Predictors of lung function deterioration in COPD

Abstract

Introduction: The course of chronic obstructive pulmonary disease (COPD) is heterogeneous, ranging from stable disease to accelerated deterioration of lung function over time. Exhaustive identification of factors that can predict decline in lung function is still a challenge. Aim of the study: To assess annual decline in forced expiratory volume in 1-second (FEV1) and to identify predictors of lung function deterioration. Methods: In this longitudinal cohort study we enrolled outpatients with stable COPD who were followed up in a tertiary referral center from January 2010 to December 2015. Each participant had at least three spirometries during the study period. COPD was defined as post-bronchodilator (BD) FEV1/forced vital capacity (FVC) of Results: A total of 109 patients with COPD participated (77% male, mean age 67 years). Over a mean follow up of 4 years, 23 patients (21.1%) were hospitalized due to COPD, 39 (35.7 %) experienced more than two exacerbations and 5(4.5%) died. Mean (SE) annual change in FEV1 was - 37.7 ml (13.2).Patients with an estimated decline in FEV1 of more than 40 ml per year (labeled as “decliners”; n=51, 47%), had better lung function at baseline (median baseline FEV1 [IQR]:1260 ml [645] vs 1190 ml [470];p 0.04).Rate of decline in FEV1 was greater in patients with initial GOLD stages I and II (median values [IQR]: -65 ml [159] vs -20 ml [IQR 74];p 0.01) and in those who experienced incident exacerbations ( -75ml [165] vs -33ml [85];p 0.03). Multivariable analysis showed that GOLD stage I-II was a strong independent predictor of FEV1 decline ( RR 4.8, CI 95% 1.07-21.6, p 0.04). Conclusions: These findings strengthen the importance of strict surveillance in the early stages of COPD.