The evaluation of latent tuberculosis in rheumatologic diseases for anti-TNF therapy: experience with 192 patients

It is recommended to evaluate the presence of latent tuberculosis infection (LTBI) before initiating antitumor necrosis factor α (anti-TNF) therapy for rheumatologic diseases. We aimed to present the follow-up results of 192 patients with rheumatologic diseases before anti-TNF therapy for LTBI. We enrolled 192 patients who were given anti-TNF therapy for their rheumatologic diseases between April 2005 and January 2008. The demographic characteristics of the patients were recorded. Chest X-ray was obtained and tuberculin skin test (TST) was performed in all patients before anti-TNF therapy. LTBI was assessed by detailed history of close contact with infectious cases within the last year, abnormal chest radiography, and positive TST (≥5 mm) before initiating anti-TNF therapy. Patients with anti-TNF therapy were followed with 2-month intervals for active tuberculosis by pulmonary and extrapulmonary symptoms, physical examination, and chest X-ray. Of 192 patients, 104 (54.2%) patients were women, age (mean ± SD) 43.1 ± 12.7 years and 88 (45.8%) patients were men, age (mean ± SD) 39.3 ± 11.2 years. Ninety-one (47.4%) of them had rheumatoid arthritis (RA); 92 (47.9%) had ankylosing spondylitis (AS), and nine (4.7%) had psoriatic arthritis. Isoniazid treatment was started in 129 (67.2%) patients in whom LTBI was detected. No significant difference was observed for TST positivity (TST ≥ 5 mm) between the patients with RA and AS (p = 0.101). Similarly, no significant difference was also observed for TST positivity between the patients who received immunosuppressive therapy and those who did not (p = 0.154). Only three (1.6%) patients developed active tuberculosis at the study period. We suggested that in despite of the presence of rheumatologic disease and/or immunosuppressive therapy, TST is an acceptable and available diagnostic test for detecting LTBI before anti-TNF therapy.