Positividad de tuberculina en artritis reumatoide Frequency of positivity of the tuberculin intradermorreaction test in a cohort of patients with rheumatoid arthritis before starting or switching biological therapy

Introduction: Rheumatoid arthritis is an autoimmune, chronic and deforming condition associated with disability. Rheumatoid arthritis patients are considered having immunosuppression being at high risk of developing tuberculosis. The tuberculin skin test is used as a screening test in candidates to receive biological therapy. Objective: To evaluate the frequency of positivity of the tuberculin skin test in a cohort of patients with rheumatoid arthritis. Materials and methods: Descriptive cross-sectional study including patients with rheumatoid arthritis in whom the tuberculin skin test was performed, prior to the start or at the time of the change of biological therapy. The patients were in moderate or severe disease activity and were candidates for initiation or change of biological therapy. The value of >6mm was defined as the cut-off point for a positive tuberculin skin test. A descriptive analysis for each of the variables included was performed. Results: In total, 261 patients with rheumatoid arthritis were included, 92% women, average age 55 years (SD 13.92) and diagnosis time 12.3 years (SD 8.54). The frequency of a positive tuberculin skin test was 15.71% (n = 41). From the patients having a positive test (n=41), the test had been previously performed in 9 patients (between 1-6 years before) and the result in all of them was negative. Tuberculin skin test positive patients (n=41) were receiving glucocorticoids (43.9%) and methotrexate (100%). Conclusions: The frequency of positivity of the tuberculin skin test in Colombian patients with diqgnosis of RA is reported (16%). Strategies aimed to the optimal identification of this condition and the proper initiation of treatment-initiation are recommended in order to reduce the risk of tuberculosis reactivation.