Table 2.
Clinical-Failure Rates for the Index Episode of Acute Otitis Media at or before the End-of-Treatment Visit, According to Selected Characteristics at Entry.*
| Characteristic | 10-Day Group (N = 257) | 5-Day Group (N = 258) | All Children (N = 515) | Odds Ratio (95% CI)† | P Value |
|---|---|---|---|---|---|
| no. of children with clinical failure/total no. (%) | |||||
| All children | 39/238 (16) | 77/229 (34) | 116/467 (25) | NA | — |
|
| |||||
| Age at entry | 0.94 | ||||
| 12–23 mo | 15/116 (13) | 41/111 (37) | 56/227 (25) | Reference | |
| 6–11 mo | 24/122 (20) | 36/118 (31) | 60/240 (25) | 1.0 (0.7–1.6) | |
|
| |||||
| Exposure to other children | 0.02 | ||||
| No | 13/101 (13) | 24/96 (25) | 37/197 (19) | Reference | |
| Yes | 26/137 (19) | 53/133 (40) | 79/270 (29) | 1.7 (1.1–2.7) | |
|
| |||||
| AOM-SOS score at entry | 0.19 | ||||
| ≤8 | 20/108 (19) | 43/117 (37) | 63/225 (28) | Reference | |
| >8 | 19/130 (15) | 34/112 (30) | 53/242 (22) | 0.8 (0.5–1.2) | |
|
| |||||
| Ears affected by otitis media | <0.001 | ||||
| One | 10/124 (8) | 26/113 (23) | 36/237 (15) | Reference | |
| Both | 29/114 (25) | 51/116 (44) | 80/230 (35) | 2.9 (1.9–4.7) | |
|
| |||||
| Degree of tympanic-membrane bulging in worse ear | 0.12 | ||||
| Slight or moderate | 23/158 (15) | 49/157 (31) | 72/315 (23) | Reference | |
| Marked | 16/80 (20) | 28/72 (39) | 44/152 (29) | 1.4 (0.9–2.2) | |
|
| |||||
| Estimated severity of illness on the basis of pain and fever history only | 0.38 | ||||
| Probably nonsevere | 21/104 (20) | 28/107 (26) | 49/211 (23) | Reference | |
| Probably severe | 18/134 (13) | 49/122 (40) | 67/256 (26) | 1.2 (0.8–1.9) | |
|
| |||||
| No. of significantly unfavorable characteristics | <0.001‡ | ||||
| 0 | 4/52 (8) | 12/55 (22) | 16/107 (15) | Reference | |
| 1 | 15/121 (12) | 26/99 (26) | 41/220 (19) | 1.4 (0.7–2.6) | |
| 2 | 20/65 (31) | 39/75 (52) | 59/140 (42) | 4.3 (2.3–8.2) | |
Data were not available for some children because of missed visits. NA denotes not applicable.
The odds ratio (with 95% confidence interval [CI]) for clinical failure was calculated for the comparison of the favorable characteristic category (reference) versus the unfavorable characteristic category, with study groups combined. The category that was considered to be clinically favorable on the basis of clinical experience, earlier studies,4,13 or both is listed first, and the unfavorable characteristic second. The odds ratios and P values were adjusted for treatment group; in the case of the two characteristics showing significant differences (i.e., exposure to other children and one versus both ears affected by acute otitis media), the odds ratios and P values were also adjusted for the other such characteristic. Of 14 tests for significant interactions between treatment and the individual characteristics, all were nonsignificant except in the case of the estimated severity of acute otitis media at entry. In the 10-day group, the clinical-failure rate was higher among children with probably nonsevere illness than among those with probably severe illness, and in the 5-day group, the rate was higher among children with probably severe illness than among those with probably nonsevere illness (P = 0.01 for interaction).
The P value was derived from a test for linear trend from zero to two.