The impact of glycemic status on radiological manifestations of pulmonary tuberculosis in diabetic patients

SETTING: Diabetes mellitus (DM) may increase risk of pulmonary tuberculosis (PTB) and influence its radiological manifestations. OBJECTIVE: To evaluate the impact of glycemic status on radiological findings of PTB in diabetic patients. METHODS: Between January 2010 and December 2015, chest radiographs (CXRs) in consecutive 214 DM patients with culture-proved PTB and 123 available thoracic computed tomography (CT) scans were enrolled. An equal number of non-DM patients with similar demographics was included as the control group. Glycemic status was assessed by glycosylated hemoglobin (HbA1c), and a cutoff of 8% was used to further investigate radiological features of diabetic PTB. Two radiologists and one pulmonologist reviewed the chest images independently. RESULTS: Compared with non-DM patients, primary PTB pattern and extensive disease on CXRs as well as primary PTB pattern, large non-cavitary nodule, more than one cavity in a single lesion, unusual location, and all lobe involvement of lesions on thoracic CT scans were more common in DM patients. Furthermore, diabetics with HbA1c > 8% were more likely to exhibit unusual findings (P < 0.001), far advanced extensive lesions (P < 0.001) on CXRs, lymphadenopathy (P = 0.028), more than one cavity in a single lesion (P < 0.001) and all lobe involvement (P = 0.041) on thoracic CT scans. CONCLUSIONS: Glycemic status influenced radiological manifestations of diabetic PTB. Given an increased risk of atypical radiological presentations of PTB in DM patients, physicians should be alert and pay more attention to those with poor glycemic control.