title: Functional outcomes in patients with chronic obstructive pulmonary disease: a multivariate analysis.
abstract: BACKGROUND
  Multiple factors can influence the severity of chronic obstructive pulmonary disease (COPD) and the functioning of patients with COPD, such as personal characteristics and systemic manifestations.
  
  
  OBJECTIVE
  To evaluate the different factors that can influence the activity and psychosocial impact domains of the Saint George's Respiratory Questionnaire (SGRQ) in COPD patients.
  
  
  METHODS
  Participants, recruited in a university-based hospital, responded to the SGRQ, and in addition, personal, anthropometric, and clinical data were collected. The study was approved by the Institutional Ethics Committee. Data were analyzed using multiple linear regression models, with the SGRQ activity and psychosocial impact scores as outcome variables, and 10 explanatory variables (age, gender, forced expiratory volume in the first second - FEV1, smoking load, body mass index, oxygen therapy, associated diseases, regular physical activity, participation in a formal rehabilitation program, and SGRQ symptoms score) were considered.
  
  
  RESULTS
  The best regression model for predicting the SGRQ activity score (r2=0.477) included gender, FEV1, and SGRQ symptoms. In contrast, the predictive model with the highest proportion of explained variance in psychosocial impact score (r2=0.426) included the variables gender, oxygen therapy, and SGRQ symptoms.
  
  
  CONCLUSIONS
  The results indicate that the outcomes, while based on functioning parameters in COPD patients, could be partly explained by the personal and clinical factors analyzed, especially by the symptoms assessed by the SGRQ. Thus, it appears that the health conditions of these patients cannot be described by isolated variables, including pulmonary function parameters.
authors.affiliation: Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Filipe T S
authors.initials: FT
authors.lastname: Athayde
authors.affiliation: Physical Therapy Department, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Danielle S R
authors.initials: DS
authors.lastname: Vieira
authors.affiliation: Physical Therapy Department, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Raquel R
authors.initials: RR
authors.lastname: Britto
authors.affiliation: Physical Therapy Department, UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Verônica F
authors.initials: VF
authors.lastname: Parreira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life; D011795:Surveys and Questionnaires