Healthcare providers throughout the country, especially in Mississippi and Alabama and the rest of the South, need targeted education to reduce the number of Medicare patients given antibiotics without indication.
That's the conclusion of a University of Pittsburgh-led report that found wide variation in antibiotic prescribing practices in outpatient settings by state and by region. It also found that when compared with studies of geographic variation in the use of all medications, regional variation in the use of antibiotics is significantly wider.
"In the south, 21% of seniors on average per quarter were using an antibiotic, and that's 4 percentage points higher than in the west, where usage was 17%," says Yuting Zhang, assistant professor of health economics and the study's principal investigator.
Rates were higher over the course of a year, according to data from Medicare Part D data for a three-year period ending Dec. 31, 2009. "The highest rate of any antibiotic use in 2009 was 56.8% in Mississippi, and second highest was 55.6% in Alabama," she said.
That compares with the lowest antibiotic use rates: 39.5% in Maine, 41.2% in New Hampshire, 41.4% in Wyoming, and 41.7% in Oregon.
Antibiotic spending varied as well, with most of the southern states and Texas in the highest bracket, of $38 to $47 per beneficiary, to most of the northeastern states, Montana, Oregon, Nevada, and Minnesota having the lowest rates, of $20–$27.
Zhang's report, which she says is the first to look at regional variation in antibiotic prescribing and cost, was published Monday in the Archives of Internal Medicine. Researchers from the University of California San Francisco and San Francisco Veterans Affairs Medical Centers were coauthors.
A separate article published by Tarayn Fairlie, MD, and other immunization experts at the Centers for Disease Control and Prevention says that 80% of outpatients diagnosed with acute sinusitis received an antibiotic, "despite mounting evidence that the benefits of antibiotic treatment for sinusitis are limited."
The statistics were collected from a sample of 4.3 million outpatient visits collected the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey between 2000 and 2009 and were not limited to a Medicare population.
"Changes in prescribing behavior of healthcare providers for sinusitis are urgently needed to improve healthcare quality and stem the rising tide of antibiotic resistance in the United States," they wrote.
Zhang says that in addition to unnecessarily raising the costs of care, inappropriate use of antibiotics, for example, to treat symptoms of a cold or a respiratory tract infection caused by a virus, give way to the emergence of resistant strains of bacteria.
"We know from previous studies that the rate of resistant strains in the south, especially, is higher than anywhere else in the country," she says.
Zhang explains that severity or type of illness does not account for the variation because adjustments were made for age, gender, race, poverty, and health status or condition.
"It may be patient or physician preference. Some patients may prefer to use antibiotics even if they're told by their doctors that they're not effective, and some physicians may just be more likely to prescribe antibiotics," even if the patient doesn't have a bacterial infection.
The variation may be explained, however, by specific Medicare Advantage health plan programs that include quality initiatives to reduce the use of antibiotics when they aren't necessary, she says. For example, in the West, a high number of Medicare beneficiaries are enrolled in Kaiser Permanente, which may have tighter institutional controls on the use of antibiotics than Medicare providers elsewhere.
From the report, high rates of antibiotic use were also found in North Carolina, West Virginia, Tennessee, Louisiana, Arkansas, Kansas and South Dakota.
Other states where antibiotic use was low include Washington, Montana, Wisconsin, Massachusetts, and Connecticut.
The report also looked at quarterly variation, with the highest rate of use during the winter. "Although rates of bacterial pneumonia were also higher in these months, so were the rates of acute nasopharyngitis and other acute respiratory tract infections. Because patients with these conditions are often prescribed antibiotics unnecessarily, it is likely that the rates of inappropriate use of antibiotics are also highest in the winter months," Zhang wrote.
She says overuse of antibiotics in Medicare patients is problematic because as they age, they are more likely to experience drug-drug interactions and adverse events resulting from the use of certain antibiotics. Additionally, overprescribing may provoke the emergence of resistant strains in seniors, taking away important ammunition that they may need for a subsequent illness.
In an invited commentary, Ralph Gonzales, MD, and colleagues at the University of California San Francisco, said that the two studies "are important reminders that the United States still has a long way to go in reducing antibiotic overuse" and "raise the question about why the problem of overprescribing exists."
They point out that numerous clinician-targeted programs, multi-agency task forces, and public health efforts have attempted to reduce overuse through education. Rates have gone down, they say, but not enough.
That's because there are significant obstacles to achieving behavior change. For starters, adverse events linked to use of antibiotics are rare events, and resistant strain emergence is not immediately noticed, they wrote.
If providers refuse patients demands for antibiotics when the drugs aren't warranted, the consequence may be the patient's "loss of trust in the clinician and clinicians may fear that patients may lose that trust in them."
"We need to find better ways to compel individuals and organizations to address the significance of the problem of antibiotic overuse and to increase the readiness for change and quality improvement of ambulatory practices in the United States," they wrote.