Mucus plugs tied to higher sarcopenia risk, lower muscle, fat mass

Airway mucus plugs appear to reduce muscle and fat mass and increase sarcopenia risk in patients with chronic obstructive pulmonary disease (COPD) and pre-COPD, according to a study.

In this cross-sectional analysis, the authors classified patients with COPD and pre-COPD into no-, low-, and high-mucus groups based on their mucus scores on computed tomography (CT). They also compared the risks of frailty and sarcopenia, as well as relevant clinical, functional, and imaging factors including 6-min walk distance (6WMD), physical activity, body compositions via bioelectrical impedance analysis (BIA), and intra- and extrapulmonary CT indices, between groups.

Of the 175 eligible patients (142 COPD and 33 pre-COPD), 106 were in the no-mucus group, 48 in the low-mucus group, and 21 in the high-mucus group. Those in the high-mucus group were at greater risk of sarcopenia independent of age, sex, height, smoking, and forced expiratory volume in 1 s, or emphysema and wall area percentage (WA%).

Furthermore, the high-mucus group had increased airstrapping and WA%, reduced total airway count, and reduced muscle and fat mass (assessed by both BIA and CT). Emphysema did not differ across groups. High-mucus patients also exhibited a decreased 6MWD regardless of age, sex, height, and smoking. Physical activity showed no significant difference.

“Airway mucus plugs on CT are an imaging biomarker of COPD associated with airflow limitation, respiratory symptoms, and poor prognosis,” the authors said. “However, clinical phenotypes relevant to mucus plugs, including sarcopenia and frailty, are not fully elucidated.”