Relationship Between FEV₁ and Patient-Reported Outcomes Changes: Results of a Meta-Analysis of Randomized Trials in...

Background: This meta-analysis assessed the relationship between change from baseline (CFB) in spirometric measurements (trough forced expiratory volume in 1 second [FEV₁] and FEV₁ area under the curve [AUC]) and patient-reported outcomes (St. George's Respiratory Questionnaire total score [SGRQ] CFB, Transition Dyspnea Index [TDI] and exacerbation rates) after 6-12 months' follow-up, using study treatment-group level data. Methods: A systematic literature search was performed for randomized controlled trials of ≥24 weeks duration in adults with chronic obstructive pulmonary disease (COPD). Studies reporting ≥1 spirometric measurement and ≥1 patient-reported outcome (PRO) at baseline and at study endpoint were selected. The relationships between PROs and spirometric endpoints were assessed using Pearson correlation coefficient and meta-regression. Results: Fifty-two studies (62,385 patients) were included. Primary weighted analysis conducted at the last assessment showed a large significant negative correlation (r, -0.68 [95% confidence interval (CI); -0.77, -0.57]) between trough FEV₁ and SGRQ. Improvement of 100 mL in trough FEV₁ corresponded to a 5.9 point reduction in SGRQ. Similarly, a reduction of 4 points on SGRQ corresponded to 40 mL improvement in trough FEV₁ (p<0.001). The weighted correlation coefficients of trough FEV₁ with TDI, exacerbation rate (all) and exacerbation rate (moderate/severe) at last assessment point were 0.57, -0.69 and -0.57, respectively (all p<0.05). For the analyses excluding placebo groups, the correlations of FEV₁ with SGRQ and TDI were lower but significant. Conclusions: A strong association exists between changes in spirometric measurements and changes in PROs.