Impact of Type 2 Diabetes on Manifestations and Radiological Images of Pulmonary Tuberculosis

Objective To explore the clinical features of pulmonary tuberculosis complicated with DM and related factors. Method The manifestations of 87 newly diagnosed PTB patients with type 2 DM(DM-PTB group) at two hospitals in Tianjin during October 2003 to October 2004 were compared to 88 PTB patients without DM who were randomly choosen from the same hosipital.The factors related to sputum-positive TB or cavity were explored through unconditional logistic regression model. Results DM-PTB patients showed significanly lower frequencies of cough(66.7% vs 83.0%),toxicity symptoms(37.9% vs 62.5%) and haemoptysis(16.1% vs 33.0%) than those of PTB group.Positive-sputum(63.2% vs 34.1%),cavity(56.3% vs 13.6%),wide lesions and bilateral lesions on chest radiographs was more common in DM-PTB group than in PTB one.Introversion(OR=1.582, 95%CI:1.063 ～2.355),type 2 DM(OR =2.186,95% CI:1.082 ~4.420)and cavity(OR =2.793,95% CI:1.308 ～5.964)were factors independently associated with positive-sputum TB.The factors related to cavity included diabetes(OR=14.199,95%CI:5.376~ 37.501),cough,postive sputum and lore-up lobe lesion.Conclusion This study confirmed that clinical manifestations and chest radiographs of PTB patients complicated with type 2 DM significantly departed from the typical presentation.Type 2 DM seems to have a negative effect on postive-sputum and cavity.So it should be alarmed that DM-PTB patients who tend to have untypical clinical symptom and higher rate of positive sputum become the reservoirs of infection to cause the transmission of TB.