Extensively drug-resistant tuberculosis (TB) treatment globally has a success rate of about 44%, which is far below the World Health Organization’s (WHO) target rate of 75%, according to a study in the Journal of Infection.
Researchers conducted a systematic review and meta-analysis to estimate the proportion of patients with extensively drug-resistant tuberculosis globally who have achieved successful treatment outcomes. A search was performed in the PubMed/MEDLINE, Scopus, Web of Science, and Embase databases on June 13, 2022, with an updated search on April 3, 2023.
Eligible studies were published from 2005 onward and reported information on treatment outcomes, as defined by WHO, of pre-extensively and/or extensively drug-resistant tuberculosis (using 2006 and 2021 definitions). Observational studies and randomized controlled trials (RCTs) were considered for inclusion.
Pooled proportions were calculated for successful and unsuccessful outcomes for pre-extensively and extensively drug-resistant tuberculosis.
During this past era of treating extensively drug-resistant tuberculosis with long, ineffective, and intolerable regimens, under the 2006 definition, improvements in treatment outcomes have generally stagnated.
The analysis included 107 articles, of which 94 reported extensively drug-resistant tuberculosis outcomes. All studies were observational except for 1 RCT and were conducted in 26 countries with 10,223 participants (median, 44; range, 16-1741) who were treated for extensively drug-resistant tuberculosis.
The pooled proportion of individuals who had extensively drug-resistant tuberculosis with a successful vs unsuccessful outcome was 44.2% (95% CI, 38.3-50.3) vs 55.8% (95% CI, 49.7-61.7), respectively.
Among studies in which all successful and unsuccessful outcomes were completely stratifiable (n=48 studies, 5713 patients), the pooled proportion of cured patients was 26.9% (95% CI, 19.1-36.4) and the pooled proportion with treatment completed was 8.9% (95% CI, 6.4-12.3).
Studies that used adaptions of WHO treatment outcome definitions (n=14) had greater treatment success (56.9%; 95% CI, 36.7-74.9). Outcomes improved slightly after 2013. The highest proportions of death occurred in Africa and Southeast Asia (43.1%; 95% CI, 26.3-61.7 and 51.3%; 95% CI, 39.8-62.6, respectively).
The pooled proportion of successful outcomes in 25 studies regarding pre-extensively drug-resistant tuberculosis was 63.3% (95% CI, 43.1-72.5) compared with 36.7% (95% CI, 27.5-46.9) for unsuccessful outcomes (I2=93.5%) (n=3564 individuals).
Among several limitations, almost all studies were observational and many were retrospective. Also, the length of inclusion periods ranged from 1 to 15 years, there was a large degree of heterogeneity, and some patients had unknown outcomes without individual participant data.
“During this past era of treating extensively drug-resistant tuberculosis with long, ineffective, and intolerable regimens, under the 2006 definition, improvements in treatment outcomes have generally stagnated,” stated the researchers. “We observed a success rate of only 44.2% (with a cure rate of only 27% for patients with available data), which is similar to an estimate from 2010 and recent WHO data, but still discouragingly far away from the WHO’s goal of 75% and similar to long-term tuberculosis survival rates in the pre-antibiotic era.”
Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.