Clinical question
Since adults aged 65 or older commonly have pyuria or bacteriuria at baseline, how should urine tests be used to identify urinary tract infections (UTIs) while avoiding potential harms of UTI overdiagnosis?
Bottom line
Urinary tract infections are widely recognized as being overdiagnosed in adults aged 65 or older, and UTIs are a primary driver of unnecessary antimicrobial use in this population that overall contributes to antimicrobial resistance.1 As we age, rates of expected colonization of the bladder increase such that as many as half of patients tested will have bacteria isolated from cultured urine, and urinalysis results will be positive most of the time.2 Asymptomatic bacteriuria (ASB) refers to this known colonization state, which does not necessarily mean the patient is asymptomatic from other acute or chronic medical conditions but that they lack specific localizing symptoms of UTI.3,4 Several randomized controlled trials have demonstrated that treating patients for ASB with antibiotics confers no benefit in terms of avoidance of UTI or improved outcome. In fact, the opposite is true. Treatment of ASB results in considerable harm, ranging from drug-related adverse effects to stepwise development of antimicrobial resistance and premature diagnostic closure that can lead to other explanations for a patient’s presentation being missed.
Case description
A 79-year-old woman with longstanding generalized anxiety presents to her primary care team following a recent fall resulting in a minor elbow laceration. Upon assessment her lorazepam is held due to concerns that this sedative is contributing to falls. Four days later she is brought in by her family due to new confusion, akathisia, and intermittent physical aggression. She is broadly investigated with a “delirium workup,” but no clear abnormalities are identified except for a urine culture that isolates Escherichia coli. She is not doing well at home and is treated with cephalexin in response to her positive urine culture results. The next day the patient develops a full body rash and her agitation worsens. She presents to the emergency department (ED) with agitation, palpitations, diaphoresis, severe hypertension, and confusion, and she is physically restrained. While waiting in the ED she experiences a witnessed generalized seizure and is admitted to critical care. Cephalexin is stopped due to concern about hypersensitivity reaction, and lorazepam is given for suspected acute benzodiazepine withdrawal. Repeat urine culture in hospital isolates mixed growth with E coli resistant to cephalexin.
Evidence
It is well established that urine cultures ordered in the absence of specific localizing symptoms of UTI in older adults frequently have positive results and represent ASB, an expected finding in this population.3,4 Unfortunately, positive culture results are often equated with the presence of UTI to explain various noninfectious presentations, leading to many avoidable patient harms ranging from drug-related adverse effects to Clostridioides difficile infection.5-8 Treatment of ASB does not improve clinically meaningful outcomes such as morbidity, mortality, or quality of life,2,9-11 nor does it reduce risk of progression to symptomatic UTI or sepsis.2,9,12 Furthermore, sustained sterilization of urine is rarely attained.2 In contrast to common perception, ASB is not a health threat and may actually be protective against risk of ascending infection.13,14 On the other hand, antibiotics aimed at ASB do the exact opposite, leading to loss of microbiome diversity and increasing the risk of UTI by as much as 300%.13 Finally, antimicrobial resistance is not only of increasing concern at the population level, it can also limit treatment options for patients who have received repeated courses of antibiotics.13
Another underemphasized risk of urine culture overuse is its impact on diagnostic accuracy due to cognitive bias introduced by positive results. Older adults often present with unique diagnostic challenges when cognitive syndromes (eg, dementia, delirium) limit the history available and have many potential causes. It is fundamentally easier to diagnose UTIs in older patients with medical complexity than it is to assess for other, more likely, explanations of their chief concerns.15,16 Common occurrences such as falls, anorexia, lethargy, and confusion may prompt reflexive urine culture testing and result in misattribution of ASB as UTI, along with delays in recognition of actual causes of these symptoms, as outlined in our case description.
