Avalilação PREreview de Time-to-Tuberculosis disease diagnosis after completion of Tuberculosis preventive therapy among people living with HIV on Antiretroviral Therapy in Eastern Uganda: A retrospective cohort study

Summary

This preprint examines the time from completion of tuberculosis preventive therapy to later TB diagnosis among people living with HIV on ART in Eastern Uganda. The study uses routine program data from three TASO Centres of Excellence in Mbale, Soroti, and Tororo and includes 670 people who developed TB after completing TPT. I think this is an important and useful study because it addresses a practical TB/HIV program question in a high-burden setting.

Main contribution

The main contribution is that the paper describes the timing and characteristics of TB cases occurring after TPT completion. The comparison across Mbale, Soroti, and Tororo is also useful because it may point to facility-level differences in screening, follow-up, diagnosis, or local TB exposure.

Strengths

A major strength is the good use of routine program data from electronic medical records, TB registers, and patient files. The operational definitions are clear, and the descriptive epidemiology is easy to follow. I also like the size of the study: 670 post-TPT TB cases is a meaningful real-world sample for programmatic analysis. The high proportion of bacteriologically confirmed TB cases also strengthens the validity of the findings. The paper has a clear policy implication because it supports continued TB screening after TPT completion and raises the question of repeat or extended TPT for higher-risk groups.

Major comments

One point that could be clarified is the study design and framing. I may be misunderstanding the authors’ intent, but it is not fully clear whether the study is meant to estimate TB risk after TPT or to describe people who developed TB after TPT. Since the analysis only includes people who already developed TB after completing TPT, it cannot estimate TB risk or TPT failure rates among all PLHIV who completed TPT.

The paper is strongest as a description of timing and characteristics among post-TPT TB cases. I suggest the authors make this distinction clearer in the abstract, discussion, and conclusion to avoid overinterpreting the findings.

The definition of early TB as diagnosis within 1.5 years after TPT completion also needs more explanation. The authors should explain why this cutoff was chosen. The finding that viral suppression was associated with higher odds of early TB should also be interpreted carefully, since this may reflect better clinic engagement, more frequent screening, or unmeasured confounding rather than a biological increase in TB risk.

Minor comments

The limitations section should more directly mention the case-only design. Some language around “TPT durability” should be softened because the study does not include all people who completed TPT. The site differences, especially the lower odds of early TB at Soroti, are interesting and could be discussed more clearly in relation to program quality, diagnostic practices, or local TB transmission.

Overall assessment

Overall, I think this is a useful preprint with real public health value for TB/HIV programs in Eastern Uganda and similar settings. I like the use of routine program data, the large sample, the clear operational definitions, and the comparison across the three TASO sites. The main improvement would be to frame the conclusions more carefully around what the study design can actually show.

Competing interests

The author declares that they have no competing interests.

Use of Artificial Intelligence (AI)

The author declares that they used generative AI to come up with new ideas for their review.