Effect of Comorbid Diabetes and Hypercholesterolemia on the Prognosis of Idiopathic Sudden Sensorineural Hearing Loss

Objectives: We tested the hypothesis that comorbid diseases significantly affect the prognosis of sudden sensorineural hearing loss (ISSNHL). Study Design: A retrospective cohort study. Methods: The records of patients newly diagnosed with ISSNHL and treated with steroid prednisolone in a tertiary referral center between January 2003 and December 2013 were retrospectively reviewed. Pretreatment and posttreatment hearing levels were evaluated using pure-tone average (PTA) and word recognition score (WRS). The comorbidities of diabetes, hypertension, coronary artery disease, hypercholesterolemia, cerebrovascular disease, chronic kidney disease, and anemia were identified. We examined the effects of these comorbid diseases on the prognosis of ISSNHL 2 months posttreatment. Results: Regression analyses adjusted for gender, age, pretreatment hearing, treatment delay time, and all the comorbidities showed that the probability of major improvement in the PTA was significantly higher in patients without diabetes compared to those with diabetes (univariate odds ratio [OR], 1.90; 95% confidence interval (CI), 1.25-2.90; multivariate OR, 1.69; 95% CI, 1.03-2.77). Major (>= 90%) and moderate (50%-89% improvement of the PTA, but with a remaining hearing loss of > 10 dB) improvement in the PTA was significantly higher in patients without hypercholesterolemia compared to those with hypercholesterolemia (univariate OR, 1.78; 95% CI, 1.13-2.80; multivariate OR, 1.70; 95% CI, 1.02-2.84). There was, however, no significant difference in the distribution of major (> 90%), moderate (50%-89%), and minor (< 50%) improvement in the posttreatment WRS for these comorbid diseases. Conclusions: Comorbid diabetes or hypercholesterolemia may indicate a smaller probability of major or moderate PTA improvement for patients with ISSNHL.