PhD Scientific Days 2023

Clinical Medicine - Posters J

Past acute exacerbations predict future relapses in patients with chronic hypercapnic COPD receiving long-term non-invasive ventilation

Text of the abstract

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.
Aims: To determine the effect of normalising hypercapnia on the annual acute exacerbation rate in severe COPD.
Methods: Fifty-six (age: 64±9 yrs, 41% 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: 21.5 [IQR=4-51] months). Exacerbation history (moderate and severe), 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 [2-5] vs. 2 [0-4] AE/year, p<0.001) and blood carbon dioxide levels (62.3±20.3 vs. 48.0±9.0 Hgmm, p<0.001) decreased significantly after the initiation on LT-NIV. 49 (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 (β=0.51, p<0.01, whole model R2=0.54, p<0.01).
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.
Funding: Balázs Csoma was supported by the SE 250+ PhD Excellence Program, the National Talent Program of the Hungarian Prime Ministry, and the Hungarian State Eötvös Scholarship of the Tempus Public Foundation.