adults represent an important and growing demographic in emergency
departments (ED) across the country, with urinary tract infections
(UTIs) being one of the leading causes for ED visits. In fact, UTIs,
which can progress to serious health concerns, are the fourth most
common diagnosis in women over age 65. But a new study at Rhode Island
Hospital has found that many such women receive treatment for a UTI, but
have no firm evidence of such an infection, resulting in the prescribing
of unnecessary antibiotics. The study is published online in advance of
print in the Journal of the American Geriatrics Society.
The study, conducted by Leonard Mermel, DO, medical director of the
department of epidemiology and infection control at Rhode Island
Hospital, and his colleagues found that collection of urine to rule in,
or rule out, a UTI in this patient population is best done by inserting
a temporary catheter into the bladder to collect the specimen rather
than collecting urine by the so-called ‘clean catch’ method. Researchers
found the latter method more often leads to contamination of the urine
“Our study had two important findings: elderly women presenting to
emergency departments are often presumed to have a UTI and are treated
as such, despite a lack of supportive evidence, and that collecting
urine by the so-called ‘clean catch’ method more often leads to
contamination of the urine specimen,” Mermel said.
Often, a clinician in an emergency department will base a UTI diagnosis
in great part on the patient’s symptoms, particularly in older women for
whom UTIs are common. While the patient will have completed a
urinalysis, often by clean catch, the results are typically not
available during the patient’s visit to the emergency department.
Therefore, the clinician will often prescribe antibiotics to treat the
UTI, despite the fact that a diagnosis is not definitive.
The researchers studied the medical records of 153 older women who were
diagnosed with a UTI during a visit to an emergency department. They
found that only 57 percent of the 153 women who were given a diagnosis
of a UTI actually had urine cultures that confirmed the diagnosis. Of
the remaining patients whose urine studies did not confirm a UTI, 95
percent were administered or prescribed antibiotics in the ED.
Inappropriate antibiotic use in the ED setting for presumed UTIs has
been associated with antimicrobial resistance and undesired side-effects
as antibiotics are the second leading class of drugs to cause adverse
events, such as diarrhea due to Clostridium difficile (C-diff), in
patients over age 65.
“Ultimately, we found that a large proportion of older women were
overdiagnosed and overtreated for UTI,” Mermel said. “Physicians
assessing such patients cannot rely on non-specific symptoms such as
confusion to confirm a diagnosis of UTI. More widespread use of straight
catheterization in this patient population may reduce false-positive
results of urine studies, thereby reducing unnecessary antibiotic
exposure and may prompt clinicians to assess these patients for other
etiologies to explain their symptoms.”
Researchers said that further study must be conducted to determine if
straight catheterization is truly the better method for obtaining urine
for culture in this patient population, and to identify other strategies
that will improve the accuracy of the diagnosis.
The study was funded by a grant from
the Reynolds Foundation, awarded to co-author Lesley Gordon, MS, of the
Alpert Medical School. Mermel’s principal affiliation is Rhode Island
Hospital, a member hospital of the Lifespan health system in Rhode
Island. He also has an academic appointment at The Warren Alpert Medical
School of Brown University, department of epidemiology and infection
control. Other researchers involved in the study are Michael J. Waxman,
MD, Albany Medical College, NY; and Luna Ragsdale, MD, MPH, Duke
University, Durham, NC.