Abstract:

Objective To analyze the performance of superoxide dismutase (SOD) and the common clinical biomarkers for diagnosis of secondary pulmonary tuberculosis complicated with respiratory failure.Methods The peripheral blood of 143 cases with secondary pulmonary tuberculosis in Beijing Chest Hospital, Capital Medical University between March 2015 and December 2015 were collected in this study. Among the included patients, there were 71 cases with pulmonary tuberculosis (defined as pulmonary tuberculosis group) and 72 cases with secondary pulmonary tuberculosis complicated with respiratory failure (defined as respiratory failure group). The levels of concentrations of SOD, hypersensitive C reactive protein (HCRP), erythrocyte sedimentation rate (ESR) and NT-proBNP were tested.Results The level of SOD was 524.16±225.97mg/ml in respiratory failure group, which was lower than that in the pulmonary tuberculosis group (725.34±325.63mg/ml). The level of HCRP was 68.51±43.6mg/L in respiratory failure group, which was higher compared with the pulmonary tuberculosis group (56.07±39.56mg/L). The ESR was 50.05±29.03mm/1h in respiratory failure group, higher than that in pulmonary tuberculosis group (37.13±27.58mm/1h). The level of NT-proBNP was 882.19±182.36ng/L in respiratory failure group, which was higher than that in the in pulmonary tuberculosis group (360.26±73.99ng/L). The differences in the levels of SOD, HCRP, ESR and NT-proBNP were statistically significant (t=3.90, 1.78, 2.69 and 22.78; Ps<0.05). The logistic multivariate analysis showed that the risk of respiratory failure in pulmonary tuberculosis patients with a SOD level of ≥300mg/ml was 89% compared with patients with a SOD level of <300mg/ml (OR=0.89; 95%CI=0.76-0.92); the risk in patients with a NT-proBNP level of ≥80ng/L was 1.21 times of patients with a NT-proBNP of <80ng/L (OR=1.21; 95%CI=1.12-1.28). Receiver operating characteristic curves (ROC) analysis showed that area under curve (AUC) of SOD in diagnosing respiratory failure in pulmonary tuberculosis patients was 0.862, followed by NT-proBNP, HCRP and ESR. the sensitivity of SOD was 73.2% and specificity was 93.1%; the cut-off value was 478.51mg/ml. AUC of NT-proBNP was 0.764, the sensitivity of NT-proBNP was 72.5% and specificity was 82.7%, and the cut-off value was 340.20pg/ml.Conclusion The plasma levels of SOD and NT-proBNP have good clinical values in monitoring the occurrence of respiratory failure in secondary pulmonary tuberculosis patients.

Key words: Tuberculosis, pulmonary, Respiratory insufficiency, Superoxide dismutase, Diagnosis, Evaluation studies