New research from Brigham and Women’s Hospital (BWH) in Boston, MA, finds high rates of unnecessary prescribing of antibiotics for sore throats and bronchitis across the US.

The researchers, who report their study in the latest online issue of JAMA Internal Medicine, also presented their findings at the infectious diseases meeting, IDWeek 2013 in San Francisco on October 3rd.

They found a large discrepancy between numbers of outpatient visits requiring antibiotics and the national prescribing rates for the drugs.

This is despite the fact that for decades, the US Centers for Disease Control and Prevention (CDC) and other bodies have been pushing to reduce inappropriate prescribing of antibiotics.

Antibiotics are a class of drugs used to treat, and in some cases prevent, infections caused by bacteria. They do not work against viruses, and in fact, taking antibiotics for viral infections can do more harm than good, says the CDC.

Unnecessary prescribing and overuse of antibiotics has led to a surge in superbugs, bacteria that are increasingly resistant to antibiotics.

Senior author Dr. Jeffrey A. Linder, a physician and researcher at BWH’s Division of General Medicine and Primary Care, explains:

“We know that antibiotic prescribing, particularly to patients who are not likely to benefit from it, increases the prevalence of antibiotic-resistant bacteria, a growing concern both here in the United States and around the world.”

Lead author Dr. Michael L. Barnett, a clinical fellow in medicine at Harvard Medical School, with which BWH is affiliated, says:

In addition to contributing to the prevalence of antibiotic resistant bacteria, unnecessary use of antibiotics also adds financial cost to the health care system and causes adverse effects for those taking the medication.”

Dr. Linder says their findings show that while only 10% of adults with sore throat have strep, the only common cause of sore throat that needs antibiotics, the US national prescribing rate of antibiotics for adults with sore throat has stayed at 60%.”

And for acute bronchitis, he says the prescribing rate for the correct antibiotic should be near 0%, yet they found the national antibiotic prescribing rate was 73%.

For the study, the researchers consulted nationally representative surveys covering 1996 to 2010 of ambulatory care in the US, and they looked for changes in prescribing rates for antibiotics for adults with sore throat and acute bronchitis.

The data they examined covered around 39 million visits for acute bronchitis and 92 million for sore throat by adults attending primary care centers or hospital emergency departments.

Their analysis showed while visits for sore throats fell from 7.5% of primary care visits in 1996 to 4.3% in 2010, and there was no change in percentage of emergency department visits over the same period, the overall national rate of antibiotic prescribing remained unchanged at 60% of visits.

They also found that prescriptions for penicillin, the recommended antibiotic for strep throat, did not vary and stayed at 9% over the 14-year period.

Meanwhile, prescriptions for a more expensive antibiotic, azithromycin, “increased from below the threshold of reliable measurement in the 1997-1998 measurement period to 15% of visits in the 2009-2010 period,” write the authors.

They note that “despite decades of effort, we found only incremental improvement in antibiotic prescribing for adults making a visit with sore throat.”

The number of visits for acute bronchitis rose from 1.1 million in 1996 to 3.4 million in 2010.

The researchers also found that emergency room antibiotic prescribing increased from a rate of 69% of visits to 73% over the same period.

Dr. Barnett says most sore throats and cases of acute bronchitis do not require a visit to the doctor, and should be treated with rest and fluids.

Grants from the National Institutes of Health, the National Institute of Allergy and Infectious Diseases, and the Agency for Healthcare Research and Quality helped support some of the work for this study.

In a recent landmark report, the CDC gives the first snapshot of how antibiotic resistance threatens US health and proposes four core actions to tackle the growing problem, including the need to shift toward more sparing and judicious use of antibiotics.