The Association of Intra-Operative Steroid Administration on Hearing Threshold and Speech Perception Outcomes in Adult Cochlear Implant Recipients: A Retrospective Cohort Study

Background: Intra-operative steroid administration during cochlear implantation is intended to reduce cochlear inflammation and preserve auditory function, but clinical evidence of benefit remains inconsistent. This study evaluated the association between intra-operative steroid use and post-operative pure tone audiometry (PTA) thresholds and speech perception outcomes in adult cochlear implant recipients. Methods: A retrospective cohort study was conducted including 370 adults with complete PTA data and 332 with interpretable speech perception scores. Patients were stratified by intra-operative steroid use (PTA: n = 112; speech: n = 96) versus no steroid use (PTA: n = 258; speech: n = 236). Post-operative PTA represented unaided residual acoustic hearing, measured without the cochlear implant at 500, 1000, 2000, 4000 and 8000 Hz. Speech perception was assessed using BKB and AB tests in quiet, with the CI alone, at three months after CI activation, using the same testing approach for all patients. Between-group comparisons were performed using parametric and non-parametric tests. Analysis of covariance (ANCOVA) was used to adjust for baseline performance. Sensitivity analyses and subgroup analyses stratified by pre-operative speech scores were undertaken. Results: Residual acoustic PTA improved substantially in both groups, with no significant between-group difference (steroid: 27.1 dB vs. no-steroid: 30.4 dB; p = 0.107). ANCOVA confirmed no independent association between steroid use and PTA outcome (β = −0.14 dB, 95% CI −1.80 to +1.52; p = 0.869). In contrast, the steroid group demonstrated lower post-operative speech perception (64.5% vs. 71.3%; p = 0.048) and smaller improvement from baseline (36.6 vs. 47.1 percentage points; p = 0.004). After adjustment, steroid use was associated with an 8.4 percentage point lower speech score (95% CI 2.0 to 14.8; p = 0.010). This finding was consistent across multiple sensitivity analyses. Subgroup analyses did not show statistically significant differences in most baseline strata, although a significant association was observed in patients with higher pre-operative speech scores. Given the observational design, this association may reflect unmeasured confounding, including surgical selection factors. Conclusions: Intra-operative steroid use was not associated with improved PTA outcomes in this cohort. An observed association with lower speech perception outcomes is likely influenced by residual confounding and should be interpreted with caution. Prospective, standardised studies are required to determine the role of intra-operative steroids in cochlear implantation.