Multiple systematic reviews suggest any association between UTI and delirium in older adults is likely overestimated17,18 and, in the absence of localizing urinary signs or symptoms or signs of sepsis, ASB is an unlikely cause of delirium.17,19 Current evidence suggests antimicrobial therapy for ASB does not lead to improved resolution of changes in mental status,16,20-22 improved Brief Confusion Assessment Method results, reduced risk of mortality, or reduced risk of functional decline.20,21 Rather, among hospitalized patients studied, those with ASB and no localizing urinary symptoms tended to have longer lengths of stay than their untreated counterparts23 and worse long-term functional recovery.20 Correspondingly, Infectious Diseases Society of America guidelines strongly recommend against antimicrobial treatment for older adults with delirium without local genitourinary symptoms or systemic signs of infection such as fever or hypotension.7
Approach to patients
How, then, can clinicians carefully assess older adults for possible UTI while mitigating harms of overdiagnosis and unnecessary antibiotics? Older adults are at increased risk of sepsis and poor functional outcomes; to address this, specific criteria for urine culture ordering have been established and validated in long-term care (LTC) settings.24 For patients without indwelling catheters, urine culture should be ordered for those with acute dysuria alone or with fever and at least 1 acute localizing lower urinary tract finding (eg, new or worsening urgency, frequency, suprapubic pain, gross hematuria, costovertebral angle tenderness, urinary incontinence). For patients with chronic indwelling urinary catheters, urine culture is indicated only if fever, new costovertebral tenderness, rigours, or new-onset delirium without another obvious cause is present. Because urinary catheters are colonized with bacteria and may not indicate the cause of infection, urine cultures should be collected only from the first void in the newly replaced urinary catheter.
These criteria identify the minimum clinical threshold for urine culture ordering, meaning that any patient who does not meet these criteria does not have a UTI (ie, this diagnosis can be excluded without sending a urine test),25 as described in Box 1.24,26 Since these criteria were developed for and validated in populations of LTC residents,25 who are more likely to be frail and vulnerable, the threshold for ordering urine tests in community-dwelling older adults should not be any lower.
How to approach changes in older adults’ clinical status while incorporating minimum criteria24 for UTI
Older adult is at baseline and does not meet minimum criteria for UTI:
Do not order urine culture and do not initiate antibiotics aimed at UTI
Older adult has a change from baseline but does not meet minimum criteria for UTI:
Assess for alternative explanations such as volume depletion, constipation, skin breakdown, medication side effects, and other sources of infection such as respiratory or skin and soft tissue
Do not order a urine culture but do order other targeted investigations as needed, and consider the need for encouraging increased fluid intake, monitoring, and early reassessment for development of additional signs or symptoms
Older adult has change from baseline and meets minimum criteria for UTI:
Assess resident for causes of change in status and in absence of clear alternative explanation (eg, medication change leading to delirium, other focus of infection)
Urine culture indicated in presence of minimum criteria for UTI without a clear alternative explanation
Consider the need for empiric therapy based on clinical suspicion and resident status, with a plan to reassess based on urine culture results
UTI—urinary tract infection.
Adapted from Piggott et al26 with permission from the BMJ Publishing Group Ltd. Copyright 2023.
Not ordering a urine culture does not mean withholding care. Astute clinicians will carefully explore the chronology of recent events leading to the patient’s presentation, such as consideration of inciting events (eg, recent fall or injury), change in physical environment, constipation or urinary retention, dehydration, or the start or abrupt withdrawal of any psychotropic medication.16,27
Urine cultures are one of many tests clinicians use to rule out UTIs. Urinalysis and urine dipsticks are frequently implicated in the broad-spectrum workup of older adults presenting for medical attention. While validated in younger adults, urinalysis has extremely poor performance characteristics in older populations.28 A multihospital cohort study published in 2024 demonstrated poor performance parameters of urinalysis for older adults and particularly for older women.29 Accordingly, guidelines from England and Scotland, among other countries, now recommend against use of urinalysis in the diagnosis of UTI in adults older than 65 years.30,31 Choosing Wisely Canada has similarly issued a practice change recommendation against using dipsticks or urinalysis to diagnose UTI in older adults in LTC settings.32 Long-term care homes are discouraged from purchasing, storing, or using dipsticks altogether. Similar approaches should be adopted in adults older than 65 presenting to a clinic, ED, or any other health care setting as dipsticks do not add diagnostic value and introduce potential for misdiagnosis.
Implementation
Changing clinical practice is difficult in the face of ingrained habit and established approaches to urine testing. Prescribers may benefit from reflecting on their own practices, including considerations such as whether they regularly order broad investigations such as urine testing in the absence of urinary symptoms, whether they feel undue pressure from their care team or from family members to order urine tests, or even whether urine samples are collected before they examine patients.
Specific tools that can support practice change have been developed at institutional and practice levels, including information pamphlets and visual displays, in-person and virtual seminars, group learning sessions and workshops, one-on-one coaching, and best practice advisories.33,34 Clinicians also appreciate guidance from decision support tools and initiatives when evaluating clinical indication for urine cultures.35,36 Finally, clinicians can improve patient care by physically removing urine dipsticks from their practice locations if caring only for older patients.
