Metabolic disorders prevalence in sudden deafness

OBJECTIVES The aim of the present study was to establish the frequency of metabolic disorders among patients with sudden deafness and to compare this frequency with data from population surveys. INTRODUCTION No consensus has been reached regarding the prevalence of metabolic disorders among sudden deafness patients or their influence as associated risk factors. METHODS This cross-sectional study enrolled all sudden deafness patients treated in the Otolaryngology Department of the University of São Paulo between January 1996 and December 2006. Patients were subjected to laboratory exams including glucose and cholesterol levels, low-density lipoprotein cholesterol fraction, triglycerides, free T4 and TSH. RESULTS The sample comprised 166 patients. We observed normal glucose levels in 101 (81.5%) patients and hyperglycemia in 23 (18.5%) patients, which is significantly different (p < 0.0001) compared to the diabetes mellitus prevalence (7.6%) in the Brazilian population. Cholesterol levels were normal in 78 patients (49.7%) and abnormal in 79 (50.3%) patients, which is significantly different compared to the Brazilian population (p = 0.0093). However, no differences were observed in low-density lipoprotein cholesterol fraction (p = 0.1087) or triglyceride levels (p = 0.1474) between sudden hearing loss patients and the Brazilian population. Normal levels of thyroid hormones were observed in 116 patients (78.4%), and abnormal levels were observed in 32 (21.6%) patients. Compared with the prevalence of thyroid disorders in the general population (10%), statistical analysis revealed a significant difference (p = 0.0132) between these two groups. DISCUSSION Among sudden deafness patients, we observed frequencies of hyperglycemia and thyroid disorders that were more than twice those of the general population. CONCLUSIONS Hyperglycemia and thyroid disorders are much more frequent in patients with sudden deafness than in the general population and should be considered as important associated risk factors.