Table 2. Characteristics of Study Participants.
| All Randomized Participants (N = 607) |
Participants With at Least 1 Treated RTI (n = 443) |
Participants With No RTI (n = 164) |
Participants With at Least 1 Treated RTI | ||
|---|---|---|---|---|---|
| Azithromycin (n = 223) |
Placebo (n = 220) |
||||
| Exposures, No. (%) | |||||
| Day-care attendance | 307 (50.6) | 220 (49.7) | 87 (53.1) | 123 (55.2) | 97 (44.1) |
| Tobacco smoke exposure, No./total (%) | 240/601 (39.9) | 164/439 (37.4) | 76/162 (46.9) | 89/221 (40.3) | 75/218 (34.4) |
| Pet in home | 280 (46.1) | 228 (51.5) | 52 (31.7) | 117 (52.5) | 111 (50.5) |
| Feature of Previous Wheezing | |||||
| No. of wheezing episodes in the past year, mean (SD) |
4.45 (3.15) | 4.45 (3.14) | 4.45 (3.19) | 4.49 (3.41) | 4.41 (2.86) |
| No. of urgent and/or ED visits in the past year, mean (SD) |
2.48 (1.64) | 2.53 (1.71) | 2.34 (1.41) | 2.52 (1.72) | 2.54 (1.71) |
| Hospitalized in the past year, No. (%) | 87 (14.3) | 58 (13.1) | 29 (17.7) | 34 (15.2) | 24 (10.9) |
| No. of hospitalizations in the past year, median (IQR) |
0 (0-1) | 0 (0-1) | 0 (0-1) | 0 (0-1) | 0 (0-1) |
| At least 1 course of OCS in past year, No. (%) | 361 (59.5) | 276 (62.3) | 85 (51.8) | 143 (64.1) | 133 (60.5) |
| No. of OCS courses in the past year, median (range) |
1 (0-4) | 1 (0-4) | 1 (0-4) | 1 (0-4) | 1 (0-4) |
| ICS use in past year, No./total (%) | 150/605 (24.8) | 126/441 (28.6) | 24/164 (14.6) | 70/223 (31.3) | 56/218 (25.7) |
| Montelukast use in the past year, No. (%) | 54 (8.9) | 48 (10.8) | 6 (3.7) | 25 (11.2) | 23 (10.5) |
| Symptom Burden During 14-d Run-in Period | |||||
| No. of days in run-in period, median (IQR) |
15 (14-19) | 15 (14-19) | 15 (14-19) | 15 (14-19) | 14 (14-19) |
| Percentage of asthma control days, mean (SD)a |
77.4 (24.1) | 76.6 (23.6) | 79.6 (25.3) | 76.3 (24.5) | 77.0 (22.6) |
| No. of asthma control days per week, mean (SD)a |
5.4 (1.7) | 5.4 (1.7) | 5.6 (1.8) | 5.3 (1.7) | 5.4 (1.6) |
| Percentage of nights with albuterol use, median (range) |
0 (0-43) | 0 (0-43) | 0 (0-36) | 0 (0-24) | 0 (0-43) |
| Percentage of days with albuterol use, median (range) |
0 (0-57) | 0 (0-57) | 0 (0-59) | 0 (0-57) | 0 (0-54) |
| Atopic Features | |||||
| Eczema, No./total (%) | 328/592 (55.4) | 242/430 (56.3) | 86/162 (53.1) | 112/215 (52.1) | 130/215 (60.5) |
| Allergic rhinitis, No./total (%) | 128/581 (22.0) | 100/420 (23.8) | 28/161 (17.4) | 52/211 (24.6) | 48/209 (23.0) |
| Parentalasthma, No./total(%) | 314/587 (53.5) | 222/428 (51.9) | 92/159 (57.9) | 114/213 (53.5) | 108/215 (50.2) |
| Physician-diagnosed asthma, No. (%) | 345 (56.8) | 248 (56.0) | 97 (59.2) | 127 (57.0) | 121 (55.0) |
| Positive modified API, No. (%)b | 284 (46.8) | 208 (47.0) | 76 (46.3) | 104 (46.6) | 104 (47.3) |
| Allergy | |||||
| Sensitivity to any allergen, No./total (%) |
314/596 (52.7) | 230/436 (52.8) | 84/160 (52.2) | 112/219 (51.1) | 118/217 (54.4) |
| No. of allergens (of 16), median (IQR) |
1 (0-3) | 1 (0-3) | 1 (0-3) | 1 (0-3) | 1 (0-3) |
| Sensitivity to ≥1 aeroallergen, No./total (%) |
233/596 (39.1) | 169/436 (38.8) | 64/160 (40.0) | 85/219 (38.8) | 84/217 (38.7) |
| No. of aeroallergens (of 13), median (IQR) |
0 (0-2) | 0 (0-2) | 0 (0-2) | 0 (0-2) | 0 (0-2) |
| Sensitivity to ≥1 food allergen, No./total (%) |
241/596 (40.4) | 179/436 (41.1) | 62/160 (38.8) | 82/219 (37.4) | 97/217 (44.7) |
| Immunoglobulin E, μg/L, median (IQR) | 122.6 (35-408.7) n = 550 |
117.1 (34.8-421.1) n = 400 |
130 (43.7-382.8) n = 150 |
132 (34.8-430.1) n = 201 |
102.5 (31-403) n = 199 |
| Peripheral blood eosinophils, median (IQR), % |
3 (2-5.6) n = 568 |
3 (2-5.3) n = 411 |
3 (2-5.8) n = 157 |
3 (2- 6) n = 205 |
3 (2-5) n = 206 |
| Eosinophils ≥4%, No./total (%) | 234/568 (41.2) | 166/411 (40.4) | 68/157 (43.3) | 85/205 (41.5) | 81/206 (39.3) |
| Study Duration When Enrolled, No. (%) | |||||
| 52 wk | 315 (51.9) | 238 (53.7) | 77 (46.9) | 117 (52.5) | 121 (55.0) |
| 78 wk | 292 (48.1) | 205 (46.3) | 87 (53.1) | 105 (47.5) | 99 (45.0) |
Abbreviations: API, asthma predictive index; ED, emergency department; ICS, inhaled corticosteroids; IQR, interquartile range; OCS, oral corticosteroids; RTI, respiratory tract illness.
a
An asthma control day was a day without asthma-related symptoms, medication use, or health care utilization.
b
A participant was classified as having a positive modified API if the individual had experienced at least 4 wheezing episodes in the past year and had1 major criterion (physician-diagnosed atopic dermatitis, parental history of asthma, or allergic sensitization to ≥1 aeroallergen) or 2 minor criteria (wheezing unrelated to colds, blood eosinophils ≥4%, or allergic sensitization to milk, eggs, or peanuts).12