Prevalence of latent tuberculosis in patients with rheumatological diseases exposed to biologic drugs and small molecules: A study based on the BIOBADAMEX national registry

Introduction Latent tuberculosis infection (LTBI) represents a challenge in patients with rheumatic diseases treated with immunological drugs, including TNF-α inhibitors, due to the increased risk of progression to active tuberculosis. Identifying the prevalence of LTBI and its associated factors is key to improving screening and prevention of this condition in this vulnerable population. Objective Primary: To determine the prevalence of LTBI in Mexican patients with rheumatic diseases treated with biologic DMARDs or small molecules. Secondary: To identify factors associated with LTBI, considering sociodemographic, clinical, and geographic characteristics. Materials and methods This retrospective, descriptive, cross-sectional study was based on 1464 patients included in the BIOBADAMEX database (June 2016-October 2024). All patients with a confirmed diagnosis of rheumatological diseases who had initiated treatment with biologic therapy or small molecules were included, regardless of age or diagnosis. Diagnostic tests included in the registry (tuberculin skin test, tuberculin booster, and quantiferon for tuberculosis) were analyzed to detect latent thrombolytic disease (LTBD). Sociodemographic, clinical, and laboratory variables were analyzed using descriptive statistics and logistic regression models, considering a significance level of 0.05. Results The prevalence of LTBI was 10.1% among the patients evaluated. A positive association was identified with male sex (OR: 2.64; 95% CI: 1.77, 3.95) and residence in Northern Mexico (OR: 4.74; 95% CI: 1.46, 15.32). BCG vaccination showed a negative association (OR: 0.61; 95% CI: 0.38, 0.98). No significant associations were identified with the type of drug used or relevant comorbidities, except for a negative association with hypercholesterolemia (OR: 0.25; 95% CI: 0.08, 0.81). Conclusion The study found that the prevalence of latent tuberculosis infection (LTBI) in Mexican patients with rheumatic diseases who are about to begin biologic therapy is consistent with the prevalence of LTBI in the Mexican population. Screening these patients for tuberculosis before initiating biologic therapy allows for the identification of patients with LTBI and enables appropriate management so they can begin biologic therapy of any mechanism of action. This screening should be expanded and applied to 100% of patients starting biologic therapy, paying particular attention to patients with associated risk factors.