The correlation between lipoprotein ratios and hearing outcome in idiopathic sudden sensorineural hearing loss patients

ObjectiveRecent reports have identified hypercholesterolaemia as a significant risk factor for idiopathic sudden sensorineural hearing loss (ISSNHL). Therefore, we investigated whether lipid profiles and lipoprotein ratios are correlated with the prognosis of hearing recovery in ISSNHL patients. DesignA retrospective cohort study. Main outcome measuresPatients with ISSNHL were classified into four groups (complete, partial, slight and no recovery) according to their degree of hearing recovery using Siegel's criteria and the Sudden Deafness Research Group (SDRG) criteria developed by the Japanese Ministry of Welfare. All patients' lipid profiles were analysed, including total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol and triglycerides. We calculated the ratios of TC/HDL-C and LDL-C/HDL-C and used statistical methods to evaluate correlations between lipid profiles and lipoprotein ratios and ISSNHL prognosis. ResultsHearing recovery was observed in 103 (62.0%) of 166 cases using Siegel's criteria and in 114 (68.7%) of 166 cases using SDRG's criteria. Among the three recovery groups (i.e. excluding the no recovery group), the ratio of LDL-C/HDL-C was found to be associated with recovery outcome by showing the ratio on an upward trend from complete recovery to slight recovery group, and the difference is statistically significant (P=0.016 by Siegel's criteria, P=0.041 by SDRG's criteria). Multiple linear regression analysis further revealed a significantly higher LDL-C/HDL-C ratio in slight hearing recovery group compared with complete recovery group (P=0.007 by Siegel's criteria, P=0.031 by SDRG's criteria). ConclusionWe suggested that lipoprotein ratio of LDL-C/HDL-C may be a prognostic factor for hearing recovery in ISSNHL patients. Further studies should be conducted to determine whether hearing outcomes in ISSNHL can be improved by changing patients' lipid profiles via antilipidemic treatment.