Chronic Obstructive Pulmonary Disease Subtypes. Transitions over Time.
BACKGROUND
Although subtypes of chronic obstructive pulmonary disease are recognized, it is unknown what happens to these subtypes over time. Our objectives were to assess the stability of cluster-based subtypes in patients with stable disease and explore changes in clusters over 1 year.


METHODS
Multiple correspondence and cluster analysis were used to evaluate data collected from 543 stable patients included consecutively from 5 respiratory outpatient clinics.


RESULTS
Four subtypes were identified. Three of them, A, B, and C, had marked respiratory profiles with a continuum in severity of several variables, while the fourth, subtype D, had a more systemic profile with intermediate respiratory disease severity. Subtype A was associated with less dyspnea, better health-related quality of life and lower Charlson comorbidity scores, and subtype C with the most severe dyspnea, and poorer pulmonary function and quality of life, while subtype B was between subtypes A and C. Subtype D had higher rates of hospitalization the previous year, and comorbidities. After 1 year, all clusters remained stable. Generally, patients continued in the same subtype but 28% migrated to another cluster. Together with movement across clusters, patients showed changes in certain characteristics (especially exercise capacity, some variables of pulmonary function and physical activity) and changes in outcomes (quality of life, hospitalization and mortality) depending on the new cluster they belonged to.


CONCLUSIONS
Chronic obstructive pulmonary disease clusters remained stable over 1 year. Most patients stayed in their initial subtype cluster, but some moved to another subtype and accordingly had different outcomes.
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.|Health Services Research on Chronic Patients Network (REDISSEC), Galdakao, Bizkaia, Spain.
Cristóbal
C
Esteban
Health Services Research on Chronic Patients Network (REDISSEC), Galdakao, Bizkaia, Spain.|Department of Applied Mathematics, Statistics and Operative Research, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain.|Basque Center for Applied Mathematics (BCAM), Leioa, Bizkaia, Spain.
Inmaculada
I
Arostegui
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Myriam
M
Aburto
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Javier
J
Moraza
Health Services Research on Chronic Patients Network (REDISSEC), Galdakao, Bizkaia, Spain.|Research Unit, Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
José M
JM
Quintana
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Amaia
A
García-Loizaga
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Luis V
LV
Basualdo
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Amaia
A
Aramburu
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Susana
S
Aizpiri
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Ane
A
Uranga
Respiratory Department. Hospital Galdakao-Usansolo, Galdakao, Bizkaia, Spain.
Alberto
A
Capelastegui
D000368:Aged; D016000:Cluster Analysis; D015897:Comorbidity; D004417:Dyspnea / Q000503:physiopathology; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life