Outpatient treatment of drug-resistant tuberculosis in a hyperendemic setting.

Abstract

Background: The existence of multidrug-resistant tuberculosis (MDR-TB) represents a failure of effective infection control. There are over half a million new cases diagnosed annually with treatment success rates of only 57% reported in 2019. These numbers are highest in hyperendemic regions of the world, including South Africa, which has a high burden of tuberculosis and HIV co-infection. Treatment of MDR-TB is challenging and is usually managed at specialised centres. There is currently a transition into the decentralised treatment of MDR-TB for outpatients. Describing the features of DR-TB may influence improved treatment strategies for the future. Objectives: To determine the prevalence of DR-TB at a single, central outpatient site in a hyperendemic area of South Africa, and to evaluate known risk factors and their relationship with outcomes, including time between diagnosis and treatment initiation. Methods: A retrospective chart review of all new cases of DR-TB referred to a central hospital in Durban for outpatient care for the period 01/01/2017 to 31/03/2017 was conducted. Data included demographics, co-morbidities, time-to-treatment, treatment adverse effects and outcomes and were collected and collated from physical charts and the computerised registry. The data was then analysed using SPSS software. Results: The period prevalence of MDR-TB at the site was 44 cases/100 000 population. Of these cases, one hundred and eleven new cases of DR-TB were included in the analysis which comprised 57 (51.35%) males. Most patients were of African ethnicity (n = 107, 96.4%). Thirty-one (27.9%) patients did not have HIV co-infection. More than one-half of patients (n = 56, 51.5%) had a history of TB and was significantly higher in males than in females (n = 34, 59.6%) and n = 22, 40.7%) respectively; p= 0.020). Five (4.5%) patients had co-morbidities of hypertension, diabetes mellitus, or renal impairment. Most patients (n = 98, 88.3%) were treated within three months of diagnosis. The mean time-to-treatment was significantly longer in patients with extrapulmonary DR-TB (150.14 (±175.90) days compared to 53.21 (±66.01) days; p-value=0.002). Significantly more patients were treated within 6 weeks if they had a positive GeneXpert test (n = 35, 89.7% compared to n = 11, 17.5%, p=0.013). Fifty-one different treatment regimens were used, and 139 side-effects were reported, the most common being ototoxicity, hypothyroidism and peripheral neuropathy. Eighty-two (73.87%) patients completed follow-up until cure. Conclusion: The high burden of TB and HIV co-infection as well as a history of TB are associated with the elevated prevalence of MDR-TB in this setting. Side-effects are common and may impact toward poorer treatment adherence in addition to co-morbidities. Outcomes are favourable in specialised outpatient settings. A decentralised approach reduces the time-to-treatment in other studies, but large-scale implementation is recommended for further evaluation.