Published in the May 2007 issue of Today’s Hospitalist.
New guidelines on the diagnosis and treatment of community-acquired pneumonia (CAP) contain some welcome news for hospitalists. Not only do the guidelines tighten the definition of this common disease, but they also relieve what some say is pressure on physicians to overprescribe antibiotics.
The guidelines, which were released earlier this year by the Infectious Diseases Society of America and the American Thoracic Society, change the definition of CAP by stating that patients must not only have signs and symptoms of pneumonia, but must show an infiltrate on a chest X-ray.
That new definition is significant because it should help reduce confusion about exactly who has CAP. Experts also hope the change will help lower the number of patients who receive antibiotics inappropriately.
But the guidelines make another recommendation, one that may go even farther to reduce unnecessary antibiotic use: They do away with the recommendation that patients who have CAP need to receive an antibiotic within four hours of their arrival at the hospital.
Quality measures used by payers like Medicare are currently tracking how quickly CAP patients receive antibiotics, a development that many physicians complain has led to the overuse of antibiotics. If a patient might have pneumonia, some say, hospitals are urging their physicians to prescribe antibiotics first and ask questions later, lest they fall short on Medicare’s quality measure for pneumonia.
Avoiding the rush to prescribe
Instead of sticking with the current four-hour window for the initiation of antibiotic therapy, the guidelines recommend that CAP patients receive antibiotics before they leave the ER.
"Antibiotics should not be applied to meet a four-hour rule," says Antonio Anzueto, MD, a member of the committee that authored the guidelines. In creating the guidelines, he says, the committee reviewed conclusive data from the CDC that patients without CAP were receiving antibiotics inappropriately.
"What was happening was that a lot of people who didn’t need antibiotics were receiving the drug," Dr. Anzueto says. "You walk into an ER coughing, and you get a shot before anyone even asks you a question."
By stating that patients have CAP only if they show an infiltrate on a chest film, the guidelines should take some pressure off physicians to prescribe antibiotics before all the data are in. Dr. Anzueto says the change will also eliminate widespread confusion about exactly who has “and who does not have “the disease.
"In the past, there has been a lot of discussion about how to treat the patient who has fever but doesn’t show an infiltrate until three days later," explains Dr. Anzueto, who is professor of medicine at the University of Texas Health Science Center in San Antonio. He notes that the issue is particularly relevant for hospitalists, because infiltrates often appear in inpatients after they’ve received IV fluids for a few days.
But for patients who have no infiltrate “and therefore do not have community-acquired pneumonia “how do the guidelines expect physicians to proceed? Dr. Anzueto says that other diagnoses need to be considered.
"The guidelines strongly recommend that you look for something else," he points out. A good place to start, he adds, is to look for influenza A, influenza B, respiratory syncytial virus and the legionella antigen.
Making the diagnosis
The guidelines recommend, for example, blood and sputum cultures for CAP patients, as well as urinary antigen assays. Dr. Anzueto also says there is strong evidence for conducting viral rapid assays in patients with upper and lower respiratory conditions.
He notes that in one recent study, researchers found positive blood cultures in inpatients with CAP about 15% of the time. The tests are recommended in inpatients only, he points out, a fact that should be of particular interest to hospitalists.
Besides clarifying a diagnosis of CAP, these diagnostic tests should also help thwart the development of antimicrobial resistance. "In view of changes in the resistance patterns of pathogens and changes in the pathogens themselves," Dr. Anzueto says, "the only way to understand what happens in hospitals is to have microbiological assessments."
The definition of CAP isn’t the only thing that will be new to hospitalists. The guidelines also recommend using a tool that few will likely have heard about: CURB-65.
Dr. Anzueto says the beauty of the CURB-65 criteria, which were developed by the British Thoracic Society as a severity scoring tool, is their simplicity. In the criteria, "C" stands for confusion, or changes in mental status; "U" stands for uremia, referring to signs of end-stage organ damage; "R" stands for a respiratory rate of more than 30 breaths per minute; and "B" stands for blood pressure (hypotension).
Patients receive one point for each category in which they’re having trouble, and one point if they’re 65 or older. Patients with CURB-65 scores greater than 2 should receive more intensive treatment, either in a monitored area such as intermediate care or the ICU.
Dr. Anzueto says the tool will help hospitalists decide where to hospitalize CAP patients. "If patients have more than two points on the CURB-65 scale," he explains, "they should go to the ICU or an intermediate care bed, not the floor."
The CURB-65 criteria are particularly important, he adds, because studies have shown that mortality rates in very sick CAP patients can be between 15% and 20%. In addition, he notes that studies have shown that up to 30% of CAP patients admitted to the ICU come from the wards “and probably should have been sent directly to the ICU. By using the tool, he says, hospitalists may be able to reduce CAP morbidity and mortality.
When it comes to treating inpatients with CAP, the guidelines recommend either combination therapy that pairs a beta-lactam with a macrolide, or monotherapy that consists of a respiratory fluoroquinolone.
But when push comes to shove, Dr. Anzueto says, the guidelines say that a respiratory fluoroquinolone “gemifloxicin or moxifloxicin “is often going to be the drug of choice.
At the same time, the guidelines make it clear that not all fluoroquinolones are the same. "The committee believed pretty strongly that there is a separation between the fluoroquinolones," Dr. Anzueto says. "The one-drug-fits-all approach is not appropriate given the microbiological sensitivities."
Because the guidelines call specifically for respiratory fluoroquinolones to treat CAP, Dr. Anzueto says he expects to see a greater use of moxifloxicin and gemifloxicin. He thinks that levofloxacin will be used more for urinary tract infections, and that ciprofloxacin will be used more for gram negatives.
Dr. Anzueto does note, however, that the guidelines’ emphasis on choosing the right fluoroquinolone may cause problems for physicians at the many hospitals that currently have only one fluoroquinolone on their formulary. He notes that many formularies, for example, pair moxifloxicin and ciprofloxacin, largely because oral generic ciprofloxacin is so inexpensive.
On the issue of combination vs. monotherapy for CAP, the guidelines come down slightly in favor of monotherapy with fluoroquinolone. Dr. Anzueto says that three recent studies show that fluoroquinolones are probably more effective than a beta-lactam in combination with a macrolide.
According to Dr. Anzueto, there are clear benefits to using a fluoroquinolone: "You’re going to see more rapid clinical improvement, it’s going to allow you to switch your patients to oral therapy sooner, and you may be able to shorten the patient’s length of stay."
He notes, however, that there are also some potential downsides to monotherapy. The primary concern is that using the same drug day in, day out will help foster antimicrobial resistance.
"One of the things we all struggle with as clinicians, especially in hospital practice, is treating all our patients with the same antibiotic all the time," Dr. Anzueto says. "At the end of the day, we may foster the beginning of resistance."
Recognizing those concerns, the guidelines suggest considering alternating therapies. "For one patient, you use combination therapy, and for another you use only a fluoroquinolone," Dr. Anzueto says. "One week, you use one therapy, and the next week you use something different."
Edward Doyle is Editor of Today’s Hospitalist.