Inappropriate antimicrobial therapy linked to diagnostic errors

PHILADELPHIA — Diagnostic errors often were the cause of inappropriate antimicrobial therapy among inpatients, but even among accurate diagnoses, there still is room for improvement in antimicrobial prescribing, according to data presented at IDWeek 2014.

“We found that 69% of inappropriate antimicrobial courses were attributable to problems with the initial diagnoses,” Gregory A. Filice, MD, of the division of infectious disease at the University of Minnesota and of the Minneapolis Veterans Affairs Healthcare System, said during his presentation. “Diagnostic accuracy has a tremendous impact on antimicrobial appropriateness and types of antimicrobial errors are related to the accuracy of diagnoses.”

Gregory A. Filice

Filice and colleagues evaluated antimicrobial courses given to 500 randomly selected inpatients in the VA hospital from 2007 to 2008, including information about the index condition leading to the antimicrobial use, the initial diagnosis of the condition and the antimicrobial agents used. Two masked infectious disease physicians reviewed each case and classified whether the initial diagnosis was correct, uncertain, not correct or a sign or symptom of infection rather than a syndrome or disease. They also determined whether the antimicrobial course was appropriate.

The reviewers determined that 58% of the initial provider diagnoses were correct. Accuracy was variable for each diagnosis, however, and ranged from 90% for bacteremia or sepsis to 27% for cystitis, pyelonephritis or urosepsis. Among the incorrect diagnoses, 6% were classified as a sign or symptom, rather than a syndrome or disease, 31% were not correct and 4% were indeterminate.

Overall, the reviewers classified that 38% of the antimicrobial courses were appropriate, but appropriateness varied by diagnostic accuracy. When the diagnoses were correct, 62% of the antimicrobial courses were appropriate, compared with 4% for incorrect diagnoses, 7% for signs and symptoms and 9% for indeterminate diagnoses.

Among the 111 cases with correct diagnoses, but inappropriate antimicrobials, 73% involved the wrong antimicrobial drug, 39% involved wrong duration, 5% involved wrong dose and antimicrobial therapy was not indicated for 4%. Some cases involved more than one error. Among the 198 cases with incorrect or uncertain diagnoses or signs and symptoms and inappropriate antimicrobials, treatment was not indicated in 86% of cases. Another 16% involved wrong antimicrobials, 7% involved incorrect duration and 1% involved wrong dose.

“Future research should elucidate mechanisms of diagnostic errors that affect antimicrobial prescribing,” Filice said. “Antimicrobial stewardship programs should help providers make accurate initial diagnoses and help providers know when they can safely withhold antimicrobial therapy.” — by Emily Shafer

For more information:

Filice GA. Abstract 609. Presented at: IDWeek 2014; Oct. 8-12; Philadelphia

Disclosure: Filice reports no relevant financial disclosures.