A cluster analysis of chronic obstructive pulmonary disease in dusty areas cohort identified three subgroups

BMC Pulmonary Medicine

Table 1 Correlations of the 15 original variables with the six main factors derived from the factor analysis in the 272 COPD subjects

	Factor 1	Factor 2	Factor 3	Factor 4	Factor 5	Factor 6
Eigenvalue	3.380	2.152	1.654	1.391	1.341	1.164
% variance explained	25.936	14.346	11.028	9.273	8.974	7.762
Pre FVC, %	.971	−.052	.072	−.035	−.149	.003
Post FVC, %	.924	.079	.029	−.026	−.049	−.009
Pre FEV1, %	.924	−.008	−.048	.004	.038	−.029
Post FEV1, %	.918	.027	−.048	.009	.097	.003
PMN	.032	.969	−.008	.080	−.002	−.064
WBC	.010	.959	−.027	−.005	.079	.125
mMRC	.046	−.057	.936	.015	.032	.024
CAT total score	−.037	.023	.908	.007	−.013	−.023
CRP	−.055	.059	−.015	.864	.034	−.098
IL-6	.001	.030	.042	.820	−.213	−.054
BMI	−.093	.124	.137	−.081	.866	−.014
Emphysema index	−.027	.063	.167	.081	−.696	.146
Eosinophils	−.004	.082	.092	−.190	−.037	.772
Pack-year	−.093	.037	−.130	−.049	−.292	.601
Uric acid	.094	−.149	−.022	.329	.325	.556

FEV ₁ forced expiratory volume in one second, FVC forced vital capacity, PMN polymorphonuclear neutrophil, mMRC modified Medical Research Council Dyspnea Scale, CAT COPD Assessment Test, BMI body mass index
Significant factor scores are italicized

ISSN: 1471-2466