Association between tuberculosis diagnosis delay and respiratory health and well-being among tuberculosis survivors in Cambodia: a prospective cohort study.
Eng S, Prem K, et al. • BMJ open respiratory research • 2026
TB diagnosis delay was associated with worse respiratory health and poorer psychological and environmental quality of life over 2 years among TB survivors in Cambodia, with differences between long- and short-delay groups remaining relatively stable over time.
Key Findings
Results
Longer TB diagnosis delay was associated with worse overall respiratory health over 2 years compared to shorter delay.
TB diagnosis delay was defined as time from symptom onset to diagnosis, categorized as short or long using the median of 64 days.
The long-delay group had higher SGRQ-C total scores than the short-delay group (β=4.37, 95% CI 1.10 to 7.64), indicating worse respiratory health.
Higher SGRQ-C scores indicate worse respiratory health outcomes.
Linear mixed-effects models adjusted for potential confounders were used across baseline, 1-year, and 2-year follow-ups.
712 participants were enrolled at baseline in 2022.
Results
Longer TB diagnosis delay was associated with worse respiratory symptom scores over the study period.
The long-delay group had higher SGRQ-C symptom scores compared to the short-delay group (β=5.83, 95% CI 2.34 to 9.31).
Symptom scores were assessed before treatment completion and over 2 years of follow-up.
The SGRQ-C was used to assess respiratory health outcomes.
Results
Longer TB diagnosis delay was associated with worse respiratory activity limitation scores over the study period.
The long-delay group had higher SGRQ-C activity scores compared to the short-delay group (β=6.95, 95% CI 2.67 to 11.23).
The activity domain of the SGRQ-C reflects limitations in physical activities due to respiratory symptoms.
This was among the largest effect sizes observed across all outcome domains.
Results
Longer TB diagnosis delay was associated with poorer psychological quality of life but not with physical or social quality of life domains.
The long-delay group had lower WHOQOL-BREF psychological domain scores (β=-3.17, 95% CI -5.31 to -1.03), indicating worse psychological quality of life.
No statistically significant association was found between diagnosis delay and physical or social domains of quality of life.
Quality of life was assessed using the WHO Quality of Life-Brief (WHOQOL-BREF) instrument.
Lower scores on WHOQOL-BREF domains indicate poorer quality of life.
Results
Longer TB diagnosis delay was associated with poorer environmental quality of life domain scores.
The long-delay group had lower WHOQOL-BREF environmental domain scores (β=-1.74, 95% CI -3.07 to -0.41).
The environmental domain of WHOQOL-BREF covers factors such as physical safety, access to health services, and living environment.
This effect was smaller in magnitude than the psychological domain association.
Results
TB diagnosis delay was not significantly associated with depressive symptoms over the 2-year follow-up period.
Depressive symptoms were assessed using the Centre for Epidemiologic Studies Depression Scale, 10-item version (CES-D-10).
No statistically significant association was found between long diagnosis delay and CES-D-10 scores.
This null finding contrasts with the associations observed for respiratory health and psychological quality of life domains.
Results
The differences in respiratory health and quality of life outcomes between long- and short-delay groups remained relatively stable over the 2-year follow-up.
Follow-up assessments were conducted at 1 year and 2 years after baseline.
The authors note that 'the differences between the groups remained relatively stable over time,' suggesting the gap did not narrow during the observation period.
This pattern indicates that longer delay has a persistent rather than transient effect on outcomes after diagnosis and treatment.
Methods
The study enrolled 712 adult participants with newly diagnosed TB in Cambodia using a prospective cohort design.
Baseline data were collected in 2022, with follow-ups at 1 year and 2 years.
Participants had newly diagnosed TB at enrollment.
The median TB diagnosis delay was 64 days, which was used as the cutoff to define short versus long delay groups.
The study was conducted in Cambodia, a high TB burden setting.
What This Means
This research suggests that how long it takes for a person to receive a tuberculosis (TB) diagnosis after symptoms begin has lasting effects on their health and well-being, even after they complete TB treatment. The study followed 712 adults newly diagnosed with TB in Cambodia over two years, comparing those who waited longer than 64 days for a diagnosis (the 'long-delay' group) to those diagnosed sooner. People in the long-delay group had notably worse breathing-related health—more symptoms and greater difficulty with physical activities due to respiratory problems—and reported lower psychological and environmental quality of life throughout the entire two-year follow-up period.
Importantly, the gap between the two groups did not close over time, meaning that people who experienced longer delays before diagnosis did not 'catch up' in their recovery compared to those diagnosed more quickly. However, longer diagnosis delay was not linked to differences in depression scores, physical quality of life, or social quality of life. This suggests that the harm from delayed diagnosis is specific to certain aspects of health, particularly lung function and psychological well-being.
This research suggests that getting people diagnosed with TB as early as possible is important not just for curing the infection, but also for preserving long-term respiratory health and quality of life. The findings also point to a need for ongoing support services for TB survivors—especially those who experienced delays in diagnosis—even after they have successfully completed treatment. These results are particularly relevant for countries with high TB burdens, where delays in diagnosis remain common.
Eng S, Prem K, Teo A, Tuot S, Pall C, Tep S, et al.. (2026). Association between tuberculosis diagnosis delay and respiratory health and well-being among tuberculosis survivors in Cambodia: a prospective cohort study.. BMJ open respiratory research. https://doi.org/10.1136/bmjresp-2026-004413