title: Components of physical capacity in patients with chronic obstructive pulmonary disease: relationship with phenotypic expression.
abstract: BACKGROUND
  More accurate phenotyping of COPD is of great interest since it may have prognostic and therapeutic consequences. We attempted to explore the possible relationship between the extent of emphysema, as assessed by high-resolution computed tomography (HRCT), and COPD severity. We also included some study variables involving exercise tolerance evaluation and peripheral muscle strength (PMS) measurement.
  
  
  METHODS
  Sixty-four patients with COPD (mean age 64 ± 7 years) were enrolled in a prospective observational cross-sectional study. All patients underwent clinical and functional evaluations: assessment of dyspnea, body mass index (BMI), health status assessment, spirometry testing, and arterial blood gas analysis. The extent of emphysema was graded using HRCT. Functional capacity was evaluated by a cardiopulmonary maximal exercise testing (CPET), the shuttle walking test, and by estimation of PMS.
  
  
  RESULTS
  Half of the study patients had an emphysematous phenotype. There was a significant correlation between the score derived from analysis of HRCT images and BMI and respiratory functional parameters, as well as VO(2) max (maximal oxygen uptake) and chest pull 1RM (1 rep max). Compared with subjects with a non-emphysematous phenotype, those with an emphysematous phenotype showed a lower BMI, a reduced PMS, and displayed a lower power at CPET. Significant differences in lung function tests were found for diffusing capacity and hyperinflation. No significant differences in quality of life were observed between the two study groups.
  
  
  CONCLUSIONS
  Compared with subjects with a non-emphysematous phenotype, subjects with an emphysematous phenotype has a different profile in terms of BMI, lung function, PMS, and exercise capacity.
authors.affiliation: Medical-Surgical Unit of Respiratory Diseases, University Hospital Virgen del Rocío, Seville, Spain. eduardo.marquez.sspa@juntadeandalucia.es
authors.forename: Eduardo
authors.initials: E
authors.lastname: Márquez-Martín
authors.forename: Pilar Cejudo
authors.initials: PC
authors.lastname: Ramos
authors.forename: José Luis
authors.initials: JL
authors.lastname: López-Campos
authors.forename: María del Pilar
authors.initials: Mdel P
authors.lastname: Serrano Gotarredona
authors.forename: Silvia Navarro
authors.initials: SN
authors.lastname: Herrero
authors.forename: Rodrigo Tallón
authors.initials: RT
authors.lastname: Aguilar
authors.forename: Emilia Barrot
authors.initials: EB
authors.lastname: Cortes
authors.forename: Francisco Ortega
authors.initials: FO
authors.lastname: Ruiz
mesh_terms: D000368:Aged; D001784:Blood Gas Analysis; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005080:Exercise Test; D017079:Exercise Tolerance; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010641:Phenotype; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D011788:Quality of Life; D012720:Severity of Illness Index; D013030:Spain; D013147:Spirometry; D014057:Tomography, X-Ray Computed