Fig 1.
Map of clusters and distribution of patients.
Map created by the first and second components derived from the MCA is shown at the center. Four circles at the sides show how patients move between clusters after one year of follow-up. Relative positions of the subjects in the planes are represented by different colors, depending on the subtype provided by the cluster analysis. Definition of the axes is suggested based on information provided in appendix Table A1. The horizontal axis, first component, can be defined as an index of the respiratory conditions of the patient, milder (left side) vs. more severe (right side). The vertical axis, second component, can be defined as an index of the systemic status, worse (bottom) vs. better (top).
Fig 2.
Partial dendrogram obtained from the cluster analysis.
The dendogram represents the results from the cluster analysis performed with the four components obtained from the multiple correspondence analysis. The graphical display includes an easy interpretation of the partition and a brief description of the resulting clusters.
Table 1.
Distribution of the main clinical and functional variables related to clusters at baseline.
Table 2.
Distribution of the comorbidity variables related to clusters at baseline.
Table 3.
Association of cluster-based classification to GOLD classification and COPD severity score (HADO-AH, BODE and ADO).
Table 4.
Mortality rate, hospitalizations and HRQoL for patients with COPD exacerbation based on the clusters at baseline (1 year period) and based on the clusters transition for a 1 year period.
Fig 3.
Kaplan-Meier estimate of the survival function during the one year period of follow-up stratified by cluster.
Log-rank test for homogeneity (p < 0.001). Significant differences adjusted for multiple comparisons (Bonferroni) were observed between clusters A and C; A and D; and B and D.