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The importance of symptoms in the longitudinal variability of clusters in COPD patients: A validation study
Author(s) -
de Torres Juan P.,
Marin Jose M.,
MartinezGonzalez Cristina,
de LucasRamos Pilar,
Cosio Borja,
Casanova Ciro
Publication year - 2018
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.13194
Subject(s) - copd , medicine , spirometry , body mass index , cluster (spacecraft) , airway , physical therapy , quality of life (healthcare) , longitudinal study , asthma , surgery , pathology , nursing , computer science , programming language
Background and objective Cluster analysis has been utilized to explore phenotypic heterogeneity in chronic obstructive pulmonary disease (COPD). To date, little is known about the longitudinal variability of clusters in COPD patients. We aimed to evaluate the 2‐year cluster variability in stable COPD patients. Methods We evaluated the following variables in COPD patients at baseline and 2 years later: age, gender, pack‐year history, body mass index (BMI), modified Medical Research Council (MMRC) scale, 6‐min walking distance (6MWD), spirometry and COPD Assessment Test (CAT). Patient classification was performed using cluster analysis at baseline and 2 years later. Each patient’s cluster variability after 2 years and its parameters associated with cluster change were explored. Results A total of 521 smokers with COPD were evaluated at baseline and 2 years later. Three different clusters were consistently identified at both evaluation times: cluster A (of younger age, mild airway limitation, few symptoms), cluster B (intermediate) and cluster C (of older age, severe airway limitation and highly symptomatic). Two years later, 70% of patients were unchanged, whereas 30% changed from one cluster to another: 20% from A to B; 15% from B to A; 15% from B to C; 42% from C to B and 8% from C to A. 6MWD, forced expiratory volume in 1 s (FEV 1 ) % and CAT were the principal parameters responsible for this change. Conclusion After 2 years of follow‐up, most of the COPD patients maintained their cluster assignment. Exercise tolerance, lung function and quality of life were the main driving parameters in those who change their cluster assignment.