Table 3.
Characteristics of the Selected Participants Who Had Severe, Persistent, Intermittent, and Remitting Asthma
| Late Adolescence: Ages 17–19 yr |
Early Adulthood: Ages 21–23 yr |
Stayed Severe: Ages 21–23 yr* |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Remitting | Intermittent | Persistent | Severe | P Value | Remitting | Intermittent | Persistent | Severe | P Value | Severe | P Value | |
| Participants | 24 (4) | 326 (48) | 251 (37) | 81 (12) | — | 35 (5) | 319 (47) | 197 (29) | 131 (19) | — | 42 (6) | — |
| Baseline characteristics | ||||||||||||
| Age, yr | 18.2 (0.3) | 18.3 (0.3) | 18.3 (0.4) | 18.3 (0.4) | 0.376 | 22.3 (0.3) | 22.4 (0.3) | 22.4 (0.4) | 22.4 (0.4) | 0.552 | 22.5 (0.4) | 0.180 |
| Sex, M | 54 | 61 | 57 | 64 | 0.546 | 60 | 61 | 50 | 72 | 0.002 | 79 | 0.011 |
| Ethnicity | ||||||||||||
| White | 54 | 69 | 67 | 70 | 0.700 | 69 | 63 | 70 | 75 | 0.242 | 71 | 0.822 |
| Black | 25 | 15 | 16 | 12 | 0.700 | 14 | 18 | 12 | 15 | 0.242 | 17 | 0.822 |
| Hispanic | 4 | 10 | 10 | 9 | 0.700 | 6 | 11 | 10 | 5 | 0.242 | 5 | 0.822 |
| Other | 17 | 7 | 8 | 9 | 0.700 | 11 | 8 | 9 | 6 | 0.242 | 7 | 0.822 |
| BMI percentile | 0.71 (0.29) | 0.69 (0.26) | 0.66 (0.27) | 0.69 (0.28) | 0.309 | 0.74 (0.26) | 0.73 (0.28) | 0.64 (0.34) | 0.67 (0.29) | 0.401 | 0.81 (0.20) | 0.133 |
| Duration of asthma, yr | 5.07 (2.43) | 4.46 (2.73) | 4.80 (2.45) | 5.07 (2.76) | 0.106 | 5.79 (2.25) | 4.38 (2.69) | 4.71 (2.45) | 5.06 (2.74) | 0.003 | 5.42 (2.64) | 0.051 |
| Age at symptom onset, yr | 2.64 (2.72) | 3.39 (2.72) | 3.14 (2.20) | 2.60 (2.38) | 0.023 | 1.89 (1.93) | 3.48 (2.71) | 3.05 (2.33) | 2.98 (2.28) | 0.002 | 2.06 (1.82) | 0.002 |
| Age at M.D. diagnosis, yr | 3.37 (2.96) | 4.23 (2.76) | 3.92 (2.35) | 3.40 (2.32) | 0.041 | 2.86 (2.30) | 4.34 (2.78) | 3.84 (2.34) | 3.68 (2.35) | 0.004 | 2.64 (1.72) | 0.093 |
| At least one positive SPT | 83 | 85 | 93 | 94 | 0.014 | 86 | 87 | 93 | 88 | 0.162 | 91 | 1.000 |
| Sensitized and exposed† | 58 | 69 | 79 | 83 | 0.003 | 71 | 72 | 77 | 76 | 0.614 | 74 | 0.829 |
| Eczema | 25 | 29 | 32 | 22 | 0.386 | 23 | 27 | 34 | 27 | 0.279 | 24 | 0.454 |
| Hay fever | 42 | 53 | 56 | 47 | 0.304 | 54 | 54 | 56 | 47 | 0.474 | 33 | 0.009 |
| Food allergy | 13 | 18 | 19 | 17 | 0.894 | 14 | 16 | 22 | 18 | 0.293 | 17 | 0.812 |
| Parental asthma | 46 | 40 | 45 | 48 | 0.416 | 46 | 40 | 49 | 43 | 0.227 | 50 | 0.352 |
| Treatment group in CAMP‡ | ||||||||||||
| Budesonide | 38 | 30 | 29 | 30 | 0.873 | 40 | 30 | 29 | 29 | 0.517 | 38 | 0.248 |
| Nedocromil | 17 | 29 | 32 | 30 | 0.873 | 37 | 30 | 30 | 28 | 0.517 | 19 | 0.248 |
| Placebo | 46 | 41 | 39 | 41 | 0.873 | 23 | 41 | 41 | 44 | 0.517 | 43 | 0.248 |
| Lung function | ||||||||||||
| Pre-BD FEV1% predicted | 103.7 (13.7) | 101.9 (11.2) | 95.6 (12.9) | 88.2 (15.5) | <0.0001 | 98.9 (11.7) | 99.1 (11.0) | 94.5 (14.8) | 86.7 (12.8) | <0.0001 | 81.7 (14.7) | <0.0001 |
| Post-BD FEV1% predicted | 107.1 (13.3) | 107.5 (10.6) | 103.5 (11.7) | 99.1 (14.0) | <0.0001 | 103.7 (11.3) | 104.0 (10.9) | 101.2 (13.3) | 94.6 (12.9) | <0.0001 | 90.2 (15.7) | 0.010 |
| Pre-BD FVC% predicted | 106.5 (13.6) | 109.3 (11.6) | 110.0 (12.0) | 113.6 (13.8) | 0.063 | 104.6 (11.3) | 107.6 (11.4) | 109.3 (12.2) | 110.8 (13.2) | 0.009 | 111.9 (14.2) | 0.053 |
| Post-BD FVC% predicted | 106.0 (13.0) | 109.6 (11.4) | 111.1 (11.8) | 115.0 (13.7) | 0.005 | 104.9 (11.4) | 107.7 (11.2) | 109.9 (12.0) | 111.7 (13.0) | 0.001 | 113.1 (14.3) | 0.015 |
| Pre-BD FEV1/FVC ratio | 85.6 (7.2) | 81.6 (6.6) | 76.3 (9.0) | 67.8 (10.1) | <0.0001 | 81.9 (6.4) | 80.0 (5.9) | 75.0 (9.3) | 67.9 (8.2) | <0.0001 | 62.9 (6.6) | <0.0001 |
