Inspiratory muscle strength and walking capacity in patients with COPD

• Published in: European clinical respiratory journal 2020-01, Vol.7 (1), p.1700086-1700086
• Main Authors: Kofod, Linette Marie, Hage, Tine, Christiansen, Lene Houmann, Skalkam, Karin, Martinez, Gerd, Godtfredsen, Nina Skavlan, Molsted, Stig
• Format: Article
• Language: English
• Subjects: Chronic obstructive pulmonary disease; Maximal inspiratory strength; physiotherapy; quadriceps strength; walking distance
• ISSN: 2001-8525; 2001-8525
• DOI: 10.1080/20018525.2019.1700086

Purpose: It has been suggested that patients with inspiratory muscle weakness could benefit from specific inspiratory muscle training (IMT). We aimed to examine the frequency of patients with inspiratory muscle weakness in a Danish hospital-based outpatient pulmonary rehabilitation program, and to evaluate the association between inspiratory muscle strength and peripheral muscle strength and walking capacity. Methods: Maximal Inspiratory Pressure (MIP) was assessed in 97 patients with COPD (39 men, 58 women, mean age years 70 ± 9, forced expiratory volume in 1 s ((FEV 1 ) = 35 ± 10% pred.). The impact of MIP on knee-extension strength, walking distance, and symptom burden was evaluated using multiple linear regression analyses. Results: The MIP of the patients with COPD was 63 (95% CI 59; 67) cmH 2 O and it was significantly reduced compared to gender and age-matched reference values 76 (95% CI 73; 79) cmH 2 O (p < 0.001). Seven patients (7.2%) were under the lower limit of normal. MIP was negatively correlated with increasing age, female gender, decreasing knee-extension strength and lower FEV 1 % pred. Walking distance was associated with knee-extension strength and it was not associated with MIP. Conclusion: Maximal inspiratory pressure was reduced in patients with COPD but only a few patients had a weak MIP. Whilst MIP was associated with leg muscle strength, it was not associated with walking distance or symptoms.