Prevalence of Pre-Existing Hearing Loss Among Patients With Drug-Resistant Tuberculosis in South Africa

Purpose Hearing loss, resulting from aminoglycoside ototoxicity, is common among patients with drug-resistant tuberculosis (DR-TB). Those with pre-existing hearing loss are at particular risk of clinically important hearing loss with aminoglycoside-containing treatment than those with normal hearing at baseline. This study aimed to identify factors associated with pre-existing hearing loss among patients being treated for DR-TB in South Africa. Method Cross-sectional analysis nested within a cluster-randomized trial data across 10 South African TB hospitals. Patients ≥ 13 years old received clinical and audiological evaluations before DR-TB treatment initiation. Results Of 936 patients, average age was 35 years. One hundred forty-two (15%) reported pre-existing auditory symptoms. Of 482 patients tested by audiometry, 290 (60%) had pre-existing hearing loss. The prevalence of pre-existing hearing loss was highest among patients ≥ 50 years (adjusted prevalence ratio [aPrR] for symptoms 5.53, 95% confidence interval (CI) [3.63, 8.42]; aPrR for audiometric hearing loss 1.63, 95% CI [1.31, 2.03] compared to age 13-18 years) and among those with a prior history of second-line TB treatment (aPrR for symptoms 1.73, 95% CI [1.66, 1.80]; PrR for audiometric hearing loss 1.33, 95% CI [1.03, 1.73]). Having HIV with cluster of differentiation 4 cell count 3 and malnutrition were risk factors but did not reach statistical significance in adjusted analyses. Conclusion Pre-existing hearing loss is common among patients presenting for DR-TB treatment in South Africa, and those older than the age of 50 years or who had prior second-line TB treatment history were at highest risk.