title: Subtypes of patients experiencing exacerbations of COPD and associations with outcomes.
abstract: Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous condition characterized by occasional exacerbations. Identifying clinical subtypes among patients experiencing COPD exacerbations (ECOPD) could help better understand the pathophysiologic mechanisms involved in exacerbations, establish different strategies of treatment, and improve the process of care and patient prognosis. The objective of this study was to identify subtypes of ECOPD patients attending emergency departments using clinical variables and to validate the results using several outcomes. We evaluated data collected as part of the IRYSS-COPD prospective cohort study conducted in 16 hospitals in Spain. Variables collected from ECOPD patients attending one of the emergency departments included arterial blood gases, presence of comorbidities, previous COPD treatment, baseline severity of COPD, and previous hospitalizations for ECOPD. Patient subtypes were identified by combining results from multiple correspondence analysis and cluster analysis. Results were validated using key outcomes of ECOPD evolution. Four ECOPD subtypes were identified based on the severity of the current exacerbation and general health status (largely a function of comorbidities): subtype A (n = 934), neither high comorbidity nor severe exacerbation; subtype B (n = 682), moderate comorbidities; subtype C (n = 562), severe comorbidities related to mortality; and subtype D (n = 309), very severe process of exacerbation, significantly related to mortality and admission to an intensive care unit. Subtype D experienced the highest rate of mortality, admission to an intensive care unit and need for noninvasive mechanical ventilation, followed by subtype C. Subtypes A and B were primarily related to other serious complications. Hospitalization rate was more than 50% for all the subtypes, although significantly higher for subtypes C and D than for subtypes A and B. These results could help identify characteristics to categorize ECOPD patients for more appropriate care, and help test interventions and treatments in subgroups with poor evolution and outcomes.
authors.affiliation: Departamento de Matemática Aplicada y Estadística e I. O, Universidad del País Vasco UPV/EHU, Leioa, Bizkaia, Spain; Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Arostegui
authors.affiliation: Servicio de Neumología, Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain; Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain.
authors.forename: Cristobal
authors.initials: C
authors.lastname: Esteban
authors.affiliation: Servicio de Epidemiología Clínica, Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain; Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: García-Gutierrez
authors.affiliation: Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain; Unidad de Epidemiología Clínica, Corporación Parc Tauli, Barcelona, Spain.
authors.forename: Marisa
authors.initials: M
authors.lastname: Bare
authors.affiliation: Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain; Subdirección General de Tecnología e Innovación Sanitarias, Consejería de Sanidad de la Comunidad de Madrid, Madrid, Spain.
authors.forename: Nerea
authors.initials: N
authors.lastname: Fernández-de-Larrea
authors.affiliation: Distrito Sanitario Atención Primaria, Sevilla, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Briones
authors.affiliation: Servicio de Epidemiología Clínica, Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain; Red de Investigación en Servicios de Salud en Enfermedades Crónicas (REDISSEC), Galdakao, Bizkaia, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Quintana
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000175:diagnosis*; D013030:Spain