Long term audiological evaluation of beta-thalassemic patients.

Objective: The objective of this study was to identify the incidence and to monitor the progression of hearing loss in children and young adults with beta-thalassemia major.

Methods: One hundred and four (104) patients aged 6-35 years (mean 17,2 years) participated in the study. All patients were on a regular transfusion-chelation program maintaining a mean hemoglobin level of 9.5 gr/dl. Subjects were receiving desferrioxamine (DFO) chelation treatment with a mean daily dose of 50-60 mg/kg, 5-6 days a week during the first six years of the study, which was then reduced to 40-50 mg/kg for the following eight years. Patients were followed for 8-14 years.

Results: Overall, 21 out of 104 patients (20.2%) presented with high frequency sensorineural hearing loss (SNHL), either unilateral or bilateral. No ototoxic factor, other than DFO, was present in any of the patients. Patients with SNHL presented with relatively lower serum ferritin levels than those with normal hearing, however, no statistically significant difference was observed. Subjects with SNHL were submitted to DFO reduction or temporary withdrawal. Following intervention, 7 out of 21 affected patients recovered, 10 remained stable and 4 demonstrated aggravation.

Conclusion: The findings are indicative of DFO's contributing role in the development of hearing impairment. Regular audiologic evaluation is imperative in all thalassemic patients so that early changes may be recognized and treatment may be judiciously adjusted in order to prevent or reverse hearing impairment.