Table 3.
Comparison between the NAC and non-NAC groups.
| Characteristics | NAC, N = 94 (%) | Non-NAC, N = 125 (%) | P value |
|---|---|---|---|
| Gender | .171 | ||
| Male | 50 (53.1) | 54 (43.2) | |
| Female | 44 (46.9) | 71 (56.8) | |
| Side | .133 | ||
| Left | 53 (56.4) | 57 (45.6) | |
| Right | 41 (43.6) | 68 (54.4) | |
| Age, yr | 48.1 ± 17.9 | 47.4 ± 15.5 | .745 |
| <18 yr | 7 (7.6) | 5 (4.0) | .233 |
| 18–65 yr | 67 (71.2) | 101 (80.8) | |
| >65 yr | 20 (21.2) | 19 (15.2) | |
| Duration of onset of hearing loss, d | 2.2 ± 0.8 | 2.4 ± 0.6 | .145 |
| Underlying diseases | |||
| Hypertension | .387 | ||
| Yes | 15 (15.9) | 26 (20.8) | |
| No | 79 (84.1) | 99 (79.2) | |
| Coronary artery disease | .589 | ||
| Yes | 7 (7.4) | 7 (5.6) | |
| No | 87 (92.6) | 118 (94.4) | |
| CRP, mg/L ± SD | 1.6 ± 1.9 | 1.2 ± 1.6 | .378 |
| Unaffected ears | |||
| 250 Hz, dB ± SD | 14.2 ± 9.4 | 18.5 ± 16.4 | .055 |
| 500 Hz, dB ± SD | 15.3 ± 7.6 | 18.2 ± 13.4 | .519 |
| 1k Hz, dB ± SD | 17.7 ± 8.8 | 21.4 ± 14.1 | .264 |
| 2k Hz, dB ± SD | 19.0 ± 12.6 | 22.3 ± 17.4 | .226 |
| 4k Hz, dB ± SD | 20.1 ± 18.7 | 25.3 ± 24.7 | .230 |
| 8k Hz, dB ± SD | 22.9 ± 21.5 | 26.7 ± 27.1 | .324 |
| Mean hearing level, dB ± SD | 18.2 ± 11.2 | 22.0 ± 17.7 | .432 |
| Tympanometry type A | 94 (100.0) | 125 (100.0) | 1.000 |
| Tympanometry type B | 0 (0.0) | 0 (0.0) | 1.000 |
| Tympanometry type C | 0 (0.0) | 0 (0.0) | 1.000 |
| SRT, dB ± SD | 14.8 ± 6.2 | 18.8 ± 13.6 | .202 |
| SDS, % ± SD | 97.8 ± 6.2 | 96.3 ± 11.4 | .334 |
| Pretreatment of affected ears | |||
| 250 Hz, dB ± SD | 69.7 ± 24.6 | 71.8 ± 22.2 | .768 |
| 500 Hz, dB ± SD | 74.8 ± 22.7 | 78.6 ± 20.1 | .338 |
| 1k Hz, dB ± SD | 77.6 ± 20.6 | 82.3 ± 20.4 | .093 |
| 2k Hz, dB ± SD | 74.6 ± 22.1 | 76.8 ± 24.4 | .514 |
| 4k Hz, dB ± SD | 79.1 ± 21.8 | 80.1 ± 25.3 | .452 |
| 8k Hz, dB ± SD | 81.7 ± 18.6 | 79.3 ± 25.2 | .977 |
| Mean hearing level, dB ± SD | 76.3 ± 18.4 | 78.1 ± 20.0 | .428 |
| Tympanometry type A | 92 (97.8) | 122 (97.6) | 1.000 |
| Tympanometry type B | 2 (2.2) | 3 (2.4) | 1.000 |
| Tympanometry type C | 0 (0.0) | 0 (0.0) | 1.000 |
| SRT, dB ± SD | 74.5 ± 23.4 | 72.9 ± 25.6 | .679 |
| SDS, % ± SD | 44.4 ± 21.3 | 44.7 ± 18.7 | .926 |
| Posttreatment PTA of affected ears | |||
| 250 Hz, dB ± SD | 35.3 ± 21.7 | 40.3 ± 26.5 | .389 |
| 500 Hz, dB ± SD | 37.6 ± 20.0 | 45.7 ± 27.9 | .063 |
| 1k Hz, dB ± SD | 48.2 ± 20.4 | 55.6 ± 29.7 | .075 |
| 2k Hz, dB ± SD | 51.2 ± 23.6 | 56.4 ± 28.7 | .165 |
| 4k Hz, dB ± SD | 53.9 ± 23.9 | 58.0 ± 32.7 | .093 |
| 8k Hz, dB ± SD | 54.2 ± 24.4 | 60.9 ± 34.1 | .46* |
| Mean hearing level, dB ± SD | 46.7 ± 16.3 | 52.8 ± 26.9 | .073 |
| Tympanometry type A | 94 (100.0) | 125 (100.0) | 1.000 |
| Tympanometry type B | 0 (0.0) | 0 (0.0) | 1.000 |
| Tympanometry type C | 0 (0.0) | 0 (0.0) | 1.000 |
| SRT, dB ± SD | 48.2 ± 22.7 | 54.0 ± 31.2 | 0.206 |
| SDS, % ± SD | 70.0 ± 27.0 | 68.0 ± 29.0 | .732 |
| Mean hearing level gain, dB ± SD | 29.5 ± 21.8 | 25.3 ± 22.1 | .086 |
| SRT gain, dB ± SD | 26.2 ± 34.4 | 18.8 ± 32.4 | .090 |
| SDS gain, % ± SD | 25.5 ± 30.4 | 23.2 ± 30.4 | .563 |
CRP = C-reactive protein, mean hearing level = average pure tone audiometry (PTA) at 500, 1k, 2k, and 4k Hz, N = numbers, NAC = N-acetylcysteine, SD = standard deviation, SDS = speech discrimination score, SRT = speech reception threshold.
*
P < .05.