Association between tuberculosis diagnosis delay and respiratory health and well-being among tuberculosis survivors in Cambodia: a prospective cohort study.

BACKGROUND: Although tuberculosis (TB) treatment success rates are high globally, growing evidence indicates that many TB survivors experience persistent respiratory symptoms, impaired quality of life and reduced well-being after treatment completion. Delayed TB diagnosis may exacerbate these long-term consequences by prolonging untreated disease and lung injury. However, longitudinal evidence linking diagnosis delay to longer-term outcomes remains limited. This study examines the association between TB diagnosis delay and respiratory health, quality of life and mental health among TB survivors in Cambodia. METHODS: A prospective cohort study of adults with newly diagnosed TB was conducted with a baseline in 2022 and 1 year and 2 year follow-ups. TB diagnosis delay was defined as the time from symptom onset to diagnosis and categorised as short or long using the median (64 days). Outcome variables included respiratory health, quality of life and depressive symptoms, assessed with the St George's Respiratory Questionnaire for Chronic Obstructive Pulmonary Disease (SGRQ-C), WHO Quality of Life-Brief (WHOQOL-BREF) and Centre for Epidemiologic Studies Depression Scale, 10-item version (CES-D-10), respectively. Linear mixed-effects models, adjusted for potential confounders, were applied. RESULTS: Among 712 participants at baseline, the long-delay group had worse respiratory health before treatment completion and over 2 years, with higher SGRQ-C total (β=4.37, 95% CI 1.10 to 7.64), symptom (β=5.83, 95% CI 2.34 to 9.31) and activity scores (β=6.95, 95% CI 2.67 to 11.23) than the short-delay group. Long delay was also associated with poorer psychological (β=-3.17, 95% CI -5.31 to -1.03) and environmental domains (β=-1.74, 95% CI -3.07 to -0.4) of the quality of life but not with its physical and social domains or depressive symptoms. The differences between the groups remained relatively stable over time. CONCLUSIONS: TB diagnosis delay may influence recovery beyond treatment success, highlighting the importance of early case detection and integrated post-treatment support in high-burden settings.