Hearing in individuals enrolled for drug-resistant tuberculosis treatment: a retrospective study from a South Indian city

Abstract

Purpose Some of the anti-tuberculosis (TB) drugs used for drug-resistant tuberculosis (DR-TB) are ototoxic and can result in hearing loss with extended use. Hearing loss can be present in individuals with DR-TB even before the initiation of anti-TB treatment. Not all studies investigating the adverse drug reactions of DR-TB treatment performed standard audiometric tests on their participants. Thus, the pre-treatment hearing status of individuals with DR-TB is less documented. We aimed to retrospectively profile hearing status in individuals diagnosed with DR-TB before initiation of anti-TB medication. Method Retrospective analysis of pre-treatment audiological reports from 110 individuals (81 males) aged between 18 and 82 years diagnosed with DR-TB from August 2017 to August 2018 who reported to a tertiary care hospital in Mangaluru, Karnataka, a South Indian city was done. Case history and pure tone audiometry data were available for all individuals. Descriptive statistics for each parameter were considered and the Chi-square test of independence was performed between selected variables to check for any association between variables. Results Only 29.09% (n = 32) of the individuals reported ear and hearing-related complaints. Pre-treatment for DR-TB, 88 individuals (80%) had some degree of hearing loss in at least one ear. Mild degree (60.4%) and sensorineural type (55.68%) of hearing loss were most frequently observed. Greater hearing loss was noted at high frequencies than at low frequencies. A significant association between age and prevalence of hearing loss was found [χ 2(2, N = 110)=10.28, p < .05]. There was no significant association between age and degree of hearing loss [χ 2(8, N = 87)=4.46, p > .05] as well as age and the type of hearing loss [χ 2(4, N = 87)=4.29, p > .05]. Conclusion High prevalence of hearing loss in individuals with DR-TB before initiation of anti-TB treatment was observed. However, very few individuals reported reduced hearing during case history. We emphasise performing standard audiometric tests as recommended by the World Health Organisation (WHO) to monitor the effects of ototoxicity in individuals undergoing treatment for DR-TB rather than depending on self-reported measures of change in hearing or clinician determined need for hearing tests.