engleski

Bone health of patients with COPD in relation to their exercise capacity and gait speed

Background: Osteoporosis is an important extra- pulmonary manifestation of chronic obstructive pulmonary disease (COPD). Aim: To evaluate the prevalence of osteoporosis, osteopenia and vitamin D deficiency in patients with moderate to very severe COPD, and to explore the association between bone mineral density (BMD) and exercise capacity / gait speed. Methods: BMD and T-score were measured by the dual energy X-ray absorptiometry, and serum level of 25-hydroxyvitamin D was determined. Severity of COPD was evaluated by the pulmonary functions tests, COPD Assessment Test, and modified Medical Research dyspnoea scale. Six- minute walk distance (6MWD) and 4-metre gait speed (4MGS) test were used in the assessment of physical fitness. Results: In 111 patients (male 76, mean age 68 years, forced expiratory volume in 1 second 48.9±15 % predicted) the mean BMD was 1.1±0.1 g/cm2, and T-score -1.0±1.5. Osteoporosis (T- score <-2.5) was established in 14 patients (12.6%), and osteopenia (T-score of -1 to -2.5) in 45 patients (40.5%). Vitamin D insufficiency (serum concentration 50-75 nmol/L) was found in 105 patients (94.6%) with 86 (77.5%) being vitamin D deficient (<50 nmol/L). Patients with reduced exercise capacity (6MWD ≤350m) had significantly lower BMD (1.07±0.1 g/cm2, p=0.002) and smaller T-score (-1.4±1.4, p=0.013). Similarly, BMD and T-score were also significantly lower in patients with slow gait speed (4MGS <0.8 m/s), 1.05±0.1 g/cm2 (p=0.002) and -1.5±1.4 (p=0.017), respectively. Conclusion: High proportion of COPD patients have reduced BMD and low vitamin D levels. Poor bone health is associated with impaired physical performance.

Osteoporosis, COPD, osteopenia, bone mineral density, vitamin D deficiency

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