Musculoskeletal disorders in chronic obstructive pulmonary disease

Abstract

Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction and inflammation but also accompanied by several extrapulmonary consequences, such as skeletal muscle weakness and osteoporosis. Skeletal muscle weakness is of major concern, since it leads to poor functional capacity, impaired health status, increased healthcare utilization, and even mortality, independently of lung function. Osteoporosis leads to fractures and is associated with increased mortality, functional decline, loss of quality of life, and need for institutionalization. Therefore, the presence of the combination of these comorbidities will have a negative impact on daily life in patients with COPD. In this review, we will focus on these two comorbidities, their prevalence in COPD, combined risk factors, and pathogenesis. We will try to prove the clustering of these comorbidities and discuss possible preventive or therapeutic strategies.

Figure 1

Reduced muscle strength of the quadriceps, pectoralis major, and latissimus dorsi obtained in normal subjects and patients with COPD. All three types of muscles show decreased muscle strength in patients with COPD. *P < 0.005 Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society, official journal of the American Thoracic Society [17].

Figure 2

Cross-sectional area as well as muscle force of thigh muscle was reduced in patients with COPD (b) compared to normal subject (a). Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society, official journal of the American Thoracic Society [17].

Figure 3

Survival of patients with COPD with normal and reduced quadriceps strength. The curves are significantly different P = 0.017 [24].

Figure 4

Bone mineral density in different GOLD stages. The T-score is the difference between the patient's results and the mean results obtained in a young population, expressed in units of standard deviation. Osteoporosis is the condition with a T-score below −2.5; osteopenia is the condition of a T-score between −1 and −2.5. The prevalence of low bone mineral density increases with higher GOLD stage [25].

Figure 5

Several risk factors, such as cigarette smoke, physical inactivity, inflammation and oxidative stress, corticosteroid use, hormonal disturbances, nutritional deficits, and age, lead to the development of skeletal muscle weakness and osteoporosis in healthy individuals, as well as patients with COPD. There are several therapy modalities that can be used to treat or inverse the consequences of these risk factors so that the risk of developing skeletal muscle weakness and osteoporosis can be reduced in patients with COPD.