Dreher M, Neuzeret PC, Windisch W, et al. - Researchers investigated the prevalence of chronic hypercapnia in COPD in an outpatient setting in a multicenter, prospective, observational, non-interventional patient registry, the HOmeVent registry. They also focused on the predictors of hypercapnia. Eligible COPD patients in GOLD stage 3 or 4 were selected and registered in an outpatient setting during routine clinic visits. Blood gas analyses, pulmonary function testing and quality of life evaluation were performed to examine the participants. Findings revealed the presence of chronic hypercapnia in a relevant proportion of COPD patients in GOLD stage 3 and 4, and thus, these patients represent candidates for long-term domiciliary non-invasive ventilation treatment. The factors that significantly and independently predicted hypercapnia were an increased body mass index, a decreased forced vital capacity, and an increased bicarbonate level.