Mass of intercostal muscles associates with risk of multiple exacerbations in COPD.
BACKGROUND
The potential role of decreased respiratory muscle mass, if any, in mediating the susceptibility to exacerbation in COPD patients has not been determined. We hypothesized that a decrease in respiratory muscle mass is associated with increased risk of multiple hospital admissions due to acute exacerbations of the disease.


METHODS
Eligible cases and controls (n=20) were identified from records of our department's pulmonary clinic. Ten subjects diagnosed with COPD (males, 66+/-7yr, Body Mass Index (BMI)=26+/-4kg/m(2)) were identified as fragile patients. Fragility was defined as four or more admissions in the previous year due to severe exacerbations of the disease. Fragile patients were matched with 10 non-fragile controls, defined as COPD patients who had required only one admission due to exacerbation of the disease. Criteria for 1:1 matching included ethnicity, gender, age, BMI, degree of airflow obstruction (i.e., FEV(1)), comorbidity and chronic treatment. Multiple computed tomography (CT) scan slices were obtained to assess area and attenuation coefficients of multiple upper limb, thorax, abdomen and lower limb muscles.


RESULTS
CSA of intercostal and abdominal muscles was significantly decreased in fragile COPD patients (right side intercostals, mean relative difference (MRD)=-14%, p=0.010; OR (95% CI)=2.2 (1.1-4.8), p=0.021; left side, MRD=-13%, p=0.007; OR=2.2 (1.1-4.5), p=0.027). CSA and attenuation coefficients of all other muscle compartments showed no statistical differences between the two study groups but showed the same trend. Strength of the inspiratory and expiratory muscles did not differ between the two study groups.


CONCLUSIONS
This study shows that the risk for multiple admissions due to a COPD exacerbation associates with a marked decrease in the CSA of the intercostal muscle compartment.
Güerri
Roberto
R
Servei de Medicina Interna, Hospital del Mar, Barcelona, Spain.
Gayete
Angel
A
Balcells
Eva
E
Ramirez-Sarmiento
Alba
A
Vollmer
Ivan
I
Garcia-Aymerich
Judith
J
Gea
Joaquim
J
Orozco-Levi
Mauricio
M
D000009:Abdominal Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology; D000368:Aged; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D018450:Disease Progression; D017079:Exercise Tolerance; D006801:Humans; D007366:Intercostal Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D011859:Radiography; D012307:Risk Factors; D016896:Treatment Outcome
D001993:Bronchodilator Agents