Respiratory Symptoms and Predictors of Abnormal Lung Function in Post-tuberculosis Lung Disease Patients – A Cross Sectional Comparative Study

Background Patients treated for pulmonary tuberculosis and cured still come down with persistent respiratory symptoms and impaired lung function, this study assessed respiratory symptoms and predictors of abnormal lung function in post-tuberculosis lung disease patients. Methods This was a hospital based cross sectional comparative study of post pulmonary tuberculosis patients attending Federal Teaching Hospital, Owerri, who completed treatment at the point of treatment completion down/up to 2 years previously. Interviewer based questionnaire was administered to study participant to obtain data regarding socio demographics. All participants were subjected to spirometry procedure to measure the ventilatory function parameters using spirolab III. Data was analyzed using IBM SPSS statistics version 25.0. Chi-square was used to determine association between categorical variables. The independent student t-test was used to compare continuous data. Logistics regression model was used to assess predictors of spirometric impairment in post-TB lung disease cases. A p-value less than 0.05 was considered statistically significant. Results Out of the 200 participants recruited, consisting of 100 post-tuberculosis lung disease patients (18 years and above) and 100 age-, sex- and height-matched apparently healthy controls. mean age: 48.0 ± 15.2 for cases and 46.7 ± 13.9 for controls, range 18–90 years with most of the participants between 45–54 years. The most frequent respiratory symptom was cough which was present in 56 (56%) of the cases followed by sputum production in 51 (51%), breathlessness 34 (34%), chest pain 31 (31%), wheezing 13 (13%) and haemoptysis 10 (10%) while none of the controls had respiratory symptoms. Respiratory lung function impairment occurred in 71% of cases and 12% of the control. The odds of lung function impairment were 18.0 (95% CI: 8.55 to 37.7, p < 0.001) times higher in post-tuberculosis patients than controls. Only lower body mass index (aOR 0.20, 95% CI: 0.07 to 0.52) was found to independently predict impaired lung function in post-TB cases after adjusting for confounders while no significant association was found with age group, sex, educational status, previous TB treatment and presence of respiratory symptoms. Conclusion There was significant burden of respiratory symptoms among treated and cured post-tuberculosis lung disease patients. Most of the patients had persistent respiratory symptoms post-tuberculosis treatment and cure, cough was the most common symptom followed by sputum production. There was poor correlation between respiratory symptoms and abnormal lung function, only body mass index showed significant association with abnormal lung function.