This study aimed to (1) evaluate the association
between anxiety and depressive symptoms and HRQoL
after adjusting for potential confounders and (2) identify
the effect modifiers of this relationship. Authors
hypothesised that the relationship between anxiety and/
or depressive symptoms and HRQoL in COPD patients
could be modified by certain socio-demographic and
functional characteristics of the patients. The study
included a large sample of stable COPD patients with
mild to very severe disease, and had been designed as
an ancillary study of the larger Phenotype and Course of
COPD (PAC-COPD) project [14].