Decentralized Diagnosis and Treatment of Drug-Resistant Tuberculosis in Machakos County, Kenya

Background: Access to drug susceptibility testing (DST) for drug-resistant tuberculosis (DR-TB) diagnosis is challenging. Between 2016-2019, in Machakos county, Kenya, Xpert MTB/RIF was available in 5 sites. Additional DST was done in the national lab. DR-TB treatment was available in 32 clinics. Methods: This is a cohort study on DR-TB diagnosis, treatment outcomes, and their predictors in Machakos county, between 2016-2019. Rifampicin-resistant TB (RR-TB) was treated with a short treatment regimen (STR). A long regimen was used for patients not eligible for the STR.Results: Of 85 DR-TB patients, 84 (99%) and 72 (73%) had Xpert MTB/RIF and phenotypic rifampicin DST results, respectively. Of 85, 36 (42%) had rifampicin-susceptible drug-resistant TB (RS/DR-TB); resistance to other first-line drugs than rifampicin) and 49 (58%) had RR-TB. Xpert MTB/RIF and phenotypic DST showed discordant results for rifampicin in 8 patients (7 with RR missed on Xpert MTB/RIF). Of 49 with RR-TB, 45 had second-line DST results. One patient had TB resistant to fluoroquinolone and second-line injectables. Of 36 RS/DR-TB patients, 33 (92%) were treated successfully. Six RR-TB patients died before starting treatment. One RR-TB patient was transferred out. Among the remaining 42 RR-TB patients, treatment success was 50% (11/22) for the STR and 80% (16/20) for the long regimen (p=0.04), with more PLHIV among patients on the STR (70% (14/22) vs 30% (6/20), p=0.03). HIV co-infection (aOR 8.5, 95%CI:1.2-59.2) but not STR use (aOR 1.5, 95%CI:0.3-8.1) predicted having a clinically unfavorable outcome (mortality or treatment failure). Seven patients (all RR-TB and HIV-positive) had severe or life-threatening adverse events, of whom 4 died. Conclusion: RR-TB treatment success was lower than the 75% World Health Organization target. HIV co-infection and adverse events contributed to unsuccessful treatment outcomes. Decentralization of rapid DST, adverse event monitoring and management, and less toxic RR-TB regimens will be key towards improving outcomes.