Risk factors of delayed isolation of patients with pulmonary tuberculosis

The aim was to examine the rate of delayed or no isolation of hospitalized patients with pulmonary tuberculosis (TB) and the causes for isolation failure.

This retrospective study included patients with pulmonary TB at a university-affiliated hospital in South Korea between January 2015 and June 2018 after excluding those with a stay ≤2 days and those who only visited the emergency department. Patients who were not isolated for ≥3 days were classified as the delayed or no isolation group. We compared the clinical findings and diagnostic test results, between patients managed with delayed or no isolation (D-isolation) and timely isolation (T-isolation).

Of 486 patients with pulmonary TB, 222 patients were included. In 106 cases (47.7%), isolation was delayed or not applied, while in 116 cases, isolation was applied in a timely manner. Typical findings of TB were seen on the chest X-rays of 87 (75.0%) patients in the T-isolation group versus 25 (23.6%) patients in the D-isolation group (p < 0.001). Other factors significantly associated with delayed or no isolation on univariate analyses were older age, admission route (emergency room vs. other), admitting department, negative acid-fast bacilli (AFB) stain, and negative MTB PCR. On multivariate analysis, admission through an outpatient clinic, admission to a department other than infectious diseases or pulmonology, an atypical chest X-ray finding and negative sputum AFB stains were risk factors for isolation failure.

Delayed or no isolation of patients with pulmonary TB was attributed mainly to atypical radiological findings and negative findings of direct TB diagnostic tests.