Most Patients With UTI Symptoms Receive Antibiotics, Yet Lack Evidence of Infection

A new study in the United Kingdom has uncovered that only one-third of patients who present to the emergency department with suspected urinary tract infections (UTI) have evidence of infection, yet the majority of patients receive antibiotics, contributing to the emergence of antimicrobial resistance.

According to the study team, led by Laura Shallcross, PhD, MBBS, MSc, of University College London, the concern over delaying treatment for severe UTIs indicate that clinicians have “a low threshold” for initiating antibiotics in the emergency department for patients with similar symptoms.

In an exclusive interview at the European Congress for Clinical Microbiology and Infectious Diseases ECCMID 2019, Contagion® spoke with Shallcross, the presenter of the poster, who explained the reasons why antibiotics are being prescribed in excess among these patients (see video).

For the study, the investigators sought to estimate the frequency of over-diagnosis of UTIs in the emergency department to, in turn, estimate the reduction in the burden of antimicrobial resistance by suspending treatment early for patients with no evidence of bacterial infection.

To accomplish this, the investigators launched a cohort study in a large teaching hospital. The team used electronic health records from patients who presented to the emergency department with suspected UTI syndromes, which were supplemented by medical note review.

All individuals with a urine sample submitted for microbiological culturing in the emergency department were eligible for inclusion. In total, the investigators randomly selected a subset of 1000 patients, 700 of whom were admitted to the hospital. The investigators described the clinical and demographic characteristics of the patient populations, by comparing diagnoses made by the emergency department physician to the clinical diagnostic based on symptoms, outcomes, and ICD-10 diagnostic codes. Lastly, consumption of antibiotics were estimated for these patients.

In total, 943 patients were included in the study, 671 participants (71%) were admitted to the hospital. Patient information indicates that 249 participants had an emergency department diagnosis of UTI syndromes including 56 cases of pyelonephritis, 42 cases of urosepsis, and 191 cases of lower UTI.

Records indicate that treatment with empirical antibiotics was prescribed for 173 (91%) of patients with an emergency department diagnosis of a lower UTI, but only 66 cases, (34.5%) actually had clinical evidence of a UTI.

ICD-10 diagnostic codes were available for 83 of the lower UTI cases, indicating that 34 participants (>40%) had a primary diagnostic code for a non-infectious condition, but were prescribed 8.1 antibiotic defined daily doses on average, and treated with antibiotics for a median of 7.5 days.

The investigators concluded that a focus on antibiotic review for patients who present to the emergency department and receive a diagnosis of suspected UTI syndromes could support reductions in inappropriate antibiotic prescribing in secondary care.

In a press release, Shallcross adds, “Probably the most robust estimates are derived national survey data in the USA, which includes emergency department and outpatient settings. These estimated that around 30% of antibiotics that are prescribed in these settings are inappropriate. More recently, a study from Australia suggested that at least one third of emergency department prescribing is inappropriate. Our estimates of inappropriate prescribing of between 60-70% are higher because we have measured how often an emergency department diagnosis of UTI is supported by clinical evidence.”

The study, “Diagnosing UTI syndromes in the emergency department a cohort study using EHR records,” will be presented in a poster presentation at ECCMID 2019 in Amsterdam, the Netherlands.