Spirometry results after treatment for pulmonary tuberculosis: comparison between patients with and without previous lung disease: a multicenter study

OBJECTIVE: To compare patients with and without previous lung disease, in terms of the spirometry results after they had been treated for pulmonary tuberculosis (PTB) and cured, as well as to analyze risk factors related to functional severity. METHODS: This was a cross-sectional, multicenter study conducted at four referral centers in Brazil. Patients were divided into two groups: those with a history of lung disease or smoking (LDS+ group); and those with no such history (LDS− group). Patients underwent spirometry (at least six months after being cured). Sociodemographic and clinical data were collected. RESULTS: A total of 378 patients were included: 174 (46.1%) in the LDS+ group and 204 (53.9%) in the LDS− group. In the sample as a whole, 238 patients (62.7%) had spirometric changes. In the LDS+ group, there was a predominance of obstructive lung disease (in 33.3%), whereas restrictive lung disease predominated in the LDS− group (in 24.7%). Radiological changes were less common in the LDS− group than in the LDS+ group (p < 0.01), as were functional changes (p < 0.05). However, of the 140 (79.1%) LDS− group patients with a normal or minimally altered chest X-ray, 76 (54%) had functional changes (p < 0.01). The risk factors associated with functional severity in the LDS− group were degree of dyspnea (p = 0.03) and moderate or severe radiological changes (p = 0.01). CONCLUSIONS: Impaired pulmonary function is common after treatment for PTB, regardless of the history of lung disease or smoking. Spirometry should be suggested for patients who develop moderate/severe dyspnea or relevant radiological changes after treatment for PTB.