Study finds wrong antibiotics often given for common infections

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Throat exam

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Only half of the patients diagnosed as having one of three common bacterial infections are receiving the recommended first-line antibiotic treatment, according to new research from the Centers for Disease Control and Prevention (CDC) and the Pew Charitable Trusts.

The findings also come with recommendations from a Pew panel on which outpatients should get first-line antibiotics.

The research, published today in JAMA Internal Medicine, found that, of the more than 44 million patients who receive outpatient antibiotic prescriptions for sinus infections, middle-ear infections, and pharyngitis (sore throat) each year, only 52% receive the recommended first-line antibiotics such as penicillin or amoxicillin.

Instead, they are being treated with broader spectrum antibiotics like azithromycin, a finding experts say is problematic on several levels.

Narrow-spectrum drugs like penicillin and amoxicillin are recommended as first-line therapy for sinus infections, middle-ear infections, and pharyngitis because they are the best treatment available. And one of the reasons they are better than macrolides like azithromycin for sinus and middle-ear infections is because of high rates of resistance to macrolides among Streptococcus pneumoniae, the most common bacterial cause of these infections.

"We believe the first-line therapy is most likely the best therapy for the patient," study author Lauri Hicks, DO, director of the CDC's Office of Antibiotic Stewardship, told CIDRAP News. "So we have concerns about this from a patient safety perspective."

But beyond that, Hicks added, using broad-spectrum antibiotics that cover more types of bacteria can potentially fuel greater resistance to those drugs. And that could endanger treatment of more serious infections.

"When we're using those broad-spectrum agents for these conditions, we're potentially losing the ability to use them in the more serious situations where we really need them," Hicks said.

Antibiotic selection

This is the second report published by Pew and the CDC on outpatient antibiotic prescribing. The first, published in May, found that at least 30% of antibiotic prescriptions in outpatient settings are unnecessary—such as when antibiotics are prescribed for viral illnesses like the common cold. This study looked at antibiotic selection.

The authors of the study focused on sinus infections, middle-ear infections, and pharyngitis because those three conditions account for nearly 30% of the antibiotics prescribed in outpatient settings—which includes doctor's offices, emergency department, and hospital specialty clinics (but not urgent care clinics or retail clinics). Their analysis, based on US prescribing data from 2010 and 2011, distinguished between pediatric prescriptions and adult prescriptions.

A breakdown of the study's findings by type of infection shows that for sinus infections, only 52% of children were treated with the recommended antibiotic amoxicillin (or the alternative, amoxicillin with clavulanate), and only 37% of adults were prescribed these drugs. For pharyngitis, only 60% of kids and 37% of adults were treated with amoxicillin or penicillin. And only 67% of children received the proper antibiotics (amoxicillin or amoxicillin with clavulanate) for middle-ear infections, which rarely occur in adults.

Macrolides, the study found, were the most commonly prescribed non-first-line antibiotic.

"This tells us that there's a lot of room for improvement," co-author David Hyun, MD, a pediatrician and senior officer for Pew's antibiotic resistance project, told CIDRAP News. If there's a lot of deviation from the recommended treatment guidelines, Hyun explained, that means there's a higher chance that patients aren't being treated effectively. In addition, using broad-spectrum antibiotics can put patients at higher risk of adverse events, such as Clostridium difficile.

"When you don't use a first-line agent, the benefit-to-risk ratio changes," Hyun said.

Convenience and perception

Although the study does not explore the reasons providers are so frequently veering from the recommended treatments, both Hicks and Hyun have some ideas.

Hicks said the simplest explanation may be the convenience factor. For example, azithromycin is a once-a-day drug, while some of the first-line drugs need to be taken twice or even three times a day. But Hicks believes there's also a perception, shared by both provider and patient, that broader may be better, and that using drugs that cover more bacteria makes it less likely that something could be missed.

Hyun suggests there's also a social dynamic going between patients and doctors, where patient expectations—and how doctors perceive those expectations—are playing a role in antibiotic prescribing. "Physicians and providers feel, a lot of the time, that patients walk into their office with a certain level of expectation for antibiotics," Hyun said.

And that, along with the patient's previous experience, can have an impact on antibiotic selection. So if a patient has previously received a broad-spectrum antibiotic and it worked well, they'll probably ask for that same antibiotic again. "That can influence the prescriber," Hyun said.

Setting targets

In an accompanying report on the Pew Web site, a panel of experts set targets for improving the selection of antibiotic prescribing, based on an estimate of how much of the population should be getting first-line antibiotics for these conditions.

Their estimate, which took into account patients who might have allergies to first-line antibiotics or might not respond to the recommended therapy, was that at least 80% of outpatients should be getting first-line drugs. 

Hicks noted that this goal is very conservative, but said the panel "wanted to give doctors the benefit of the doubt," since there are cases where first-line antibiotics may not be the best choice.

Both Hicks and Hyun, who are members of the panel that set the targets, agree that reaching their goal will rely not only on better education for patients and providers but also on better communication between the two parties. That means patients need to be clear about their expectations, and doctors need to give patients as much information as they can about a given antibiotic and explain why the recommended antibiotics are the best treatment option.

"I think having an open dialogue is going to be very important," Hyun said.

See also:

Oct 24 JAMA Intern Med research letter

Oct 24 Pew Charitable Trusts report

May 3 Pew report

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