Table 1 Baseline characteristics
From: Association of plasma mitochondrial DNA with COPD severity and progression in the SPIROMICS cohort
Parameter | Non-smokers | Smokers without airflow obstruction | Mild/Mod COPD | Severe COPD | P-value* |
|---|---|---|---|---|---|
(n = 100) | (n = 199) | (n = 201) | (n = 200) | ||
Age [IQI] | 56 [50, 65] | 61 [52, 67] | 66 [ 60, 71] | 65 [59, 71] |  < 0.001 |
Sex N (%) | Â | Â | |||
 Male | 42 (42%) | 96 (48%) | 130 (65%) | 122 (61%) |  < 0.001 |
Race N (%) |  |  < 0.001 | |||
 Asian | 3 (3.1%) | 3 (1.5%) | 5 (2.5%) | 2 (1.0%) |  |
 Black | 26 (27%) | 52 (27%) | 23 (12%) | 29 (15%) |  |
 Other | 4 (4.1) | 8 (4.1%) | 4 (2.0%) | 4 (2.0%) |  |
 White | 65 (66%) | 133 (68%) | 168 (84%) | 163 (82%) |  |
Current smoking N (%) | 0 (0%) | 98 (48%) | 77 (39%) | 40 (20%) |  < 0.001 |
FEV1% predicted [IQI] | 102 [95, 109] | 97 [86, 106] | 71 [61, 80] | 34 [27, 43] |  < 0.001 |
 6MWD [IQI] | 465 [392, 516] | 450 [390, 503] | 429 [366, 484] | 315 [249, 396] |  < 0.001 |
 CAT [IQI] | 3 [1, 8] | 9 [5, 16] | 13 [8, 20] | 19 [13, 24] |  < 0.001 |
 SGRQ [IQI] | 5 [4, 11] | 17 [8, 38] | 28 [16, 45] | 47 [39, 60] |  < 0.001 |