Defining the « frequent exacerbator » phenotype in COPD: a hypothesis-free approach.
Chest. 2017 Oct 17;:
Authors: Le Rouzic O, Roche N, Cortot AB, Tillie-Leblond I, Masure F, Perez T, Boucot I, Hamouti L, Ostinelli J, Pribil C, Poutchnine C, Schück S, Pouriel M, Housset B
BACKGROUND: The COPD frequent exacerbator phenotype is usually defined by at least 2 treated exacerbations per year and is associated with a huge impact on patient health. However, existence of this phenotype and corresponding threshold still need to be formally confirmed by statistical methods analysing exacerbations profiles with no specific a priori hypothesis.
OBJECTIVE: To confirm the existence of the frequent exacerbator phenotype with an innovative unbiased statistical analysis of prospectively recorded exacerbations.
METHODS: Data of COPD patients from the French cohort EXACO were analysed using the KmL method designed to cluster longitudinal data and ROC curve analysis to determine the best threshold to allocate patients to identified clusters. Univariate and multivariate analyses were performed to study characteristics associated with different clusters.
RESULTS: Two clusters of patients were identified based on exacerbation frequency over time with 2.89 exacerbations per year on average in the first cluster (n=348) and 0.71 in the second (n=116). The best threshold to distinguish these clusters was 2 moderate to severe exacerbations per year. Frequent exacerbators had more airflow limitation, symptoms and health related quality of life impairment. A simple clinical score was derived to help identifying patients at risk of exacerbations.
CONCLUSIONS: These analyses confirmed the existence and clinical relevance of a frequent exacerbator subgroup of COPD patients, and the currently used threshold to define this phenotype.
PMID: 29054347 [PubMed - as supplied by publisher]