The Prevalence of Sensorineural Hearing Loss in β-thalassaemia patient treated with Desferrioxamine

OBJECTIVE: This study aimed to evaluate the prevalence of sensorineural hearing loss (SNHL) in β-thalassaemia patients treated with Desferrioxamine (DFO) and determine the correlation of SNHL with average daily DFO dosage, serum ferritin level and Therapeutic index (T.I).

METHODS: This is a cross sectional descriptive study carried out for a period of 14 months and 54 patients were recruited. The recruited patients are transfusion dependant β- thalassaemia patient aged 3 years and above treated with DFO. An interview, clinical examination and hearing assessment, which included tympanogram, and Pure Tone Audiometry (PTA) or behaviour alaudiometry were performed. The data on age started on DFO, average daily DFO, duration of DFO intake, serum ferritin past 1 year and Therapeutic Index (T.I) were obtained from patients' case notes.

RESULTS: The prevalence of SNHL was 57.4% and majority has mild hearing loss (93.6%). Fourteen patients (25.9%) have bilateral ear involvement and as many as 17 patients (31.5%) have SNHL in either ear. A total of 23 patients (42.6%) have normal hearing level. Although the prevalence of SNHL was 57.4%, only a small percentage of the patient noticed and complained of hearing loss (11.1%). There is no association between age started on DFO, average daily DFO and duration of DFO intake with normal hearing group and those patients with SNHL. Positive correlation was seen between average daily DFO with 2000 and 4000Hz on PTA in the left ear and between serum ferritin level past 1 year with 4000 and 8000Hz in the right ear and 8000Hz in the left ear. No significant correlation was seen between T.I on PTA.

CONCLUSION: The prevalence of SNHL from hearing assessment is high in β-thalassaemia patients in this study. However, it is manifested clinically in a smaller percentage. We suggest a baseline hearing assessment should be carried on all β-thalassaemia patients prior to DFO chelation therapy.