TABLE 2.
COMPARISON OF ASTHMA CHARACTERISTICS IN OVERALL COHORT AND AMONG PHENOTYPIC CLUSTERS
| Variable | All (n=154) | Cluster 1 (n=57) | Cluster 2 (n=33) | Cluster 3 (n=58) | P Value* |
|---|---|---|---|---|---|
| Sex†, % male | 59 | 81 | 30 | 53 | <0.001 |
| Age, yr (SE) | 11.5 (0.3) | 11.3 (0.6) | 13.8 (0.6) | 10.5 (0.5) | <0.001 |
| Age of onset†, yr (SE) | 2.9 (0.3) | 2.3 (0.3) | 7.5 (0.6) | 1.0 (0.1) | <0.001 |
| Body mass percentile†, % (SE) | 72 (2.1) | 51 (3.2) | 87 (2.0) | 86 (2.0) | <0.001 |
| Pre-bronchodilator FEV1, % predicted (SE) | 86.3 (1.5) | 86.3 (2.7) | 98.5 (2.4) | 80.7 (2.3) | <0.001 |
| FEV1 change with bronchodilator (SE) | 8.8 (1.0) | 8.4 (1.6) | 6.1 (1.3) | 9.8 (1.8) | 0.367 |
| Post-bronchodilator FEV1†, % predicted (SE) | 91.9 (1.4) | 92.1 (1.7) | 103.8 (2.1) | 85.8 (2.6) | <0.001 |
| Asthma control test™† (SE) | 20.0 (0.3) | 21.4 (0.4) | 20.9 (0.5) | 18.2 (0.6) | <0.001 |
| NAEPP severity classification (IQR) | 3 (2, 4) | 3 (2, 3) | 3 (2, 4) | 3 (2, 4) | 0.283 |
| ITG - Composite Score (IQR) | 81.3 (64.1, 91.7) | 83.3 (66.7, 93.8) | 81.3 (61.5, 91.7) | 75.0 (64.1, 85.9) | 0.140 |
| Nasal eosinophils†, % (IQR) | 51 (3, 92) | 9 (0, 59) | 56 (4, 92) | 82 (48, 95) | <0.001 |
| Nasal neutrophils, % (IQR) | 32 (4, 72) | 49 (8, 94) | 37 (1, 49) | 13 (2, 53) | 0.031 |
| Blood eosinophils, % (IQR) | 4.0 (1.9, 6.9) | 3.9 (1.8, 7.9) | 2.5 (1.3, 5.0) | 4.6 (2.4, 7.0) | 0.138 |
| Total serum IgE†, IU/mL (IQR) | 260.5 (77.8, 640.8) | 209.5 (62.5, 506.5) | 257.0 (31.0, 469.8) | 263.0 (106.5, 626.0) | 0.343 |
| Urine cotinine, ng/mL (IQR) | 0 (0, 150) | 0 (0, 120) | 0 (0, 191) | 0 (0, 164) | 0.771 |
| One or more positive skin prick tests, % | 41 | 46 | 41 | 38 | 0.701 |
| Current beta-agonist use, % | 69 | 63 | 73 | 72 | 0.512 |
| Current inhaled steroid use, % | 35 | 25 | 36 | 42 | 0.134 |
| Current leukotriene antagonist use, % | 5 | 1 | 1 | 1 | 0.808 |
Abbreviations: NAEPP = National Asthma Education and Prevention Program; ITG = Integrated Therapeutics Group’s Child Asthma Short Form; IgE = Immunoglobulin E; SE = standard error; IQR = interquartile range.
*
Significance values among the three clusters were derived using one-way analysis of variance for normally-distributed continuous variables, Kruskal-Wallis for non-parametric continuous variables, and x2 test for discrete variables. P Values <0.05 are listed in bold.
†
Variables used to derive clusters.