Urinalysis Overuse Inflates Antibiotic Orders for Elderly

Marcia Frellick

August 20, 2015

Urinalysis was ordered for more than half of elderly patients on admission to an emergency department at a large tertiary care center, even though most lacked an appropriate clinical indication, according to findings in a new study.

Urinalysis has excellent predictability for ruling out urinary tract infection (UTI); however, a positive result is less informative because it occurs in as many as 90% of asymptomatic elderly patients, the study authors say.

The results were published online August 17 in JAMA Internal Medicine.

Penny Yin, MD, from the Department of Medicine, University of Toronto, Ontario, Canada, and colleagues also found that positive urinalysis results can introduce cognitive biases in favor of a UTI diagnosis, even when patients lack accepted criteria. Positive results from these asymptomatic patients significantly increased their odds of receiving additional low-value care, including urine cultures and antibiotics for asymptomatic pyuria or bacteriuria.

Of 403 general medicine patients with a median age of 79 years, 250 patients (62.0%; 95% confidence interval [CI], 57.3% - 66.7%) underwent urinalysis on admission at the discretion of the emergency department or general medicine physicians. The majority of these patients, 211 (84.4%; 95% CI, 79.9% - 88.9%]) lacked symptoms of UTI, and 198 (79.2%; 95% CI, 74.2% - 84.2%) lacked UTI and acute kidney injury.

Each patient in the study was assessed within 24 hours for indications calling for urinalysis, including symptoms of UTI based on guidelines for patients with and without urinary catheters or acute kidney injury, which researchers defined as a twofold rise in creatinine levels in the blood.

Positive urinalysis results were associated with increased probability of urine culture orders (P < .001) and antibiotic prescription (P < .001) among asymptomatic patients. After controlling for other variables, only multiple comorbidities were significantly linked with urinalysis orders without indication (odds ratio, 5.3; 95% CI, 2.5 - 11.0; P < .001).

Conversely, appropriate orders among symptomatic patients were effective in excluding UTI, thus sparing antibiotics.

The findings show the harm of too many routine urinalysis orders at admission. "Limiting indiscriminate [urinalysis] ordering has the potential to improve [urine culture] and antimicrobial prescribing practices among [general medicine] patients," the authors conclude.

One limitation of the study is that it was performed at only one center, and prescribing patterns may be different elsewhere.

The authors have disclosed no relevant financial relationships.

JAMA. Published online August 17, 2015. Abstract


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