Is FEV1 Q a good prognostic tool in COPD?

Abstract

<bold>Introduction:</bold> Several prognostic tools are used to assess COPD, notably FEV1 as a percentage of predicted value, the functional parameter on which the spirometric GOLD classification is based. The FEV1 Q proposed by the latest ATS/ERS recommendations on PFTs is defined by a FEV1/0.5 ratio in men (0.4 in women) close to 1, predictive of high mortality. <bold>Methods:</bold> This longitudinal study looked at the evolution of all COPD patients who underwent forced spirometry with bronchodilation testing in 2019. The 2019 FEV1 Q was calculated for all patients and then compared with evolving clinical parameters up to 2024. <bold>Results:</bold> During 2019, 400 forced spirometry with bronchodilation test were performed, of which 87 corresponded to COPD patients. The mean age was 54.6 ± 0.3 years, with a sex ratio of 8.66 and a mean BMI of 25.53 ±4.7 kg/m2. Smoking was present in 86 patients, 44 of whom had quit. The most common comorbidities were diabetes, arterial hypertension and coronary insufficiency. On average, COPD had been diagnosed 4 years previously (between 2 and 11 years). All patients were on background treatment, with good compliance in 58 patients. Two patients were on non-invasive ventilation and 2 on long-term oxygen therapy at home. Forced spirometry in 2019 showed a mean post-bronchodilator FEV1 (post-BD) of 60.98 ± 21%. Mean FEV1 Q was 4.29. It was inversely correlated with mMRC dyspnea (p<10-3), number of hospitalizations (p=0.001), number of emergency room visits (p=0.002) and number of deaths (p=0.004). FEV1 Q in 2019 was close to 1 in 10 patients, 8 of whom died between 2019 and 2024. <bold>Conclusion:</bold> FEV1 Q appears to be a relevant and reliable prognostic indicator. Close follow-up is necessary in patients with low FEV1 Q.