (44)
Outpatient antibiotic use 249/2232 (11)
Inpatient antibiotic use 2287/2320 (99)
Radiographic finding, (%)
Consolidation 1447 (62)
Alveolar or interstitial infiltrate 920 (40)
Pleural effusion 714 (31)
Pneumonia severity index
Median 76
Interquartile range 52-103
Risk class, (%)
1-3 1510 (65)
4 606 (26)
5 204 (9)
Results Variable Incidence of Pneumonia-Related Hospitalization (95% CI)
18-49 years 6.7 (6.1-7.3)
50-64 years 26.3 (24.1-28.7)
65-79 years 63.0 (56.4-70.3)
≥ 80 years 164.3 (141.9-189.3)
Pathogen detected
Human rhinovirus 2.0 (1.7-2.3)
Influenza A or B virus 1.5 (1.3-1.8)
Streptococcus pneumoniae 1.2 (1.0-1.4)
Human metapneumovirus 0.9 (0.7-1.2)
Parainfluenza virus 0.8 (0.6-1.0)
Respiratory syncytial virus 0.7 (0.5-0.9)
Coronarvirus 0.6 (0.4-0.7)
Mycoplasma pneumoniae 0.5 (0.4-0.7)
Staphylococcus aureus 0.4 (0.3-0.6)
Legionella pneumophila 0.4 (0.2-0.5)
Adenovirus 0.4 (0.2-0.5)
Adverse Events Common Adverse Events: N/A
Serious Adverse Events: N/A
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions The incidence of community-acquired pneumonia requiring hospitalization was highest among the oldest adults. Despite current diagnostic tests, no pathogen was detected in the majority of patients.  Respiratory viruses were detected more frequently than bacteria.

The study revealed that higher rates of CAP were seen in those greater than 80 years of age.  In severely ill patients, the presence of S. pneumoniae, S. aureus, and Enterobacteriaceae were significantly more common, and consisted of 16% of detected pathogens in ICU patients vs. 6% in non-ICU.  This study had an annual incidence of CAP requiring hospitalization of 24.8 cases per 10,000 adults, which was similar to the 26.7 cases per 10,000 adults in a prospective study conducted in Ohio in 1991.  Estimates may have been lower due to differences in enrollment criteria.  Patients age 65 years and older and undergoing invasive mechanical ventilation were less likely to be enrolled and not all specimen types were available, leading to poor estimation of pathogen-specific rates.  The sensitivities and specificities of tests may also play a role in improper detection of pathogens.

References

[List sources for this section here.]

  1. Mandell L, Wunderink R, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis 2007;44 (Suppl 2):S27–S72.
  2. Blackford MG, Glover ML, Reed MD. Chapter 85. Lower Respiratory Tract Infections. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L. eds. Pharmacotherapy: A Pathophysiologic Approach, 9e. New York, NY: McGraw-Hill; 2014. http://accesspharmacy.mhmedical.com/content.aspx?bookid=689&Sectionid=45310531. Accessed July 23, 2015.
  3. Lutfiyya MN, Henley E, Chang LF. Diagnosis and Treatment of Community-Acquired Pneumonia. Am Fam Physician. 2006 Feb 1;73(3):442-450.
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