Elena Tejero1, Eva Prats2, Raquel Casitas3,4,5, Raúl Galera3,4,5, Paloma Pardo1, Adelaida Gavilán2, Elisabet Martínez-Cerón3,4,5, Carolina Cubillos-Zapata4,5, Luis Del Peso4,5,6,7, Francisco García-Río3,4,5,8. 1. 1 Servicio de Urgencias and. 2. 2 Unidad de Neumología, Hospital Universitario de Fuenlabrada, Fuenlabrada, Madrid, Spain. 3. 3 Servicio de Neumología and. 4. 4 Instituto de Investigación Sanitaria, Hospital Universitario La Paz, Madrid, Spain. 5. 5 Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. 6. 6 Departamento de Bioquímica and. 7. 7 Instituto de Investigaciones Biomédicas "Alberto Sols," Madrid, Spain. 8. 8 Departamento de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; and.
Abstract
RATIONALE: Global Lung Function Initiative recommends reporting lung function measures as z-score, and a classification of airflow limitation (AL) based on this parameter has recently been proposed. OBJECTIVES: To evaluate the prognostic capacity of the AL classifications based on z-score or percentage predicted of FEV1 in patients with chronic obstructive pulmonary disease (COPD). METHODS: A cohort of 2,614 patients with COPD recruited outside the hospital setting was examined after a mean (± SD) of 57 ± 13 months of follow-up, totaling 10,322 person-years. All-cause mortality was analyzed, evaluating the predictive capacity of several AL staging systems. MEASUREMENTS AND MAIN RESULTS: Based on Global Initiative for Chronic Obstructive Lung Disease guidelines, 461 patients (17.6%) had mild, 1,452 (55.5%) moderate, 590 (22.6%) severe, and 111 (4.2%) very severe AL. According to z-score classification, 66.3% of patients remained with the same severity, whereas 23.7% worsened and 10.0% improved. Unlike other staging systems, patients with severe AL according to z-score had higher mortality than those with very severe AL (increase of risk by 5.2 and 3.9 times compared with mild AL, respectively). The predictive capacity for 5-year survival was slightly higher for FEV1 expressed as percentage of predicted than as z-score (area under the curve: 0.714-0.760 vs. 0.649-0.708, respectively). A severity-dependent relationship between AL grades by z-score and mortality was only detected in patients younger than age 60 years. CONCLUSIONS: In patients with COPD, the AL classification based on z-score predicts worse mortality than those based on percentage of predicted. It is possible that the z-score underestimates AL severity in patients older than 60 years of age with severe functional impairment.
RATIONALE: Global Lung Function Initiative recommends reporting lung function measures as z-score, and a classification of airflow limitation (AL) based on this parameter has recently been proposed. OBJECTIVES: To evaluate the prognostic capacity of the AL classifications based on z-score or percentage predicted of FEV1 in patients with chronic obstructive pulmonary disease (COPD). METHODS: A cohort of 2,614 patients with COPD recruited outside the hospital setting was examined after a mean (± SD) of 57 ± 13 months of follow-up, totaling 10,322 person-years. All-cause mortality was analyzed, evaluating the predictive capacity of several AL staging systems. MEASUREMENTS AND MAIN RESULTS: Based on Global Initiative for Chronic Obstructive Lung Disease guidelines, 461 patients (17.6%) had mild, 1,452 (55.5%) moderate, 590 (22.6%) severe, and 111 (4.2%) very severe AL. According to z-score classification, 66.3% of patients remained with the same severity, whereas 23.7% worsened and 10.0% improved. Unlike other staging systems, patients with severe AL according to z-score had higher mortality than those with very severe AL (increase of risk by 5.2 and 3.9 times compared with mild AL, respectively). The predictive capacity for 5-year survival was slightly higher for FEV1 expressed as percentage of predicted than as z-score (area under the curve: 0.714-0.760 vs. 0.649-0.708, respectively). A severity-dependent relationship between AL grades by z-score and mortality was only detected in patients younger than age 60 years. CONCLUSIONS: In patients with COPD, the AL classification based on z-score predicts worse mortality than those based on percentage of predicted. It is possible that the z-score underestimates AL severity in patients older than 60 years of age with severe functional impairment.
Authors: William Z Zhang; Kazunori Gomi; Seyed Babak Mahjour; Fernando J Martinez; Renat Shaykhiev Journal: Am J Respir Crit Care Med Date: 2018-06-15 Impact factor: 21.405
Authors: Kate Petrie; Brett G Toelle; Richard Wood-Baker; Graeme P Maguire; Alan L James; Michael Hunter; David P Johns; Guy B Marks; Johnson George; Michael J Abramson Journal: Int J Chron Obstruct Pulmon Dis Date: 2021-02-25