Press Releases 2023

Long-term outcomes of multidrug-resistant tuberculosis: Better than expected.

A long-term study by the Research Center Borstel, Leibniz Lung Center was able to show that the therapeutic success of patients with multidrug-resistant tuberculosis is much higher than previously assumed by the World Health Organization (WHO). The findings, now published in the journal Clinical Microbiology and Infection, suggest that to meaningfully predict treatment success, the results of long-term studies should be included.

Antibiotic resistance is increasingly complicating the control of tuberculosis. In some countries of Eastern Europe, e.g. Moldova, Belarus, Ukraine or Russia, more than one third of all tuberculosis patients are infected with multidrug-resistant bacteria, for which the best drugs of standard therapy are no longer effective. While more than 85% of all tuberculosis patients can be successfully treated today, only 60% of patients with multidrug-resistant tuberculosis are, according to the World Health Organization (WHO).

"However, the World Health Organization can't actually know if patients are actually being successfully treated, because their definitions assess treatment outcome on the last day of therapy. This is roughly like telling a cancer patient on the last day of chemotherapy that he is cured," explains Professor Christoph Lange, Medical Director of the Research Center Borstel. "Like in cancer, the disease outcome of a patient can only be called cured when the disease has not returned during the years after the end of therapy" says Lange.

Until the closure of the Medical Clinic of the Research Center Borstel, Leibniz Lung Center at the end of 2021, this clinic was the largest center for the care of patients with multidrug-resistant tuberculosis in Germany and one of the largest in Western Europe. Christina Maier, a medical student at the University of Lübeck and scholarship recipient from the German Center for Infection Research (DZIF) is a PhD student in Professor Lange's research group. She has tracked down the long-term treatment outcomes of 167 cases with multidrug-resistant tuberculosis treated at Borstel between 2002 and 2020. Since more than 90% of patients came from abroad and some also traveled back to their home countries after treatment, Maier had to follow some patients beyond the borders of Germany. The results have now been published in the journal Clinical Microbiology and Infection.

Maier was able to follow up patients for an average of 4 years, and one patient could still be reached after more than 20 years. Using the current WHO definition, only 57% of patients achieved treatment success, while in fact 77% of all patients were still alive and had no recurrence of tuberculosis. When only cases for which data were available were considered, as many as 83% of patients achieved long-term cure. The data confirm the results of a recently published pilot study.

"The outcomes are so poor with the WHO definitions because patients automatically fall into the "treatment failure" category when they change therapy due to adverse events or delayed treatment response, even though most of those treated are cured" explains Maier. "Future definitions for treatment outcomes should be based on the results of long-term studies. Current definitions lead to worse outcomes than they actually are," she adds.


Maier C, Chesov D, Schaub D, Kalsdorf B, Andres S, Friesen I; Reimann M, Lange C. Long-term treatment outcomes in multidrug-resistant tuberculosis. Clin Microbiol Infect. 2023, February 24, DOI:

Otto-Knapp R, Häcker B, Krieger D, Stete K, Starzacher K, Maier C, Heyckendorf J, Avsar K, Suárez I, Rybniker J, Bauer T, Günther G, Lange C. Long-term multidrug- and rifampicin-resistant tuberculosis treatment outcome by new WHO definitions in Germany. Eur Respir J. 2022 Nov 24;60(5):2200765. doi: 10.1183/13993003.00765-2022. PMID: 36423919.


Prof. Dr. med. Dr. h.c. Christoph Lange
Medical Director, Research Center Borstel, Leibniz Lung Center
Professor of Respiratory Medicine & International Health, University of Lübeck
Parkallee 35
D-23845 Borstel, Germany
T +49 4537 188 3321/0
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