Chest
Volume 123, Issue 5, May 2003, Pages 1416-1424
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Clinical Investigations
EXERCISE
Striking Similarities in Systemic Factors Contributing to Decreased Exercise Capacity in Patients With Severe Chronic Heart Failure or COPD

https://doi.org/10.1378/chest.123.5.1416Get rights and content

Aims:

Chronic heart failure (CHF) and COPD are both characterized by muscular impairment. To assess whether the severity and functional consequences of muscular impairment are disease specific, we compared skeletal muscle function, body composition, and daily activity level relative to exercise capacity between these two disorders.

Methods:

Twenty-five patients with CHF and 25 patients with COPD, and 36 healthy gender- and age-matched control subjects underwent measurement of fat-free mass (FFM) [by bioelectrical impedance analysis] as an index of muscle mass. Quadriceps and biceps functions were tested by isokinetic methods, and daily activity level was assessed by the Physical Activity Scale for Elderly (PASE) questionnaire. Peak oxygen consumption (

o2peak) was measured by incremental cycle ergometry.

Results:

PASE results were similar in patients with CHF and in patients with COPD, each group scoring lower than control subjects. FFM was also lower in patients than control subjects and correlated closely with quadriceps and biceps strength in all three subgroups, R values ranging from 0.63 to 0.78, with identical slopes. FFM also correlated significantly with

o2peak (p < 0.05), but slopes were less steep in patients than in control subjects. The type and severity of muscle dysfunction were similar in each group of patients. There were no significant correlations between indexes of cardiopulmonary function and muscle function or exercise performance in patients with CHF or in patients with COPD. In both control subjects and patients, FFM was the most significant determinant of
o2peak.

Conclusion:

Muscle dysfunction is not limited to the lower limbs, but generalized and comparable between patients with CHF and patients with COPD with similar exercise capacity. FFM is a strong predictor of peripheral muscle strength, to a lesser extent of

o2peak, and not at all of peripheral muscle endurance.

Section snippets

Study Population

Groups of 25 patients with COPD with moderate-to-severe airflow obstruction, 25 patients with moderate-to-severe CHF, and 36 healthy age-matched volunteers were studied. All pulmonary patients had COPD according to American Thoracic Society guidelines9 and chronic airflow limitation, defined as measured FEV1 < 70% of reference FEV1. Furthermore, patients with COPD had irreversible obstructive airway disease (< 10% improvement of FEV1 predicted baseline after β2-agonist inhalation). Patients

Subject Characteristics

Twenty-five patients with COPD (16 men and 9 women), 25 patients with CHF (17 men and 8 women), and 36 healthy control subjects (24 men and 12 women) participated in this study (Table 1). There were no differences in gender or age between the groups. Only patients with COPD had a lower BMI than control subjects; however, FFMI was reduced in patients with COPD as well as in patients with CHF compared to healthy subjects. PASE score was significantly lower in both patient groups than in control

Discussion

In the current study we demonstrate that both COPD and CHF, two distinct disorders with a comparably decreased exercise capacity, show striking similarities with respect to muscle dysfunction, loss of FFM, and reduced daily activity level when compared to age-matched healthy control subjects. We also show that peripheral skeletal muscle weakness is generalized in both disorders with upper and lower limb muscle function being equally affected. Furthermore, as in control subjects, the FFM is an

ACKNOWLEDGMENT

We thank Petra Heuts, Femke Ellens, and Dr. Matthijs Hesselink for assistance with isokinetic muscle testing.

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  • Cited by (0)

    Supported by a grant from the Netherlands Asthma Foundation (project number 96.16).

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