Serum Bilirubin Level as a Potential Marker for the Hearing Outcome in Severe-Profound Bilateral Sudden Deafness

OBJECTIVE: To investigate the association of serum bilirubin level with hearing outcomes in bilateral sudden sensorineural hearing loss (BSSHL) patients. PARTICIPANTS: One hundred thirteen in-patient BSSHL patients were consecutively enrolled between July 2008 and December 2015 in a tertiary center. MAIN OUTCOME MEASURES: Multivariable linear regression, generalized estimating equations (GEE), and stratified analyses were applied to examine the association between serum bilirubin level and hearing outcome measures such as final hearing threshold and absolute and relative hearing gains in BSSHL. RESULTS: After full adjustment for potential confounders, total bilirubin levels (TBIL) were observed to be positively and independently associated with hearing outcomes as measured by final hearing (β [95% confidence interval {CI}]: −1.5 [−2.7, −0.2] dB HL per 1 μmol/L increase in TBIL) and absolute and relative hearing gains (β [95% CI]: 1.4 [0.2, 2.7] dB and 1.6 [0.2, 3.1] dB, respectively) in the severe to profound hearing loss subpopulation. CONCLUSIONS: Higher TBIL levels, within the normal or mildly elevated ranges, were independently and significantly associated with better hearing outcome in BSSHL patients with severe to profound hearing loss. Given bilirubin elevation treatments exist, our finding suggests a novel pharmacological strategy for this specific subpopulation.