Introduction: Chronic hypercapnia modulates airway inflammation and can increase the risk for acute exacerbations (AE) in patients with COPD. Exacerbations in the past are associated with future flare-ups. Reducing hypercapnia with long-term non-invasive ventilation (LT-NIV) may decrease the risk for AE; however, it is unclear if patients with a high burden of AE before LT-NIV are still at higher risk for future AE post set up.    

Methods: Thirty-three (age: 64±9 yrs, 45% male) patients receiving LT-NIV were enrolled and followed up until the end of the data collection period or the death of the patient (median follow-up: 21 [IQR=3-36] months). Exacerbation history (moderate and severe events), smoking history, blood eosinophil count and capillary blood gas parameters were recorded at the time of enrolment and at follow-up visits. Treatment adherence was regularly monitored. Annualized AE rate was calculated to adjust for the different follow-up durations. Predictors of AE rate were investigated with linear regression models.

Results: The median AE rate (3 [3-5] vs. 2 [0-4] AE/year, p=0.01) and blood carbon dioxide levels (7.6 [7.0-8.8] vs. 6.5 [6.0-7.1] kPa, p<0.001) decreased significantly after the initiation on LT-NIV. 29 (88%) patients were adherent (>4 h/day usage) to the therapy. Excluding the non-adherent patients, we found that AE rate pre-setup was independently related to later events (?=0.68, p<0.01, whole model R²=0.56, p=0.04).

Conclusion: Although LT-NIV reduces the number of AEs in patients with COPD, those who had a higher burden of AEs are still at risk for developing future events.