Exploratory Associations Between Deep Core Muscle Function and Pulmonary Function Across GOLD Stages in Individuals With COPD.

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is associated with diaphragm dysfunction and reduced functional capacity. Altered deep core muscle function, particularly of deep abdominal muscles may further compromise postural stability and functional performance. However, objective clinical assessment of deep core muscle activation across COPD severity remains underexplored.

PURPOSE: To explore potential associations between deep core muscle function using a pressure biofeedback unit (PBU) and Pulmonary Function parameters (PFT) across Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages in individuals with COPD.

METHODS

In this cross-sectional exploratory study, 84 individuals with COPD were assessed. Pulmonary function (FEV1, FVC and FEV1/FVC) was measured using spirometry. Deep core muscle function was evaluated using a Pressure Biofeedback Unit (PBU) during the Abdominal Drawing-In Maneuver (ADIM) in prone position. Associations between PBU measures and pulmonary function parameters were examined using Spearman's correlation including exploratory analysis across GOLD stages.

RESULTS

Deep core muscle function demonstrated statistically significant negative correlations with pulmonary function parameters, including FEV1/FVC (ρ = -0.55; p < 0.001), FEV1 (ρ = -0.72; p < 0.001) and FVC (ρ = -0.59; p < 0.001). Mean PBU pressure values progressively increased across GOLD stages (Kruskal-Wallis H (3) = 50.053; p < 0.001; Ɛ2 = 0.59). Stage-wise exploratory analyses demonstrated variable correlations across GOLD stages, however findings should be interpreted cautiously due to small subgroup sample sizes.

DISCUSSION: Deep core muscle function assessed via pressure biofeedback demonstrated exploratory association with pulmonary function and varied across COPD severity categories. Participants with greater airflow limitation generally exhibited poorer deep abdominal muscle activation. These findings indicate a possible association between COPD severity and altered deep core muscle activation patterns. However, due to the exploratory cross-sectional design and methodological limitations, the findings should be considered hypothesis-generating rather than confirmatory. Longitudinal and interventional studies are required to further investigate these associations.

TRIAL REGISTRATION: The data for the present study were collected as part of a PhD thesis and the study was registered with the Clinical Trials Registry of India (CTRI/2022/12/048039).