A team of researchers establishing baseline data on antibiotic use by the Veterans Administration (VA) healthcare system in Pittsburgh found that about 75% of all antibiotic prescriptions were inappropriate, meaning they were either not indicated or were used for a duration that's not recommended.
"We found quite a bit of overprescribing," said Nathan R. Shively, MD, the Medical Director of the Antimicrobial Stewardship Program at Allegheny Valley Hospital, and lead author of the study, which appeared yesterday in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.
Study included chart review
The study, which took place over 12 months, looked at prescribing information, medical records, and charts of 40,734 patients, who were written 3,880 acute antibiotic prescriptions by 76 primary care providers (PCPs). The median antibiotic index was 84 antibiotic prescriptions per 1,000 patients per year.
Antibiotics were not indicated in 49.7% of cases in which they were written, including 74% of prescriptions written for acute respiratory tract infections, and 30% of those written for urinary tract infections. Those infections, along with skin and soft tissue infections, were the most common illnesses treated with antibiotics.
In 12.3% (37/300) of cases, an antibiotic was indicated, but the prescribed agent was guideline discordant, meaning the wrong drug was used, and in another 14% of cases, the antibiotic was given for too long a time. Overall, 76% of the reviewed prescriptions were considered inappropriate.
Ciprofloxacin and azithromycin were the antibiotics most likely to be prescribed inappropriately. Azithromycin was the most commonly prescribed drug, used in 25.8% of cases, followed by amoxicillin-clavulanate (13.3%), doxycycline (12.4%), amoxicillin (11%), trimethoprim-sulfamethoxazole (10.6%), and cephalexin (7.9%). Fluoroquinolones accounted for 11% of prescriptions (ciprofloxacin, 7.6%; moxifloxacin, 2%; levofloxacin, 1.4%). Other agents represented 8% of prescriptions.
VA may be canary in the coal mine
Shivley told CIDRAP News the rates of overprescribing in the VA system were much higher than national estimates. Current estimates suggest 30% of antibiotics prescribed in the ambulatory care setting are inappropriate.
"But the way annual estimates are presented, I think they are underestimating the overuse of antibiotics. It's not that the VA is alone in over prescribing," he said. In that way, the VA may be a better picture of antibiotic use in the US than other national studies.
Shivley said the rates were higher because this study included chart review and took into account duration of use for each prescription.
Jul 2 Antimicrob Agents Chemother abstract