Hypercholesterolemia is correlated with an increased risk of idiopathic sudden sensorineural hearing loss: A historical prospective cohort study

OBJECTIVE:: Despite the many studies on the associated risk of cardiovascular and cerebrovascular events in patients with hypercholesterolemia (HCh), an association between HCh and the development of idiopathic sudden sensorineural hearing loss (ISSNHL) has been examined in only a few case-control studies. We tested the hypothesis that HCh is a risk factor for developing ISSNHL. DESIGN:: Using the Taiwan Longitudinal Health Insurance Database, we conducted a historical prospective cohort study to compare patients diagnosed with HCh from January 1, 2001, through to December 31, 2006 (N = 73,957) with age-matched controls (N = 73,957). We followed each patient until the end of 2009 and evaluated the incidence of ISSNHL for a minimum of 3 years after the initial HCh diagnosis. RESULTS:: The incidence of ISSNHL was 1.62 times higher in the HCh cohort than in the non-HCh cohort (10.67 versus 6.61 per 10,000 person-years). Using Cox proportional hazard regressions, the adjusted hazard ratio was 1.60 (95% confidence interval [CI] = 1.39-1.85). An increased risk of developing ISSNHL, with adjusted hazard ratios of 1.48 (95% CI = 1.08-2.04) and 1.69 (95% CI = 1.18-2.43), was observed in HCh patients with newly diagnosed comorbidities of stroke or stroke combined with coronary artery diseases, which are both expected to reflect the severity of HCh. CONCLUSIONS:: A diagnosis of HCh may indicate an independent risk for ISSNHL. This finding suggests that an underlying vascular mechanism contributes to the development of ISSNHL. We suggest that physicians counsel patients with HCh to seek medical attention if they have hearing impairments, because they may also have an increased risk of developing ISSNHL.