Most accident and emergency patients with a suspected urinary tract infection (UTI) and who are treated with antibiotics actually lack evidence of this infection, warn UK researchers.
They found that only one third of patients that enter the A&E department with suspected UTI actually have evidence of one, yet almost all are treated with antibiotics.
“A focus on antibiotic review in patients with an A&E diagnosis of suspected UTIs could support reductions in inappropriate prescribing”
This trend is unnecessarily driving the emergence of antimicrobial resistance, warned the authors of the study, led by Dr Laura Shallcross, from University College London.
They noted that concern over delaying antibiotic treatment for severe infection means that clinicians have a low threshold for initiating antibiotics in A&E for patients with suspected UTI syndromes.
Although a non-infectious cause was established for many of these cases, antibiotics were often continued unnecessarily, which drives the emergence of antimicrobial resistance, they warned.
In their study, the authors estimated the frequency of over-diagnosis of UTI syndromes in A&E, in order to estimate the potential to reduce antibiotic prescribing by stopping antibiotics early for patients with no evidence of bacterial infection.
They carried out their study in a large teaching hospital, the Queen Elizabeth Hospital in Birmingham, using electronic health records from patients with suspected UTI syndromes who attended A&E.
Source: Tony Hisgett
Individuals who had a sample submitted for microbiological culture of urine in the emergency department were eligible for inclusion.
The researchers randomly selected a subset of 1000 patients (700 admitted to hospital) and described the clinical and demographic characteristics of this population.
They then compared diagnoses made by the ED physician to clinical diagnosis based on urinary symptoms and microbiological outcomes and international classification of disease (ICD-10) diagnostic codes.
Finally, they estimated how often antibiotics were stopped at or shortly after (<72 hours) admission to hospital.
A total of 943 patients were eligible for the study. Of these, 289 patients had an A&E diagnosis of UTI syndromes including 56 cases of pyelonephritis, 42 cases of urosepsis and 191 cases of lower UTI.
Treatment with empirical antibiotics was recorded for 173 (91%) of patients with an emergency department diagnosis of lower UTI, but only 63 of these cases (36.4%) had clinical evidence of UTI.
The researchers found that ICD-10 diagnostic codes were available for 83 patients with lower UTI who had been admitted to hospital.
Of these, more than 40% (34/83) had a primary diagnostic code for a non-infectious condition, suggesting antibiotic treatment was not required.
The authors said: “A focus on antibiotic review in patients with an emergency department diagnosis of suspected UTIs could support reductions in inappropriate antibiotic prescribing in secondary care, and help reduce the impact of unnecessary prescribing on the development of antibiotic resistance.”
They added that it was difficult to generate accurate estimates of overprescribing.
“We have measured how often an emergency department diagnosis of UTI is supported by clinical evidence”
Dr Shallcross said: “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,” she said.
“More recently, a study from Australia suggested that at least one third of emergency department prescribing is inappropriate,” she noted.
She said: “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 authors highlighted that antimicrobial stewardship initiatives, such as the Department of Health and Social Care’s Start Smart then Focus, recommend all antibiotic prescriptions should be reviewed, taking account of clinical progression and microbiological results.
Dr Shallcross added: “Our study highlights the potential impact on total antibiotic prescribing – and antibiotic resistance – that could be achieved by widespread adoption of such initiatives.”
The findings were presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Amsterdam in the Netherlands, which is on during 13-16 April.
- See attached PDFs below for study abstract and poster