BackgroundMultiple 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. ObjectiveTo evaluate the different factors that can influence the activity and
psychosocial impact domains of the Saint George's Respiratory Questionnaire
(SGRQ) in COPD patients. MethodParticipants, 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. ResultsThe 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. ConclusionsThe 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.