Multimorbidity in tuberculosis and its impact on health and treatment outcomes: A prospective cohort study

Multimorbidity - the co-existence of two or more long-term health conditions (LTCs) - is increasingly common in low- and middle-income countries. Yet, in the African region, its prevalence in people with tuberculosis (TB) and its impact on treatment outcomes remain poorly characterised. We sought to determine the prevalence and patterns of multimorbidity and its impact on health and treatment outcomes in people with TB in Kampala, Uganda, and to evaluate cascades of care for hypertension, diabetes mellitus, HIV and mental health conditions. This was a prospective cohort study of adults ([≥]18 years) commencing anti-TB treatment at four clinics in Kampala between June 2024-June 2025. LTCs were identified through self-report, validated screening tools, clinical examination and blood analysis, using definitions informed by the Ho et al. Delphi consensus. Multimorbidity was defined as TB plus two or more LTCs. Participants were followed to month six to assess health-related quality of life (HRQoL), physiological status (National Early Warning Score (NEWS)), sputum bacillary clearance (TB-Molecular Bacterial Load Assay (TB-MBLA)) and WHO-defined treatment outcomes. Descriptive statistics were used to examine the prevalence and patterns of multimorbidity and evaluate cascades of care. The effect of multimorbidity on health and treatment outcomes was assessed using regression models. Among 254 adults with TB, the prevalence of multimorbidity was 39.4% (95% CI 33.3-45.7%); only 22.4% had TB with no co-existing condition. The most prevalent LTCs were HIV (44.1%), undernutrition (39.8%) and depression (16.1%). Care cascades revealed substantial gaps in screening and diagnosis (HIV, diabetes mellitus and mental health conditions) and treatment (hypertension). At enrolment, multimorbidity was associated with worse NEWS (adjusted mean difference 0.88, 95% CI 0.36 to 1.42) and HRQoL (adjusted mean difference in HRQoL score -10.75, 95% CI -16.77 to -4.73). Multimorbidity was associated with a higher risk of a positive sputum TB-MBLA at month 2 and a higher risk of an unsuccessful TB treatment outcome (adjusted risk difference 9.88%, 95% CI 2.59 to 17.17). All deaths occurred among participants with multimorbidity. Multimorbidity affected two in five adults with TB in this cohort and was associated with worse health at diagnosis and poorer treatment outcomes. National TB programmes are well placed to identify and manage co-existing LTCs, but care cascades show gaps at different stages for different conditions, underscoring the need for tailored, integrated approaches.