Chest computed tomography scan utilization and diagnostic outcomes in chronic cough patients with normal chest X-rays: analysis of routinely collected data of a tertiary academic hospital

Background: The role of chest computed tomography (CT) scan is controversial in the management of chronic cough patients with normal chest X-rays. We investigated the utilization pattern and diagnostic outcomes of chest CT scans using institutional routinely collected data (RCD) in South Korea. Methods: This is a retrospective analysis of adults with chronic cough (>8 weeks in duration) identified from routinely collected electronic health records (EHRs). Structured data were retrieved, including demographics, medical history, symptoms, and diagnostic test results (including chest X-rays and CT scans). Chest CT scan outcomes were classified into major abnormal findings (malignancy, infectious diseases, or other critical conditions that warrant immediate treatment decisions), minor abnormal findings (other abnormal findings), or normal CT. Results: A total of 5,038 chronic cough patients with normal chest X-rays were analyzed. Chest CT scans were performed in 1,006 patients. Prescription of CT scans was significantly associated with older age, male sex, smoking history, and physician-diagnosed history of lung disease. Only 8 of 1,006 (0.8%) patients had major abnormal findings (4 pneumonia, 2 pulmonary tuberculosis, and 2 lung cancer), while 367 (36.5%) had minor findings, and 631 (62.7%) had normal CT scans. However, no baseline parameters were significantly associated with major CT findings. Conclusions: Chest CT scans were frequently prescribed for chronic cough patients with normal chest X-rays, and abnormal findings were frequently found (37.3%). However, the diagnostic yield for malignancy or infectious disease were low (<1%). Given the potential radiation harm, a routine chest CT scan may not be warranted in chronic cough patients with normal chest X-rays.