Latent tuberculosis infection and diagnostic performance of the tuberculin skin test among type 2 diabetics in Sana'a city, Yemen.

Background: Tuberculosis (TB) is one of the most widespread infectious diseases worldwide, typically persisting in the body as a latent TB infection (LTBI). Patients with type 2 diabetes have an increased risk of LTBI progressing to active TB. Therefore, this study determined the prevalence and predictors of LTBI and assessed the agreement between tuberculin skin test (TST) and interferon-gamma release assay (IGRA) in diagnosing LTBI among type 2 diabetics in Sana'a city, Yemen.

Methods: A cross-sectional study was conducted among 150 type 2 diabetics in private health facilities in Sana'a in 2023. Data about demographics, diabetes-related characteristics, and potential risk factors for LTBI were collected using a structured questionnaire. Patients were then screened for LTBI using TST and IGRA. Univariate analysis was used to identify LTBI-associated risk factors, and multivariable binary logistic regression was used to identify independent predictors of LTBI. The agreement between TST and IGRA for diagnosing LTBI was assessed using Cohen's kappa coefficient (κ).

Results: LTBI was prevalent among 29.3% of type 2 diabetics using both types of tests (25.3% with IGRA and 21.3% with TST). Male gender was an independent predictor of LTBI (AOR = 4.4, 95% confidence interval: 1.30-15.08; P = 0.018). However, being employed (AOR = 0.3, 95% CI: 0.09-0.75; P = 0.013) and longer duration since diabetes diagnosis (AOR = 0.3, 95% CI: 0.12-0.98; P = 0.046) were identified as predictors of lower LTBI risk. The agreement between TST and IGRA for the diagnosis of LTBI was 88%, with a good and statistically significant agreement between the two test types (κ = 0.670; P < 0.001).

Conclusions: LTBI is common among type 2 diabetics seeking medical care in Sana'a city, with about one-third of them possibly being latently infected. A higher LTBI risk can be predicted among males, while a lower risk can be predicted among those employed or being diagnosed with diabetes for at least five years. The TST shows good agreement with IGRA in diagnosing LTBI among type 2 diabetics, supporting its continued use as a cost-effective and easily accessible test for diagnosing LTBI in the country.