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New treatment guidelines for community-acquired pneumonia available
Therapy should be tailored to specific patients
The Infectious Diseases Society of America (IDSA) has updated its treatment guidelines for community-acquired pneumonia (CAP) in immunocompetent adults, just in time for a season that is expected to have higher-than-normal cases of lung disease.
IDSA, based in Alexandria, VA, has published previous versions of its guidelines in 1998 and 2000. In the most recent update, the committee that was charged with revising the guidelines was troubled by the increasing resistance of bacterial infections to antimicrobial therapy.
"One of our concerns is that if the quinolones keep being misused at the rate that they currently are, this class of drugs may become useless in five to 10 years," says Lionel A. Mandell, MD, FRCPC, professor of medicine and chief of the division of Infectious Diseases at McMaster University in Hamilton, Ontario, Canada. He is a member of the committee and the lead author of the guidelines.
The committee tried to put quinolones in their proper perspective, he says. "There is a role in macrolides [in this treatment], as well," he says.
Past guidelines included more of an overview of CAP treatment, Mandell says. In contrast, the new ones focus more on new areas of inter-est, such as updated recommendations and special populations and circumstances such as severe acute respiratory syndrome (SARS) and bioterrorism.
Decide where to treat the patient
One important aspect the committee first considered was the importance of the selection of the initial site of treatment of patients with CAP, whether it be the home or the hospital. (This decision often is made in the emergency department, the entry point for 75% of the 1 million annual pneumonia admissions in the United States, the committee says.) This selection often determines the selection and route of administration of antibiotic agents, intensity of medical observation, and use of medical resources.
The committee follows the suggestion in recent literature that the initial site of treatment decision be selected using a systematic three-step process:
• Step 1 involves assessment of pre-existing conditions that compromise the safety of home care, such as severe hemodynamic instability, active coexisting conditions that require hospitalization, acute hypoxemia or chronic oxygen de-pendency, and inability to take oral medications.
• Step 2 involves calculation of the Pneumonia PORT Severity Index (PSI), in which patients are stratified into five severity classes by means of a two-step process:
—Patients must meet the following criteria for class I: Age under 50 years, with none of five comorbid conditions (i.e., neoplastic disease, liver disease, congestive heart failure, cerebrovascular disease, and renal disease), normal or only mildly deranged vital signs, and normal mental status.
—Patients not assigned to risk class I are stratified into classes II-V on the basis of points assigned for three demographic variables (age, sex, and nursing home residency), the five comorbid conditions listed above, five physical examination results (pulse, respiratory rate, systolic blood pressure, temperature, and altered mental status), and seven laboratory and/or radiographic results (arterial pH, blood urea nitrogen level, sodium level, glucose level, hematocrit, hypoxemia by O2 saturation, and pleural effusion on baseline radiograph).
Hospitalization usually is not required for classes I-III. The patient usually will require hospitalization for classes IV and V.
Social factors, such as outpatient support mechanisms and probability of adherence to treatment, are not included in this assessment, the committee says.
• Step 3 involves clinical judgment regarding the overall health of the patient and the suitability for home care. Mitigating factors for step 3 include frail physical condition, severe social or psychiatric problems compromising home care (including a history of substance abuse), and an unstable living situation or homelessness.
Committee suggests new initial empiric therapy
The committee also introduced new diagnostic and management strategies, including suggestions for initial empiric therapy for CAP. For example, the main treatment table in the former guidelines for outpatients primarily recommended macrolides, quinolones, and doxycycline, Mandell says. Now the table is more explanatory and categorizes the treatment recommendation for outpatients by modifying factors, such as someone who is perfectly well otherwise; those with comorbidity, such as chronic obstructive pulmonary disease, diabetes, or cancer; or suspected aspiration. In addition, treatment depends upon whether patients have recently taken antibiotics.
"We didn’t have those main categories previously," Mandell says. "[In these guidelines,] we tried to be more careful and detailed in explaining when antibiotics should be used." The guidelines, which were published in the Dec. 1 issue of the journal Clinical Infectious Diseases and are available on-line at www.idsociety.org, place these treatment recommendations in an easy-to-read table, and then list the advantages and disadvantages for this empiric antibacterial selection in another table. Pharmacists as well as physicians should become familiar with the treatment tables, Mandell says.
Start therapy earlier
Another new recommendation in the guidelines addresses the issue of when antibiotic therapy should be initiated for patients with acute pneumonia. The previous IDSA guidelines recommended initial administration within eight hours after arrival of the patient at the hospital. This was based on a retrospective analysis of Medicare hospitalizations for pneumonia in 1994 and 1995.
A more recent analysis of Medicare hospitalizations, however, demonstrated an association between initiation of antimicrobial therapy within four hours after arrival and improved outcomes. Based on these findings, the committee supports the four-hour initiation of the therapy patients requiring hospitalization for CAP.
In addition, the committee recommends that patients who smoke and who are hospitalized with CAP should have the goal of stopping cigarette use. Besides its association with morbidity and mortality, smoking is associated with a substantial risk of pneumococcal bacteremia and a risk for Legionella infection. The committee suggests that patients try to stop smoking while still in the hospital.
Feedback takes both sides
Mandell praises the excellent feedback the committee has received internally from IDSA. He has received some interesting responses, however, as other individuals read the guidelines for the first time. "When they first went on the Internet, one person wrote to us and said they were using quinolones too much. Another person said they were using macrolides too much. We figured that if we were getting it from both sides, we were probably getting it right."