START (Stewardship Tactics for Antimicrobial Resistance Trends)

BACKGROUND: Among infectious diseases, community-acquired pneumonia (CAP) is the leading cause of death in the United States and is associated with a substantial economic burden to the health care system. Initiating appropriate empiric therapy can be challenging given elevated resistance rates among Streptococcus pneumoniae strains. OBJECTIVE: To present current recommendations for management of CAP with respect to (a) choosing the appropriate site of care, and (b) antimicrobial selection based on bacterial etiology and the prevalence of resistance. SUMMARY: Mortality prediction tools, such as the PORT (Pneumonia Outcomes Research Team) Severity Index, CURB-65 (Confusion, Urea concentration, Respiratory rate, Blood pressure, and age > 65), or CRB-65 (Confusion, Respiratory rate, Blood pressure, and age > 65), can be invaluable in determining which CAP patients require hospitalization. These tools can help reduce overall costs for CAP by limiting hospitalizations of low-risk patients. S. pneumoniae remains the most common causative pathogen for CAP across all disease severities, and elevated rates of resistance to penicillin and macrolides can hinder selection of appropriate antimicrobial therapy. Antimicrobial resistance can impact clinical outcomes, including increasing the risk of treatment failure and breakthrough bacteremia. Current management guidelines recommend monotherapy with a respiratory fluoroquinolone or combination therapy with a β-lactam and a macrolide (for patients admitted to the general medical ward) or with a β-lactam and either a respiratory fluoroquinolone or a macrolide (for patients admitted to the intensive care unit [ICU] and who do not have risk factors for methicillin-resistant S. aureus or Pseudomonas ). Optimized dosing regimens aim to ensure that pharmacokinetic and pharmacodynamic targets are met to achieve successful clinical outcomes and minimize resistance development. CONCLUSION: Effective management of patients with CAP requires selection of the proper site of care and appropriate empiric antimicrobial. Given the elevated rates of resistance among S. pneumoniae, local resistance patterns must be considered when choosing empiric therapy. J Manag Care Pharm. 2009;15(2)(Suppl):S5-S11 Copyright © 2009, Academy of Managed Care Pharmacy. All rights reserved. THOMAS M. FILE, Jr., MD, MSc, is Professor of Internal Medicine, Master Teacher, and Head, Infectious Disease Section, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio, and Chief, Infectious Disease Service, Summa Health System, Akron, Ohio. CORRESPONDENCE: Thomas M. File, Jr., MD, MSc, 75 Arch Street, Suite 105, Akron, OH 44304. Tel.: 330.375.3894; Fax: 330.375.6680; E-mail: [email protected] Author Community-acquired pneumonia (CAP) along with influenza is the leading cause of death among infectious diseases in the United States (and eighth leading cause of death overall).1 Five to 6 million cases occur each year, with persons 65 years or older accounting for about one million cases.2 An estimated 20% of the patients with CAP require admission to the hospital.3 The mortality rate of patients who require admission to the hospital averages 12% overall but increases to 30%-40% for those with severe CAP who require admission to the ICU.2 This compares to a mortality rate of less than 1% among patients with CAP treated on an outpatient basis.4 In addition to the clinical consequence of CAP, the economic cost is extraordinary, with one study estimating the cost for each inpatient episode of CAP to exceed $10,000.3 It is noteworthy that these clinical and economic consequences of CAP occur against the backdrop of effective antimicrobial agents available for the treatment of respiratory tract infections. Many factors must be considered in order to select an appropriate antimicrobial regimen for effectively treating patients with CAP. The first and foremost consideration should be whether an antimicrobial agent is warranted. Viral infections can play a role in a significant portion of patients hospitalized for CAP, with estimates ranging from 1% to 23%.5 Several observational studies have shown that over 50% of the patients with viral respiratory tract infections are inappropriately prescribed antimicrobial agents.6,7 Antimicrobial overuse and inappropriate antimicrobial selection have been associated with increased drug resistance among several respiratory pathogens. In addition, unnecessary use increases cost and potential adverse events. Increasing resistance has made judicious use of antimicrobials an imperative,8 and differentiating viral bronchitis from pneumonia is key in limiting unnecessary antimicrobial use. Unfortunately, there is lack of rapidly available, cost-effective diagnostic tests that reliably differentiate self-limiting viral infections from bacterial infections. However, practice guidelines can offer pragmatic criteria for better antimicrobial usage.9 Once a patient is diagnosed with CAP, optimal management should be based on the site of care, the severity of CAP, the resistance profiles of bacteria, and the pharmacokinetic-pharmacodynamic targets that ensure bacterial eradication. Site of Care Site of care in patients with CAP impacts the overall cost of treatment, the intensity of diagnostic testing, and options for empiric antimicrobial selection. The decision to admit a patient with CAP is based on (a) mortality prediction rules, such as the PORT (Pneumonia Outcomes Research Team) Severity Index (PSI) score or CURB-65 (Confusion, Urea concentration, Respiratory rate, Blood pressure, and age > 65), (b) social circumstances of the patient, and (c) co-existing conditions. Hospitalization. Hospitalization should be considered when (a) patients have pre-existing conditions that may compromise the safety of home care, (b) patients have hypoxemia, (c) patients are unable to take oral medications, or (d) psychosocial factors can