Association Between Physical Function, Pulmonary Function, and Social Determinants of Health in Individuals with Post-Tuberculosis Lung Disease

Although poverty and tuberculosis are insidiously linked, knowledge of the relationship between social determinants of health (SDoHs) and post-tuberculosis lung disease (PTLD) is limited. This study aimed to analyze the association between physical function, pulmonary function, and SDoHs in individuals with PTLD (iwPTLD), considering the impact of social inequalities on physical performance. This cross-sectional study collected social data from 69 iwPTLDs using a standardized assessment form. The patients underwent pulmonary function testing via spirometry and body plethysmography, as well as respiratory muscle strength and quadriceps muscle strength (QMS) testing. They also completed the six-minute step test (6MST). The median value of steps climbed by participants on the 6MST was 88 (57–117), corresponding to 50.1% (34.9–73.2) of the predicted value. The mean QMS was 28.7 ± 11.9 kgf, with 11 participants (17.4%) showing QMS below the cutoff point. Spirometry revealed normal, obstructive, restrictive, and mixed patterns in 19 (27.5%), 20 (29%), 18 (26.1%), and 12 (17.4%) of the participants, respectively. Performance on the 6MST showed no statistically significant association with SDoHs. QMS showed a statistically significant association with treated sewage (W = 84, p = 0.026). Forced expiratory volume in one second showed significant correlations with education level (ρ = 0.248, p = 0.040), social protection (W = 207, p = 0.050, r = 0.238), and treated water (W = 24.5, p = 0.029, r = 0.264). Maximum inspiratory pressure showed significant correlations with education level (ρ = 0.246, p = 0.042) and treated water (W = 20, p = 0.021, r = 0.280). The regression model for 6MST and QMS performance showed that 12% and 45% of the variability was explained by the studied variables, respectively. In iwPTLD, impairments in physical function and damage to lung function are weakly associated with the deterioration of SDoHs. While this relationship is weak, it should not be ignored because it may operate through indirect pathways.