Background Drug-resistant tuberculosis (DR-TB) remains a major challenge for TB control, with treatment success rates in Loreto, Peru, consistently below national averages. Nearly half of DR-TB patients in this Amazonian region experience loss to follow-up, treatment failure, or death, underscoring the need to identify region-specific factors associated with unsuccessful outcomes.

Methods Retrospective cohort study including 417 MDR-TB cases registered in the national TB system in Loreto between 2015 and 2023. The unsuccessful treatment outcomes analyzed included loss to follow-up, mortality and therapeutic failure. Binary and multivariate logistic regression analyses were performed to identify risk factors associated with unsuccessful outcomes.

Results Of the total number of cases, 49.5% had unsuccessful outcomes: 34.1% due to treatment dropout, 3.6% treatment failure, and 11.8% mortality. In the multivariate analysis, the factors significantly associated with unsuccessful outcomes were age between 18 and 30 years (OR: 2.8; CI: 1.1-7.1), alcoholism (OR: 3.76; CI: 1.1-12.7), drug addiction (OR: 4.48; CI: 1.2-17.2) and MDR-TB (OR: 2.2; CI: 1.2-3.8).

Conclusions The identified risk factors should be the focus of priority programmatic interventions and future research aimed at optimizing regional strategies for TB control in Loreto.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol was reviewed and approved by the Research Ethics Committee of the Regional Hospital of Loreto (Approval No. ID-058-CIEI-2025). Authorization for access to and use of the Tuberculosis Management Information System (SIGTB) database was granted by the Regional Health Directorate (GERESA) of Loreto. Given the retrospective design and exclusive use of anonymized secondary data, informed consent was not required. Patient confidentiality and data security were maintained throughout the study.

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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All data underlying the findings of this study are fully available without restriction and are provided within the manuscript and its Supporting Information files