Accuracy of Current Diagnostic Criteria for Acute Bacterial Infection in Older Adults in the Emergency Department

Abstract

Objectives To evaluate the accuracy of emergency department (ED) physicians’, the Loeb criteria, and CDC guideline diagnoses of acute bacterial infection in older adults compared to a gold standard expert review. Design Prospective, observational study. Setting Urban, tertiary-care ED. Participants ED patients aged ≥65 years, excluding those incarcerated, traumas, non-English speaking, or unable to consent. Measurements Two physician experts identified bacterial infections using clinical judgement, patient surveys, and medical records; a third adjudicated in cases of disagreement. Agreement and test characteristics were measured for ED physician diagnosis, Loeb criteria, and CDC surveillance guidelines. Results Gold-standard review identified bacterial infection in 77/424 patients (18%): 18(4.2%) lower respiratory, 19(4.5%) urinary tract (UTI), 22(5.2%) gastrointestinal, and 15(3.5%) skin/soft tissue. ED physicians diagnosed infection in 71 (17%), but there were 33 with under- and 27 with over-diagnosis. Physician agreement with the gold standard was moderate for infection overall and each infection type (kappa [k] 0.48–0.59), but sensitivity was low (<67%), and negative likelihood ratio (LR[−]) >0.30 for all infections. Loeb criteria had poor sensitivity, agreement, and LR(−) for lower respiratory (50%; k=0.55; 0.51) and UTI (26%; k=0.34; 0.74), but 87% sensitivity (k=0.78; LR[−] 0.14) for skin/soft tissue infection. CDC guidelines had moderate agreement, but poor sensitivity and LR(−). Conclusions Infections are often under- and over-diagnosed by emergency physicians in older adults. The Loeb criteria are useful only for diagnosing skin/soft tissue infections. CDC guidelines are inadequate in the ED. New criteria are needed to aid ED physicians in accurately diagnosing infection in older adults.

Nonspecific Symptoms Lack Diagnostic Accuracy for Infection in Older Patients in the Emergency Department

“…The primary study included 424 subjects . Table provides patient characteristics overall and stratified by presence of infection.…”

“…1 Accurate infection diagnosis is complicated by the absence of typical symptoms found in younger adults, lack of accurate diagnostic criteria, absence of timely culture results, long-term microorganism colonization, and comorbidities. [2][3][4][5] Both overdiagnosis and underdiagnosis can occur. 2,6 Overdiagnosis may result in increased costs, inappropriate antibiotic use, missed alternative diagnoses, and preventable admissions.…”

“…[2][3][4][5] Both overdiagnosis and underdiagnosis can occur. 2,6 Overdiagnosis may result in increased costs, inappropriate antibiotic use, missed alternative diagnoses, and preventable admissions. 5,[7][8][9] Underdiagnosis can result in failure to adequately treat bacterial infections.…”

Diagnosis of urinary tract infection in older persons in the emergency department: To pee or not to pee, that is the question

“…Both under‐diagnosis and over‐diagnosis is common, but over‐diagnosis seems the more pressing problem in geriatric emergency medicine and is the focus of this article. A retrospective study of emergency admissions of those aged 75+ years treated with intravenous antibiotics for a UTI found that 43% did not meet defined criteria for that diagnosis.…”

Reply to: Some Concerns About Diagnostic Test Accuracy for Infections

“…al.’s interest in our article and thank them for their comments. 1,2 They are correct in noting that the 24/7/365 nature of emergency medicine can pose challenges to interpretation of clinical research. The ideal population they describe is not obtainable in the vast majority of emergency departments (EDs) due to staffing challenges and expense associated with around the clock research coordinator coverage.…”