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.