Risk Factors For Treatment-Induced Hearing Impairment: Perspective From A Resource-Poor African Setting

Abstract

Background - Treatment-induced hearing impairment can result from prolonged administration of
potentially ototoxic medications often in the pharmacotherapeutic management of chronic illnesses
such as drug-resistant tuberculosis. Whereas drug ototoxicity may be idiosyncratic, it is imperative to be
aware of its potential risk factors while treating patients. We aimed in our study to identify risks factors
for hearing impairment in patients treated for drug-resistant pulmonary tuberculosis at our Centre.

Patients and methods – This study was a 24-month prospective study of drug-resistant tuberculosis
patients treated at the pulmonology unit of Federal Medical Centre, Owerri, Nigeria. Each patient had
pure tone audiometry before commencement of treatment (baseline) and after three months of treatment
for comparison. Clinical data was obtained using pre-tested examiner-administered questionnaire.
Data collected was analyzed with SPSS version 25.0 and statistical significance set at p < 0.05.

Results - Thirty-eight (38) participants completed the study with a male-to-female (M:F) ratio of 1.53:1.
The modal age group was 41-50 years and median duration of presenting complaints 9.9 weeks. HIV seroprevalence
was 18.4% among the study participants. The baseline prevalence of hearing impairment
was 73.7% but increased to 89.5% after three months of treatment with a cumulative incidence of 15.8%
which was statistically significant (p < 0.001). The identified risk factors for hearing impairment were
age (>50 years), family history of hearing impairment, kanamycin administration and BMI <18.5kg/m2.

Conclusion – Kanamycin was associated with more severe hearing impairment than capreomycin.
Advancing age, family history of hearing impairment and BMI < 18.5kg/m2 were risk factors for
development of hearing impairment in patients treated for drug-resistant tuberculosis in our setting.