TABLE 1.
Clinical and demographic characteristics of the subjects included in the case-control and case-only analyses
| GALA II | SAGE | |||||
|---|---|---|---|---|---|---|
| Asthma with exacerbations (n = 1283) | Asthma without exacerbations (n = 898) | Control (n = 2027) | Asthma with exacerbations (n = 448) | Asthma without exacerbations (n = 524) | Control (n = 595) | |
| Gender (% female) | 582 (45.4)a | 403 (44.9) | 1137 (56.1) | 214 (47.8)a | 263 (50.2) | 340 (57.1) |
| Mean age in years ± SD | 12.2 ± 3.1a,b | 13.4 ± 3.5 | 13.9 ± 3.6 | 13.3 ± 3.6a,b | 14.4 ± 3.6 | 15.6 ± 3.8 |
| African ancestry (%) | 18.9 ± 13.2a,b | 12.6 ± 11.9 | 14.2 ± 12.0a | 83.6 ± 18.1 | 81.5 ± 21.5 | 81.7 ± 18.1 |
| Native American ancestry (%) | 22.9 ± 22.6b | 37.4 ± 25.5 | 33.9 ± 27.8 | NA | NA | NA |
| Asthma exacerbations in the last 12 mo, n (%) | ||||||
| Acute asthma care | 1092 (85.1) | NA | NA | 231 (51.6) | NA | NA |
| Oral corticosteroid use | 712 (55.5) | NA | NA | 337 (75.2) | NA | NA |
| Hospitalizations | 192 (15.0) | NA | NA | 88 (19.6) | NA | NA |
| Asthma control, n (%)c | ||||||
| Well controlled | 210 (16.4)b | 431 (48.0) | NA | 60 (15.7)b | 182 (36.8) | NA |
| Partially controlled | 533 (41.5)b | 282 (31.4) | NA | 112 (29.4) | 150 (30.4) | NA |
| Poorly controlled | 540 (42.1)b | 185 (20.6) | NA | 209 (54.9)b | 162 (32.8) | NA |
| Treatment category n (%)d | ||||||
| Step 1 | 464 (36.4)b | 505 (56.4) | NA | 97 (21.7)b | 242 (46.5) | NA |
| Step 2 | 417 (32.7)b | 233 (26.1) | NA | 182 (40.6) | 210 (40.3) | NA |
| Step 3 | 394 (30.9)b | 157 (17.5) | NA | 169 (37.7)b | 69 (13.2) | NA |
| Eczema, n (%)e | 224 (17.7) | 134 (15.1) | NA | 188 (48.5)b | 159 (32.4) | NA |
| Hay fever/rhinitis, n (%)f | 564 (45.2)b | 314 (35.4) | NA | 148 (36.2) | 142 (28.9) | NA |
| FEV1 (%)g | 97.9 ± 15.7a,b | 103.6 ± 14.4 | 108.0 ± 12.6 | 91.2 ± 11.9 | 92.4 ± 11.6 | 96.1 ± 10.8 |
| FVC (%)g | 102.0 ± 16.0a,b | 107.3 ± 15.3 | 108.0 ± 13.6 | 96.5 ± 11.8 | 97.0 ± 10.9 | 98.4 ± 11.8 |
| FEV1/FVC (%)g | 96.4 ± 7.6a | 97.2 ± 7.2 | 99.7 ± 6.7 | 94.1 ± 8.3 | 95.3 ± 7.6 | 97.8 ± 7.4 |
Note: For continuous variables, the mean and standard deviation are displayed, and the Mann-Whitney-Wilcoxon test was applied for the comparison of cases vs controls. For categorical variables, the number and proportion of subjects in each category are shown and a chi-square test was applied for the comparison of cases vs controls.
Abbreviations: FEV1, forced expiratory volume in the first second; FVC, forced vital capacity; NA, not available/applicable; SD, standard deviation.
P < .01 for the comparison between asthma cases with exacerbations and controls.
P < .01 for the comparison between asthma cases with exacerbations and asthma cases without exacerbations.
Asthma control was available for 2181 and 875 asthma cases from GALA II and SAGE, respectively.
The severity medication regime was categorized into three levels based on the use of short beta-agonists (step 1), one inhaled corticosteroid, leukotriene inhibitor, or theophylline tablet (step 2), more than one or a combination of an inhaled corticosteroid, leukotriene inhibitor, or theophylline tablet or a combination of inhaled corticosteroids and long-beta-agonists (step 3). Medication data were available for 2170 and 969 asthma cases from GALA II and SAGE, respectively.
Eczema status was available for 2155 and 879 subjects from GALA II and SAGE, respectively.
Hay fever status was available for 2133 and 901 subjects from GALA II and SAGE, respectively.
FEV1, FVC, and FEV1/FVC were available for 2698, 2710, and 2662 GALA II subjects, respectively, and 1058, 1075, and 1056 SAGE subjects, respectively.