Global muscle dysfunction as a risk factor of readmission to hospital due to COPD exacerbations

Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with several modifiable (sedentary life-style, smoking, malnutrition, hypoxemia) and non-modifiable (age, co-morbidities, severity of pulmonary function, respiratory infections) risk factors. We hypothesise that most of these risk factors may have a converging and deleterious effects on both respiratory and peripheral muscle function in COPD patients.

A multicentre study was carried out in 121 COPD patients (92% males, 63 ± 11 yr, FEV(1), 49 ± 17%pred). Assessments included anthropometrics, lung function, body composition using bioelectrical impedance analysis (BIA), and global muscle function (peripheral muscle (dominant and non-dominant hand grip strength, HGS), inspiratory (PI(max)), and expiratory (PE(max)) muscle strength). GOLD stage, clinical status (stable vs. non-stable) and both current and past hospital admissions due to COPD exacerbations were included as covariates in the analyses.

Respiratory and peripheral muscle weakness were observed in all subsets of patients. Muscle weakness, was significantly associated with both current and past hospitalisations. Patients with history of multiple admissions showed increased global muscle weakness after adjusting by FEV(1) (PE(max), OR = 6.8, p < 0.01; PI(max), OR = 2.9, p < 0.05; HGSd, OR = 2.4, and HGSnd, OR = 2.6, p = 0.05). Moreover, a significant increase in both respiratory and peripheral muscle weakness, after adjusting by FEV(1), was associated with current acute exacerbations.

Muscle dysfunction, adjusted by GOLD stage, is associated with an increased risk of hospital admissions due to acute episodes of exacerbation of the disease. Current exacerbations further deteriorate muscle dysfunction.