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Modified urine culture reporting reduces treatment for asymptomatic bacteriuria by 27%
Withholding certain lab results from physicians reduced inappropriate antibiotic treatment of patients with asymptomatic bacteriuria, or ASB, by almost 30% in a small proof-of-concept study conducted in two Canadian hospitals.
According to Peter Daley, MD, MSc, associate professor of infectious diseases at Memorial University in St. John’s, Newfoundland, and colleagues, treating ASB with antibiotics has not been shown to prevent symptomatic urinary tract infection (UTI), complications or death but instead is associated with an increased rate of adverse events.
Writing in Infection Control & Hospital Epidemiology, they said previous studies have shown the benefits of partially withholding lab results from physicians in certain situations. One intervention that kept positive culture results from physicians, unless they were prompted by patient symptoms to ask for them, reduced unnecessary treatment of ASB by 36%.
Daley and colleagues hypothesized that modified reporting of positive urine cultures among inpatients would reduce unnecessary treatment of ASB without increasing untreated UTI, pyelonephritis, bacteremia or death. They designed a randomized, parallel, unblinded superiority trial comparing two methods of reporting positive urine cultures to physicians at two hospitals in St. John’s:
standard lab reports, which included bacterial count, bacterial identification and antibiotic susceptibility;
and modified reports, in which physicians were informed that significant bacteria growth was detected, but bacteria identification and susceptibility information were withheld unless requested.
The modified reports included a note that said: “This POSITIVE urine culture may represent asymptomatic bacteriuria or urinary tract infection. If urinary tract infection is suspected clinically, please call the microbiology laboratory ... or the microbiology technologist on-call ... for identification and susceptibility results.” Reports were immediately provided to physicians who requested them.
The primary efficacy outcome was the proportion of appropriate antibiotic treatment prescribed by the physicians, with appropriate treatment being defined as treated UTIs plus untreated ASB.
According to Daley and colleagues, in the intent-to-treat analysis, the proportion of appropriate treatment was 80% (44 of 55 patients) in the modified arm vs. 52.7% (29 of 55 patients) in the standard arm, for an absolute difference of 27.3% (RR = 0.42; P = .002).
“Our design is a proof-of-concept study that requires additional verification trials before implementation,” Daley and colleagues wrote. “It would be impractical for laboratories to manually screen all inpatient urine specimens using our inclusion criteria, although automated eligibility screening may be possible.”
They said guidelines suggest that laboratories take a more active role in antibiotic stewardship and that modified reporting is a “simple, low-cost, sustainable intervention.”
“Future possible laboratory interventions could include physician order entry or rejection of urine collected for inappropriate reasons. Whether physician urine ordering would be more appropriate compared to nurse ordering remains a question for further study,” they wrote. – by Gerard Gallagher
Disclosures: The authors report no relevant financial disclosures.