2.5 Treatment evaluation
All patients enrolled in the study were treated in agreement with standardized drug therapeutic protocols in accordance with the principles of treatment for SSNHL. All patients underwent audiogram tests on the first day of treatment and 1 or 2 weeks after treatment. The evaluation of treatment outcome was based on the hearing recovery criteria described in the Guidelines for the diagnosis and treatment of SSNHL (published in China at 2015) [1]:
1. Complete recovery: the hearing thresholds of impaired frequency returned to normal, or reached the level of contralateral ears or the original level.
2. Significant recovery: the hearing thresholds of impaired frequency increased ≥30 dB on average.
3. Slight recovery: the hearing thresholds of impaired frequency increased ≥15 dB and < 30 dB on average.
4. No recovery: the average hearing threshold of impaired frequency increased < 15 dB.
We evaluated the rates of hearing recovery in the study groups and a summed rate of both complete recovery, significant recovery, slight recovery was defined as the “effective” rate.
2.6 Statistical Analysis
Data analysis was performed with GraphPad Prism 8 and Microsoft Office Excel. Continuous variables were summarized using means, standard deviations, and range values when normally distributed;categorical data were summarized as number (percentage) and analyzed by the χ2 or Fisher tests when normally distributed. Spearman’s rank correlation analysis was used to determine the relation among the investigated factors and the results were presented with a confidence interval (CI) of 95%. P < 0.05 was considered statistically significant.