SESSION TITLE: Respiratory Infections Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PM
PURPOSE: Pulmonary tuberculosis can be a cause of restrictive impairment. Little is known about the prevalence of restriction in patients after pulmonary tuberculosis. The presence of true restriction requires the measure of total lung capacity (TLC). The objectives of the study were (1) to evaluate the prevalence of true restriction in patients who had been treated for pulmonary tuberculosis, (2) to ascertain the factors influencing restrictive impairment, (3) to predict low TLC based on spirometry.
METHODS: In 306 patients (between the ages of 20 and 82 years, 190 males and 116 females) spirometry and bodyplethysmography were performed at least two years after the treatment.
RESULTS: Overall, we found that 16% (49/306) had restrictive impairment (TLC less 80% predicted) and 17,6% (54/306) patients had forced vital capacity (FVC) less 80% predicted (p>0.05). Risk factors for restrictive impairment were positive culture in the past (odds ratio [OR] 3.98; 95% confidential interval [CI] 1.7 to 9.3; p<0.001), relapse of pulmonary tuberculosis (OR 2.22; 95% CI 1.07 to 4.58; p<0.05). We did not find influence of age, education, gender and smoking for restrictive impairment. Using Receiver Operating Characteristics (ROC) curve analysis we evaluated FVC% predicted, forced expiratory volume in 1 second (FEV1% predicted), FEV1/FVC, peak expiratory flow (PEF% predicted), maximum mid-expiratory flow (MMEF% predicted), forced expiratory flow (FEF) when 25% of the FVC has been expired (FEF25% predicted), FEF50% predicted, FEF75% predicted, FEV1% predicted-FVC% predicted, (FEV1/FVC% predicted)/FVC% predicted for predicting low TLC. Among all variables, the area under the ROC curve (AUC) was the highest for FVC% (0,953; 95% CI 0.923 to 0.974). When 85% of FVC was chosen as the cut-off, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 93.9%, 90.3%, 64.8%, and 98.7%, respectively. The sensitivity, specificity, PPV and NPV of the other algorithm [Glady C, Chest 2003] were found 75.5%, 94.6%, 72.5%, and 95.3%, respectively.
CONCLUSIONS: The prevalence of true restriction was 16% in patients with treated pulmonary tuberculosis. Risk factors for restrictive impairment were culture-positive pulmonary tuberculosis in the past, relapse of tuberculosis.
CLINICAL IMPLICATIONS: FVC less 85% predicted suggests a high probability of restrictive impairment.
DISCLOSURE: The following authors have nothing to disclose: Mikhail Chushkin, Sergey Mandrykin, Eduard Tikhokhod, Sergey Smerdin
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