Patients and their loved ones are key stakeholders who can heavily influence test ordering and should be engaged in these discussions. Communication tools and strategies that support clinicians and include family members may enhance discussions on informed and shared decision making, as described in Box 2.24,26 To allay concerns that may arise related to missing potential infections, clinicians rely on other important investigations and interventions in the interim, including physical examination, clinical reassessment, medication administration review, increased monitoring for emerging clinical symptoms, and encouraging fluid intake.37,38 Furthermore, creative tools such a “prescription pad” for a nonantibiotic care plan can be potent ways to illustrate that not culturing and treating with antimicrobials does not amount to abandoning the patient or not providing care.39 Rather, a thoughtful and attentive approach to monitoring and reassessment, while mitigating risks of downstream harm, is generally appreciated by patients and their advocates.39
Examples of communication strategies for clinicians to use with families to promote judicious ordering of urine cultures for long-term care residents who lack minimum criteria24 for UTI
Identify and address family concerns:
“I am concerned about the change in clinical status that has occurred and want to assess possible causes”
“What specific symptoms have been voiced, and what have you noticed?”
Discuss findings:
“Based on my assessment, there is no evidence of bladder infection and antibiotics would cause unnecessary harm”
“If we collect a urine culture in this situation, we may only identify bacteria that are protective and not indicate presence of infection”
“National and international guidelines recommend against a urine culture in this situation, as the diagnosis of UTI is unlikely based on clinical criteria alone”
Implement a safety plan:
“We should encourage oral intake, and I have requested more frequent monitoring over the next 24 hours”
“Should there be any new or worsening symptoms, a fresh assessment should be performed”
UTI—urinary tract infection.
Adapted from Piggott et al26 with permission from the BMJ Publishing Group Ltd. Copyright 2023.
Case resolution
Following her critical care unit stay, the patient is transferred to the medicine ward where she arrives physically deconditioned, far from her physical baseline at the time of admission. She requires a prolonged stay in hospital while her delirium resolves. She is subsequently transferred to a slow-stream rehabilitation program to regain her baseline function before being discharged home.
Conclusion
Our patient presented with confusion and agitation related to acute benzodiazepine withdrawal, but reflexive delirium investigations were sent (including urine culture), resulting in premature diagnostic closure, missed opportunity for appropriate treatment, unnecessary antimicrobial exposure, and subsequent preventable adverse events including functional decline, seizure, and critical care admission. We are reminded to treat the patient, not the laboratory test result, and that unnecessary urine cultures are an established driver of inappropriate antimicrobial prescribing. Minimum clinical criteria exist to guide clinicians in following evidence-based definitions of UTI and not ordering urine cultures for presentations that fall below this threshold. Altered sensorium can present diagnostic challenges, but guidelines advocate against routinely culturing and treating UTI in the absence of acute localizing urinary findings. In the absence of signs of sepsis, treatment of bacteriuria in patients with delirium does not improve outcomes. In this situation, clinicians are more likely to be successful by taking a careful history and performing a physical examination than by reflexively ordering urine testing. Effective communication with patients and their families will engender support to tailor investigations based on clinical suspicion rather than reflexive use of tests with poor performance characteristics that contribute to avoidable patient harms.
Acknowledgment
No specific patient information, explicit or anonymized, has been included in this article. The case example is based on the combined clinical experience of the contributing authors and contains no specific patient information.
Notes
Choosing Wisely Canada is a campaign designed to help clinicians and patients engage in conversations about unnecessary tests, treatments, and procedures and to help physicians and patients make smart and effective choices to ensure high-quality care is provided. To date there have been 13 family medicine recommendations, but many of the recommendations from other specialties are relevant to family medicine. Articles produced by Choosing Wisely Canada in Canadian Family Physician are on topics related to family practice where tools and strategies have been used to implement one of the recommendations and to engage in shared decision making with patients. If you are a primary care provider or trainee who has used Choosing Wisely recommendations or tools in your practice and you would like to share your experience, please contact us at info{at}choosingwiselycanada.org.
Footnotes
Competing interests
None declared
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La traduction en français de cet article se trouve à https://www.cfp.ca dans la table des matières du numéro de septembre 2024 à la page e129.
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