Trends of Xpert MTB/RIF in the diagnosis of Mycobacterium tuberculosis and rifampicin resistance in Southwest Nigeria: A 4-year retrospective study

Abstract

Objectives: In recent years, there has been an increased uptake of Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) for the diagnosis of tuberculosis (TB), with added benefits for detecting rifampicin-resistant TB (RR-TB). We set out to determine the trends in notification of MTB and RR-TB over 4 years in a tertiary hospital in Southwest Nigeria. Materials and Methods: This is a retrospective analysis of single early morning sputum/gastric washing sample for presumed TB in a tertiary health center between January 2016 and December 2019. Xpert MTB/RIF was used to detect (MTB) and RR-TB. Results: The mean age of the 4625 presumptive TB patients was 43.4 (18.8) years, with the majority aged 31–45 (30.6%). Males totaled 2247 (49.6%). Human immunodeficiency virus (HIV) coinfection was found in 756 (16.7%) of them. Using the Xpert MTB/RIF assay, the overall MTB notification was 12.9% (584/4526) and was associated with HIV status, P < 0.001. MTB notification trends increased from 5.6% in 2016 to 23.8% in 2019, P < 0.001. The overall yield of RR-TB was 7.5%. The proportion of RR-TB from TB cases declined from 28% in 2016 to 4.6% in 2019. Forty-two of the 44 cases of the RR-TB (42/572; 7.3%, [95% CI: 5.31, 9.75]) were new cases, with TB treatment failure and relapse cases accounting for 10.1% (2/11; 10.1%, [95% CI: 0.35, 42.5]) of all RR-TB cases (P < 0.01). RR-TB was associated with being older than 45 years (adjusted odds ratio = 2.046, [95% CI: 1.046, 4.004]). HIV infection status and gender had no effect on RR-TB status. Conclusion: This study found an increase in MTB detection with Xpert MTB/RIF utilization. Ages >45 years have 2–4-fold increased risk of developing RR-TB and should be targeted for drug resistance prevention.