| Post-BD FEV1/FVC ratio | 88.8 (5.7) | 85.9 (6.0) | 81.9 (7.9) | 75.4 (8.5) | <0.0001 | 85.5 (5.5) | 83.8 (5.2) | 79.9 (8.3) | 73.4 (7.8) | <0.0001 | 68.7 (6.8) | <0.0001 |
| Bronchodilator rev., % | 3.45 (2.61) | 5.75 (4.33) | 8.84 (7.44) | 13.60 (10.79) | <0.0001 | 5.00 (3.46) | 5.16 (3.88) | 7.76 (7.65) | 9.38 (6.70) | <0.0001 | 10.65 (6.85) | <0.0001 |
| Methacholine FEV1 PC20§‖ | 1.14 (0.61) | 0.81 (0.70) | 0.43 (0.73) | 0.39 (0.75) | <0.0001 | 1.33 (0.43) | 0.91 (0.68) | 0.61 (0.69) | 0.73 (0.72) | 0.002 | 0.31 (0.76) | 0.042 |
| Asthma risk | ||||||||||||
| Prednisone courses/yr | — | — | 0.30 (0.65) | 0.27 (0.84) | 0.096 | — | — | 0.14 (0.44) | 0.33 (0.79) | 0.033 | 0.31 (0.72) | 0.001 |
| ED visits/yr | — | — | 0.10 (0.51) | 0.25 (0.51) | 0.0002 | — | — | 0.13 (0.53) | 0.44 (0.83) | <0.0001 | 0.50 (1.15) | <0.0001 |
| Hospitalizations/yr | — | — | 0.01 (0.09) | 0.00 (0.00) | 0.421 | — | — | 0.01 (0.07) | 0.02 (0.12) | 0.343 | 0.05 (0.22) | <0.0001 |
| Biomarkers | ||||||||||||
| Serum IgE, ng/ml‖ | 282 (2.9) | 277 (4.2) | 541 (4.2) | 650 (3.7) | <0.0001 | 176 (4.6) | 393 (4.5) | 516 (3.0) | 338 (5.6) | 0.370 | 498 (10.1) | 0.592 |
| Eosinophil count, cells/μl‖ | 187 (1.6) | 172 (2.8) | 212 (2.9) | 164 (3.3) | 0.167 | 70 (5.8) | 139 (4.5) | 231 (3.4) | 221 (1.7) | 0.013 | 314 (2.4) | 0.362 |
| Medications | ||||||||||||
| No medication | 100 | 64 | 2 | 54 | <0.0001 | 100 | 61 | 3 | 50 | <0.0001 | 43 | 0.863 |
| Rescue medications only | 0 | 36 | 2 | 21 | <0.0001 | 0 | 39 | 2 | 31 | <0.0001 | 36 | 0.085 |
| Any daily controller therapy | — | — | 97 | 25 | <0.0001 | — | — | 95 | 19 | <0.0001 | 21 | 0.157 |
| ICS monotherapy | — | — | 13 | 0 | <0.0001 | — | — | 15 | 0 | <0.0001 | 0 | 0.248 |
| ICS + LABA | — | — | 10 | 0 | 0.001 | — | — | 24 | 2 | <0.0001 | 0 | 0.064 |
| ICS daily dose¶ | — | — | 289 (223) | 625 (214) | <0.0001 | — | — | 301 (223) | 618 (218) | <0.0001 | 642 (226) | 0.0007 |
Definition of abbreviations: BD = bronchodilator; BMI = body mass index; CAMP = Childhood Asthma Management Program; ED = emergency department; FDR = false discovery rate; ICS = inhaled corticosteroid; LABA = long-acting β-agonist; M.D. = Doctor of Medicine; PC20 = provocative concentration resulting in a 20% fall in the FEV1; rev. = reversibility; SPT = skin prick test.
Data are presented as a percentage or as the mean (SD) unless otherwise indicated. Chi-square and Fisher exact tests were used for categorical variables. Kruskal-Wallis tests were used for continuous variables. Bold P values represent significance as determined by using a Benjamini-Hochberg FDR adjustment calculated separately for the “Late Adolescence,” “Early Adulthood,” and “Stayed Severe” columns; the thresholds for significance were <0.0228, <0.0131, and <0.0153, respectively.
The “Stayed Severe” column refers to patients who had a persistence of severe asthma from late adolescence to early adulthood.
“Sensitized and exposed” refers to indoor allergens. The criteria for significant allergen exposure are as follows: cat allergen concentration >8,000 ng/g or cat allowed inside the home; dog allergen concentration >10,000 ng/g or dog allowed inside the home; mite allergen concentration >2,000 ng/g; cockroach allergen concentration >2 U/g or cockroaches in the home; and >25,000 mold colonies or mold on any surface of the home.
Refers to original treatment group assignment from the Childhood Asthma Management Program Research Group (see Reference 15).
PC20 represents the geometric mean of the concentration of methacholine needed to produce a 20% fall in the FEV1 from baseline.
Values in table represent geometric mean (SD).
Fluticasone equivalent of ICS total dose in micrograms.