Department of Infectious Diseases Saint Vincent Hospital, United States
Introduction: The obesity pandemic presents numerous challenges in radiography, including patients exceeding the weight limits of imaging equipment and motion artifacts due to increased exposure. Pneumonia is a common reason for hospital admission, but identifying an infiltrate on the chest radiograph (CXR) in obese patients can be challenging. Conversely, motion artifacts may be misinterpreted pneumonia. This study aimed to assess the diagnostic utility of CXR for identifying pneumonia in obese patients by comparing it with CT scans performed within 72 hours, and also to determine its impact on antibiotic initiation or discontinuation.
Methods: The study included all patients admitted between July 2020 and 2022 with a diagnosis of pneumonia who underwent both CXR and CT Chest within a 72-hour window. Patients were divided into two groups based on their BMI: obese and non-obese. The imaging results were evaluated to determine the agreement in diagnosing pneumonia, as well as its influence on antibiotic therapy.
Results: 320 patients were included in the study, with a mean age of 65.3 years. 146 (45.6%) were male, and 174 (54.4%) were female. Among the participants, 202 (63.1%) were classified as obese (BMI > 30). CXR was first performed in 313 (97.8%) cases, while 7 (2.2%) underwent CT scan first. In the obese group, 196 (97.0%) underwent CXR first, followed by CT scan. The overall agreement for diagnosing pneumonia was 67.5% (p=0.001). In the non-obese group 117 (99.2%) patients underwent CXR first, with an overall agreement of 80.2% (p < 0.001). Among the obese patients who underwent CXR first, 11 (5%) had antibiotics discontinued after the CT scan results, while the number was 4 (3%) in the non-obese group. Additionally, 3 patients in the obese group had antibiotics initiated after the CT scan.
Conclusions: Obesity poses unique challenges to facilities and imaging equipment, leading to technical difficulties. Diagnosing pneumonia in obese patients using CXR may be challenging and can result in overdiagnosis of potential infiltrates or opacities. This may lead to unnecessary prolonged antibiotic use or, in some cases, missing the diagnosis and undertreatment. A CT scan is more sensitive and is necessary to identify underlying pneumonia accurately in these patients and facilitate appropriate antibiotic use.
