Research Article: Poor outcomes in recurrent tuberculosis: More than just drug resistance?

Date Published: May 6, 2019

Publisher: Public Library of Science

Author(s): Danielle B. Cohen, Geriant Davies, Wakisa Malwafu, Helen Mangochi, Elizabeth Joekes, Simon Greenwood, Liz Corbett, S. Bertel Squire, Hasnain Seyed Ehtesham.


Approximately 11% of people reported to have tuberculosis (TB) have previously received treatment. Clinical outcomes are consistently poor on retreatment regimens, however reasons for this are unclear. This study aimed to explore factors which may contribute to unsuccessful outcomes in retreatment TB.

A prospective cohort of consecutive patients starting WHO Category II retreatment regimen was recruited at a central hospital in Malawi. Participants were evaluated at baseline, after completion of the intensive phase at 2-months, and at the end of the 8-month treatment course. Patients were assessed for respiratory co-morbidity; anaemia; renal impairment; diabetes; Anti-retroviral (ART) failure; and drug toxicity. Amongst 158 patients entering TB care at the point of a recurrent episode, only 92 (58%) had a microbiologically confirmed diagnosis. The prevalence of drug resistance was low (9.6%). Of the 158 patients, 131 (83%) were HIV-positive, of whom 96 (73%) were on ART. Of 63 patients on ART >1 year, 24 (38%) had ART failure. Chronic lung disease was found in 88% on CT thorax, including scarring (80%), bronchiectasis (61%), COPD (22%), and destroyed lung (19%). Spirometry revealed restrictive deficit in 60%, and obstructive deficit in 7% of patients. Anaemia and renal impairment were common (34% and 45% respectively). Ototoxicity developed in 32%, and nephrotoxicity in 15%. 40% of patients reported peripheral neuropathy. Liver injury developed in 4%.

If outcomes are to be improved in retreatment TB, there is an urgent need to address the impact of other co-morbid medical conditions including chronic lung disease, HIV and ART failure.

Partial Text

Each year, approximately 11% of all people reported to have tuberculosis (TB) have previously received treatment, which in 2016 amounted to 0.6 million people [1]. Although it accounts for a minority of those treated for TB, retreatment TB is associated with a disproportionate burden for patients, families and health systems.

Between June 2013 and September 2014, 158 patients were enrolled (Fig 1). Baseline characteristics of the study population are shown in Table 1.

This study confirms once again that outcomes in patients receiving recurrent courses of TB treatment are poor with only 68.4% of patients successfully completing treatment. Despite no rifampicin resistance in this cohort, outcomes were no better than those reported for the treatment of MDR-TB in many other cohorts [21]. More importantly, these data also provide new insights into reasons which may explain poor outcomes in patients with retreatment tuberculosis.




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