The Factors Influencing Impairment of Respiratory Function in Patients Treated for Pulmonary Tuberculosis

Abstract

PURPOSE: Tuberculosis is associated with frequent pulmonary impairment. The aim of the study was to ascertain the factors affecting lung function in patients treated for pulmonary tuberculosis. METHODS: In 302 patients who were treated for pulmonary tuberculosis (188 men and 114 women between the ages of 20 and 82 years) and observed at local dispensaries pulmonary function tests were performed. RESULTS: Pulmonary function results were normal in 149 of 302 (49,3%) patients. Pulmonary impairment was present in 153 (50,7%) patients including 101 (33,4%) patients with airway obstruction (FEV1/FVC <0.7 and TLC >80% predicted), 33 (10,9%) patients with restrictive pattern (TLC<80% predicted and FEV1/FVC ≥0.7) and 19(6,3%) patients with combined pattern (TLC<80% predicted and FEV1/FVC <0.7). Out of 302 patients, 114 (37,8%) had low lung function (FEV1 < 80% predicted). According to ATS/ERS criteria we classified 8,3% of subjects as having mild impairment; 18,2% of subjects as having moderate impairment; and 11,3% of subjects as having severe impairment. Risk factors for low lung function were positive culture in the past (odds ratio [OR] 4.3; 95% confidential interval [CI] 2.43 to 7.71; p<0.001), age 40 or older (OR 2.73; 95% CI 1.46 to 5.11; p= 0.002); recurrence of tuberculosis (OR 2.61; 95% CI 1.38 to 4.91; p=0.004); education less than 15 yrs (OR 1.79; 95% CI 1.05 to 3.05; p<0.05). We did not find influence of gender (males vs. females, OR 1.36; 95% CI 0.84 to 2.21; p>0.05) and smoking ever vs. never (OR 1.21; 95% CI 0.74 to 1.97; p>0.05) for low lung function. According to GOLD criteria we classified 13,2% of subjects as having mild COPD, 17,9% subjects as having moderate COPD, and 8,6% as having severe COPD. Risk factors for COPD were positive culture in the past (OR 1.9; 95% CI 1.14 to 3.17; p<0.05), age 40 or older (OR 3.75; 95% CI 1.95 to 7.22; p< 0.001); recurrence of tuberculosis (OR 2.35; 95% CI 1.25 to 4.42; p<0.05); gender (males vs females, OR 1.98; 95% CI 1.21 to 3.25; p<0.01); smoking ever vs. never (OR 1.88; 95% CI 1.14 to 3.11; p<0.05). CONCLUSIONS: Risk factors for pulmonary impairment were culture-positive pulmonary tuberculosis in the past, age more than 40 years, recurrence of tuberculosis, smoking, male sex which may increase the prevalence of pulmonary impairment in the patients treated for pulmonary tuberculosis.