Trends in Tuberculosis Incidence and Treatment Outcomes in Kazakhstan: A Decade of Observational Data

Background: Tuberculosis (TB) remains a major public health concern globally, despite sustained declines in incidence in many countries. Kazakhstan has implemented long-term national TB control strategies; however, comprehensive nationwide analyses integrating temporal trends, demographic patterns, and treatment outcomes over the past decade remain limited. Methods: A nationwide retrospective registry-based analysis of programmatic TB treatment episodes was conducted using anonymized data from the national tuberculosis registry of the Ministry of Health of Kazakhstan. All registered TB cases from 1 January 2014 to 31 December 2023 were included. Treatment outcome was analyzed as the final end-of-episode programmatic status (favorable vs. unfavorable). Because the anonymized extract did not contain complete patient-level dates required to derive person-time (treatment initiation and event dates), time-to-event models were not applied; instead, factors associated with unfavorable end-of-treatment outcomes were assessed using multivariable logistic regression and reported as adjusted odds ratios (aORs) with 95% CIs. Unfavorable treatment outcomes were defined as death, treatment failure, loss to follow-up, and not evaluated or not recorded outcome, according to the national TB program outcome definitions. Results: A total of 93,985 TB cases were analyzed. The number of registered cases declined from 16,391 in 2014 to 6548 in 2023, corresponding to a cumulative reduction of 60.1% and an AAPC of -9.7% per year. TB incidence decreased in both sexes, although rates remained consistently higher among men. Over time, the peak incidence shifted toward older age groups, particularly among men. The proportion of new cases increased to 80.1% by 2023, while relapses and treatment failures declined. In multivariable analysis, unfavorable treatment outcomes were independently associated with male sex (aOR 1.25), older age, relapse, treatment after interruption, prior treatment failure, smear-positive disease (aOR 1.60), combined pulmonary and extrapulmonary involvement, and disseminated TB (ICD-10 A19). The risk of unfavorable outcomes increased during 2020-2021 and declined in 2022-2023. Conclusions: Kazakhstan has achieved a substantial and sustained reduction in TB incidence over the past decade. Nevertheless, marked demographic and clinical disparities persist, particularly among men, older patients, smear-positive cases, and individuals with prior or interrupted treatment. Targeted interventions focused on these high-risk groups may further improve treatment outcomes and support continued progress toward TB control.