Table 2:
Baseline Characteristics of Participants according to Visual Grades of Emphysema
| Visual Grades | Absent | Trace | Mild | Moderate | Confluent | ADE | P Value* |
|---|---|---|---|---|---|---|---|
| No. of participants (n = 4166) | 1641 (39) | 771 (19) | 812 (20) | 547 (13) | 290 (7) | 105 (3) | |
| Demographic Information and Race | |||||||
| Age (y) | 58 ± 9 | 59 ± 9 | 60 ± 9 | 63 ± 8 | 65 ± 7 | 66 ± 7 | <.001 |
| Height (cm)† | 170 ± 9 | 170 ± 10 | 170 ± 10 | 169 ± 10 | 168 ± 10 | 169 ± 10 | .004 |
| Weight (kg)† | 88 ± 20 | 86 ± 20 | 81 ± 18 | 79 ± 17 | 77 ± 18 | 75 ± 17 | <.001 |
| BMI (kg/m2)† | 31 ± 6 | 30 ± 6 | 28 ± 6 | 28 ± 5 | 27 ± 5 | 26 ± 5 | <.001 |
| No. of men | 776 (47) | 405 (53) | 435 (54) | 277 (51) | 142 (49) | 56 (53) | .04 |
| No. of non-Hispanic White participants | 1206 (74) | 517 (67) | 566 (70) | 388 (71) | 241 (83) | 92 (88) | <.001 |
| No. of African-American participants | 435 (27) | 254 (33) | 246 (30) | 159 (29) | 49 (17) | 13 (12) | <.001 |
| Smoking status | |||||||
| No. of current smokers | 645 (39) | 397 (52) | 429 (53) | 247 (45) | 49 (17) | 11 (11) | <.001 |
| Smoking history (pack-year)† | 35 ± 20 | 40 ± 22 | 46 ± 23 | 51 ± 24 | 56 ± 29 | 58 ± 27 | <.001 |
| Comorbidities | |||||||
| No. of exacerbations in previous year‡ | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (1) | 0 (1) | <.001 |
| No. of participants with chronic bronchitis | 192 (12) | 109 (14) | 152 (19) | 116 (21) | 59 (20) | 14 (13) | |
| Spirometry | |||||||
| FEV1 (predicted %)† | 90 ± 17 | 84 ± 19 | 80 ± 21 | 70 ± 23 | 57 ± 23 | 46 ± 22 | <.001 |
| FEV1-to-FVC ratio† | 0.8 ± 0.1 | 0.7 ± 0.1 | 0.7 ± 0.1 | 0.6 ± 0.1 | 0.5 ± 0.1 | 0.4 ± 0.1 | <.001 |
| GOLD stage | |||||||
| No. of participants with PRISm | 247 (15) | 132 (17) | 80 (10) | 31 (6) | 5 (2) | 0 (0) | |
| No. of participants with GOLD 0 | 1126 (69) | 408 (53) | 347 (43) | 119 (22) | 15 (5) | 1 (1) | |
| No. of participants with GOLD 1 | 90 (6) | 71 (9) | 98 (12) | 86 (16) | 34 (12) | 6 (6) | |
| No. of participants with GOLD 2 | 148 (9) | 115 (15) | 207 (26) | 187 (34) | 108 (37) | 33 (31) | |
| No. of participants with GOLD 3 | 26 (2) | 44 (6) | 70 (9) | 109 (20) | 102 (35) | 35 (33) | |
| No. of participants with GOLD 4 | 4 (0) | 1 (0) | 10 (1) | 15 (3) | 26 (9) | 30 (29) | |
| 6-minute walk (ft)† | 1516 ± 357 | 1441 ± 368 | 1426 ± 343 | 1362 ± 358 | 1291 ± 352 | 1198 ± 337 | <.001 |
| MMRC‡ | 0 (1) | 0 (2) | 1 (2) | 1 (3) | 2 (2) | 3 (2) | <.001 |
| SGRQ‡ | 9 (22) | 15 (27) | 17 (32) | 26 (34) | 33 (28) | 36 (24) | <.001 |
| Emphysema (%LAA–950insp)† | 2.4 ± 3.2 | 2.5 ± 3.7 | 3.8 ± 5.1 | 8.1 ± 7.4 | 19.2 ± 10.6 | 30.5 ± 10.9 | <.001 |
| Gas trapping (%LAA–856exp)† | 11.7 ± 9.9 | 13.6 ± 11.9 | 19.1 ± 14.9 | 29.0 ± 18.1 | 42.5 ± 18.5 | 55.4 ± 14.1 | <.001 |
Note.—Except where indicated, data are numbers of patients, with percentages in parentheses. ADE = advanced destructive emphysema, BMI = body mass index, FEV1 = force expiratory volume in 1 second, FVC = forced vital capacity, GOLD = Global Initiative for Chronic Obstructive Lung Disease, MMRC = Modified Medical Research Council, %LAA−950insp = percentage of lung volume with attenuation less than −950 HU at inspiration, %LAA−856exp = percentage of lung volume with attenuation less than −856 HU at expiration, PRISm = preserved ratio impaired spirometry, SGRQ = St George’s Respiratory Questionnaire.
P values are for differences across emphysema grades, calculated with the χ2 test for categoric variables and with the F test from analysis of variance for continuous variables. The Kruskall-Wallis test was used for variables displayed as medians and interquartile ranges.
Numbers are means ± standard deviations.
Numbers are medians, with interquartile ranges in parentheses.