Changes in functional respiratory imaging (FRI) endpoints correlate with changes in patient reported outcomes (PRO) after recovering from acute COPD exacerbation

Abstract

Although COPD exacerbations are an accepted endpoint in clinical trials, episodes of exacerbation remain a poorly understood phenomenon. Aims: We aim to increase our understanding of the pathophysiology of COPD exacerbations using HRCT-based FRI and to explore the relationship with PROs. Methods: 50 COPD patients were studied during an episode of acute exacerbation. FRI endpoints, PFT parameters and PRO measures were obtained during the episode and 6-8 weeks after recovery. Results: We observed that changes in FRI based airway resistance (iRaw) measured at FRC were significantly correlated with changes in SGRQ Total (R=0.37, p=0.016), SGRQ Activity (R=0.49, p=0.001, figure 1), SGRQ Symptoms (R=0.4, p=0.009), CAT (R=0.32, p=0.042) and mMRC (R=0.39, p=0.012). Changes in FRI based specific airway volume (siVaw) measured at FRC was significantly correlated with the changes in SGRQ Total (R=0.36, p=0.019), SGRQ Activity (R=0.48, p=0.001), SGRQ Symptoms (R=0.45, p=0.002), CAT (R=0.39, p=0.011) and mMRC (R=0.37, p=0.014). In this cohort changes in FEV1 correlated significantly with changes in SGRQ Activity (R=0.32, p=0.037) and in CAT (R=0.37, p=0.01) and mMRC (R=0.32, p=0.035). Conclusions: Changes in FRI based airway volume and resistances correlate better with PRO than conventional endpoints such as FEV1.