Seniors in the U.S. are prescribed at least one antibiotic each every year, on average - but the rate of prescribing varies quite a bit across the country, a new study finds.
In some parts of the country, seniors averaged less than one antibiotic prescription per year, while in others, they received between one and two per year, according to a report in Archives of Internal Medicine.
Records from Medicare, the government-run insurance program for the elderly, showed older adults in the South were prescribed more antibiotics than seniors living elsewhere in the country and that prescribing everywhere went up in the winter months.
That variation suggests overuse of antibiotics in some cases - an important public health issue because both normal and inappropriate use of the drugs can lead to bacterial resistance, which makes future infections extra difficult to treat.
Researchers found that from 2007 through 2009, 21 percent of Southern seniors used an antibiotic during each three-month period, compared to 17 percent of those living in the West.
The South had the highest use of every subclass of antibiotics, but differences were especially driven by use of quinolones and macrolides, which are "broad spectrum" antibiotics. That means they are effective against a wide range of bacteria. It also means resistance to them is especially worrisome.
"Once you get resistance to those broad spectrum antibiotics, next time you have anything where you really need that, it's not going to be as effective," said Yuting Zhang, the study's lead author from the University of Pittsburgh.
Consistent with that pattern, antibiotic resistance rates were highest in the South, Zhang told Reuters Health.
The researchers said it's hard to know the appropriate level of antibiotic prescribing because they would need detailed information from patients' medical records on their specific diagnoses.
And in some cases, it's not totally clear to doctors whether the drugs will help patients get better sooner, even when they're in the exam room.
"We don't have the perfect test that says, ‘Yes you need antibiotics; no you don't need antibiotics,'" said Dr. Ralph Gonzales from the University of California, San Francisco, who co-wrote a commentary accompanying the study.
But, Zhang added, patients in the South more often had conditions that typically don't require antibiotics - such as viral respiratory infections - and these were possibly driving the increased prescribing.
In a research letter published alongside her study, another group of researchers found more than 80 percent of adults with a sinus infection between 2000 and 2009 were prescribed an antibiotic.
Broad spectrum antibiotics were often used in those cases as well.
That is "despite mounting evidence that the benefits of antibiotic treatment for sinusitis are limited," Dr. Tarayn Fairlie of the Centers for Disease Control and Prevention and colleagues wrote.
Zhang said one thing people can do to prevent the overuse of antibiotics and resistance is to avoid asking their doctor for the drugs when they may not be needed.
"A strong reason for giving antibiotics has less to do with the clinical manifestations and more to do with patient expectations and requests for antibiotics," Gonzales told Reuters Health.
He said researchers have made some headway in encouraging appropriate use of the drugs, but it can be hard to get busy doctors, hospitals and insurance companies all on board.
"We need to start thinking of different ways where we can really change the culture around antibiotics," Gonzales said.