Treatment outcomes of extensively drug-resistant tuberculosis in Europe: a retrospective cohort study.

Background
In 2021, World Health Organization revised of definition of extensive drug-resistant tuberculosis. We aimed to determine treatment outcomes of individuals affected by extensively drug-resistant tuberculosis in Europe.Methods
This observational, retrospective cohort study included patients diagnosed with extensively drug-resistant tuberculosis in the World Health Organization European Region from 2017 to 2023. Participating centres collected consecutive, detailed individual data for extensively drug-resistant tuberculosis patients. Data were analysed with meta- and regression methods, accounting for between-country heterogeneity.Findings
Among 11,003 patients with multidrug-resistant/rifampicin-resistant tuberculosis, 188 (1·7%) from 16 countries had extensively drug-resistant tuberculosis. Of these, 48·4% harboured strains with resistance to bedaquiline (n = 91/188), 34·0% to linezolid (n = 64/188), and 17·6% to both (n = 33/188). The individual composition of anti-tuberculosis regimens was highly variable, with 151 different drug combinations. Among the 156/188 (83·0%) patients with available treatment outcomes, the pooled percentage of successful outcomes was 40·2% (95% confidence interval [95% CI] 28·4%-53·2%). In patients with unsuccessful treatment outcomes (101/156), most experienced treatment failure (n = 57/156 [pooled proportion 37·1%], 95% CI: 26·1%-49·7%) or death (n = 30/156 [pooled proportion 21·3%], 95% CI: 15·7%-28·2%). After adjustment for disease severity, each additional likely effective drug decreased the odds of unsuccessful outcomes (adjusted odds ratio: 0·65, 95% CI: 0·45-0·96) (p = 0·026), whereas being treated in an upper-middle-income country increased the odds of unsuccessful outcomes compared with being treated in a high-income country (adjusted odds ratio: 13·7, 95% CI: 3·7-50·2) (p < 0·001). Compared with other levels of drug resistance, treatment outcomes were significantly worse for extensively drug-resistant tuberculosis.Interpretation
Only four out of ten patients affected by extensively drug-resistant tuberculosis achieved successful treatment outcomes. These findings highlight the need for adequate, individualised treatment regimens and optimised drug susceptibility testing.Funding
None.