Study links antibiotic overuse to diagnostic mistakes

Diagnostic errors may be one overlooked factor in the battle to drive down the unnecessary use of antibiotics, according to a study released Monday by the Minneapolis VA Medical Center. An analysis found that in nearly every case where a patient's initial diagnosis was undetermined—listed as a symptom rather than a disease—or was later found to be totally incorrect, the patient was given a course of antibiotics they didn't need.

Despite concerted national efforts over the past few years to rein in the over-prescribing of antibiotics, “There is still a huge amount of room for improvement,” said lead study author Dr. Gregory Filice, an infectious disease specialist with the Minneapolis VA Health Care System. “And if you look at overall hospital antibiotic use, diagnostic errors are likely a big part of it,” he said.

Filice and a team of researchers evaluated 500 randomly selected VA inpatients who received antibiotics between October 2007 and September 2008. Four physicians who were board-certified in internal medicine and infectious diseases judged the accuracy of the initial diagnoses.

Reviewers came to different diagnostic conclusions in more than a third of the cases, the review found. And when there was disagreement, patients were more likely to be prescribed unnecessary antimicrobial drugs.

Of 209 cases in which the initial diagnosis was inconclusive or ultimately found to be incorrect by the reviewers, 95% of the antimicrobial courses were inappropriate. On the other hand, of the 291 cases in which the initial diagnosis was correct, only 38% of the antimicrobial courses were inappropriate. Findings by the Minneapolis VA Medical Center were published Monday in the journal Infection Control and Hospital Epidemiology.

There has been increased attention on the overprescription of antimicrobials due to the global surge in drug-resistant bacteria and superbugs like methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae. An estimated 2 million people are sickened and 23,000 die every year from drug-resistant infections, a problem so prevalent it was recently deemed “a threat to national security” by the Obama administration.

The problem has persisted despite the efforts to fight it. Campaigns may have greater impact if designed to include decision supports that help providers make accurate diagnoses in the first place, suggests Filice.

He says the VA is considering a four-tiered strategy that includes having pharmacists review the electronic health data when a prescription for an antibiotic is submitted and requiring physicians to include an actual diagnosis when making the prescription. “It's so easy to start an antibiotic, but that will force them to think carefully about the decision,” according to Filice, who says they are often prescribed out of habit.

The strategy also includes targeted diagnostic education for when to prescribe antibiotics and tools to help in the diagnostic process. In a Modern Healthcare post earlier this year, a hospital safety expert said diagnostic errors, which are one of the most common yet overlooked safety problems, account for about 1 in 6 incidents of system-induced patient harm. An IOM report anticipated this year is expected to raise a red flag on the scope of the problem in the United States.