Dynamic tuberculosis infection pattern: high conversion and reversion among persons with type 2 diabetes in India

A multicentric study in eight primary health centres across four geographically diverse regions of India (Puducherry, Telangana, Maharashtra, and Chandigarh).

Among persons with diabetes (PWD) registered for care, to determine the conversion and reversion rates of tuberculosis infection (TBI) at 6 and 12 months and its associated factors.

Cohort study with serial interferon-gamma release assay (IGRA) at baseline and at 6 and 12 months after excluding active TB. Conversion (baseline TBI negative to positive) and reversion (baseline TBI positive to negative) was assessed, and modified Poisson regression was used to identify associated factors.

Of 750 recruited, 748 PWD underwent baseline IGRA (excluding two newly diagnosed TB), and 339 (45%) were positive. At 12 months, reversion among baseline positives was 38% (95% confidence interval [CI]: 32-44), while conversion among baseline negatives was 22% (95% CI: 17-26). Tobacco non-use was associated with reversion, while older age (≥60 years) and lower body mass index compared to obesity (>25 kg/m²) were associated with conversion.

High rates of IGRA conversion and reversion among PWD highlight the dynamic nature of TBI and question the utility of single time-point TBI testing for making decisions regarding initiation of TB preventive therapy.