Proposing the “Continuum of UTI” for a Nuanced Approach to Diagnosis and Management of Urinary Tract Infections

Abstract

Purpose:

Patients with suspected UTIs are categorized into 3 clinical phenotypes based on current guidelines: no UTI, asymptomatic bacteriuria (ASB), or UTI. However, all patients may not fit neatly into these groups. Our objective was to characterize clinical presentations of patients who receive urine tests using the “continuum of UTI” approach.

Materials and Methods:

This was a retrospective cohort study of a random sample of adult noncatheterized inpatient and emergency department encounters with paired urinalysis and urine cultures from 5 hospitals in 3 states between January 01, 2017, and December 31, 2019. Trained abstractors collected clinical (eg, symptom) and demographic data. A focus group discussion with multidisciplinary experts was conducted to define the continuum of UTI, a 5-level classification scheme that includes 2 new categories: lower urinary tract symptoms/other urologic symptoms and bacteriuria of unclear significance. The newly defined continuum of UTI categories were compared to the current UTI classification scheme.

Results:

Of 220,531 encounters, 3392 randomly selected encounters were reviewed. Based on the current classification scheme, 32.1% (n = 704) had ASB and 53% (n = 1614) did not have a UTI. When applying the continuum of UTI categories, 68% of patients (n = 478) with ASB were reclassified as bacteriuria of unclear significance and 29% of patients (n = 467) with “no UTI” were reclassified to lower urinary tract symptoms/other urologic symptoms.

Conclusions:

Our data suggest the need to reframe our conceptual model of UTI vs ASB to reflect the full spectrum of clinical presentations, acknowledge the diagnostic uncertainty faced by frontline clinicians, and promote a nuanced approach to diagnosis and management of UTIs.

Practice guidelines recommend against antibiotic treatment for asymptomatic bacteriuria (ASB), which occurs in up to 50% of hospitalized patients.1 Despite this strong recommendation, a large proportion of patients with ASB are treated with antimicrobials for a UTI.2,3 Treatment of ASB is associated with increased length of stay, antibiotic resistance, and Clostridioides difficile infection (CDI).3 However, 2 major challenges exist with appropriate management of patients with suspicion of UTI.

First, patients with positive urine cultures have historically been diagnosed with ASB or UTI based on absence or presence of symptoms referrable to the urinary tract.1 The Infectious Diseases Society of America (IDSA) guidelines recommend against antimicrobials in older adults with cognitive impairment and delirium in the absence of localized genitourinary symptoms or other systemic signs of infection.1 However, many hospitalized patients, especially older adults, often present to the emergency department (ED) with nonspecific symptoms like fever, hypotension, and delirium in the setting of abnormal urine tests.4-6 Because of the diagnostic uncertainty in these cases, frontline clinicians perceive these patients to be symptomatic and often treat with antimicrobials for UTI.7 Antibiotic stewardship teams, on the other hand, classify these patients as ASB and recommend withholding antibiotics. These clinical scenarios highlight differences between the frontline clinicians’ and antibiotic stewardship teams’ definitions of “asymptomatic,” highlighting the ambiguity of the term “ASB.”8

Second, urine culture thresholds of 100,000 CFU/mL have been recommended for diagnosis of cystitis and ASB by regulatory agencies and IDSA.1,9,10 This cutoff of 100,000 CFU/mL is based on 1 study performed over 60 years ago.11 Since then, several studies have identified subsets of women who present with pyuria and symptoms consistent with a UTI, but who have colony counts < 100,000 CFU/mL in voided urine.12,13 Furthermore, lower colony counts may be treated as contamination or colonization and may not even be reported by laboratories, despite potential clinical significance.14

Our objectives were (1) to understand the clinical presentation of patients who receive urine tests in a cohort of diverse hospitals and (2) to characterize the “continuum of UTI” and compare with the current classification scheme.

Advani SD, Turner NA, North R, Moehring RW, Vaughn VM, Scales CD, et al. Proposing the “Continuum of UTI” for a Nuanced Approach to Diagnosis and Management of Urinary Tract Infections. Journal of Urology [Internet]. 2024 May 1 [cited 2025 May 8];211(5):690–8. Available from: https://doi.org/10.1097/JU.0000000000003874