Evaluation of functional capacity, lung function, muscle strength and quality of life in patients with post-tuberculosis lung disease

Abstract

Introduction: Tuberculosis (TB) is an infectious disease that causes a major impact on Public Health. Post-TB lung disease (PD-PTB) causes structural and functional sequelae such as pleural thickening, bronchiectasis and pulmonary fibrosis, generating an obstructive, restrictive or mixed pattern and directly impacting health-related quality of life (HRQoL). The prevalence of pulmonary sequelae of TB varies widely, from 18% to 87%, depending on the population studied and the pulmonary function tests performed. Prospective data on the long-term outcomes of PD-PTB remain limited and there are still no validated prognostic scores. The assessment of PD-PTB must be carried out clinically with every patient who completes TB treatment. The assessment of functional capacity, muscle strength, lung function and HRQoL in individuals with PD-PTB is of great relevance for clinical practice, enabling the establishment of appropriate therapeutic plans. Objective: The objective of this Dissertation was to evaluate functional capacity in patients with PD-PTB and correlate these findings with lung function, peripheral muscle strength and HRQoL. Methods: This is a cross-sectional and observational study, with quantitative evaluation of sample data. The present study was carried out in the Pulmonary Function Laboratory of the Pedro Ernesto University Hospital, of the State University of Rio de Janeiro (HUPE-UERJ). 47 patients of both sexes who had TB and remain with respiratory symptoms were evaluated. After measuring anthropometric and demographic variables, patients were evaluated using the following tests: pulmonary function (spirometry, body plethysmography and measurement of carbon monoxide diffusion capacity-DLCO; measurements of maximum inspiratory pressure-MIP and maximum expiratory pressure-MEP; peripheral muscle strength (handgrip and quadriceps strength); and assessment of functional capacity through the ADL-Glittre test. Results: The mean age was 57 (32–65) years, while the median time since the end of TB treatment was 30 (26–33) months. Handgrip and quadriceps strengths were reduced in 34% and 25.5% of participants, respectively. On spirometry, obstructive pattern, restrictive pattern, and normal examination were diagnosed in 46.8%, 31.9%, and 21.3% of participants, respectively, while 42.6% of participants had reduced DLCO. The median TGlittre time value was 4.43 (3.48–4.96) min, which was approximately 15% longer than the expected time to complete it. There was a significant correlation between TGlittre time and DLCO (rs=-0.532, P<0.0002), MIP (rs=-0.407, P=0.005), MEP (rs=-0.382, P=0.008), handgrip (rs=-0.327, P=0.024), quadriceps strength (rs=-0.314, P=0.031) and several domains of the SF-36. In the regression analysis, DLCO, quadriceps strength and handgrip explained 39% of the variability in TGlittre time. Conclusion: PD-PTB causes important repercussions on functional exercise capacity assessed by TGlittre. These patients present muscle dysfunction, deteriorated HRQoL and damage to lung function. In PD-PTB, the worse the muscle and lung function, the worse the functional exercise capacity.