Background The Anti Tumour Necrosis Factor (aTNF) therapy in Rheumatics Diseases (RD) had changed the prognosis of theses conditions in the last decade. Unfortunately, aTNF therapy is associated a high-risk rate of infections, especially active tuberculosis (TB) . The use of tuberculin skin test (TST) to detect and treat latent tuberculosis (LTBI) before to initiate aTNF therapy had reduced the risk of TB by 75 to 95% . However, multiple factors as prevalence of TB by country, malnutrition, anergy, immunosuppressors, advanced age, BCG vaccination between others compromise the sensitivity and specificity (falsely negative and positive results) of the test to distinguish between remote and recent disease. These factors are also associated with frequency and progression of LTBI to TB and differ between populations . Few studies have been performed in Mexicans with RD under aTNF therapy .
Objectives To determine the frequency of TB and LTBI, TST conversions and associated factors during aTNF therapy in patients with RD from a Mexican cohort.
Methods 151 patients (≥14 years) from a Mexican cohort from 2011 to 2016 were examined. Ankylosing Spondylitis (AS), Juvenile idiopathic arthritis (JIA), Psoriatic Arthritis (PsA) and Rheumatoid Arthritis (RA) cases fulfilled Amor, ILAR, CASPAR and ACR/EULAR 2010 criteria respectively. TB and LTBI (TST induration ≥5 mm recorded to 72 hours) diagnosis occurred before to start aTNF therapy. Conversions happened in the second TST. Demographic factors, comorbidities and pharmacologic treatments were examined for patients without and with TB, LTBI and TST conversions under aTNF therapy. Variables were examined by univariable and multivariable analyses.
Results Of 151 patients, 71 had AS, 68 had RA, 9 had JIA and 3 had PsA; of them 53% were women. The mean age [standard deviation (SD)] was 47.1 (12.5) years. The mean of time at onset of RD [standard deviation (SD)] was 12.3 (8.7) years. A total of 5 patients had TB for a crude prevalence of 3.3% and three of them used infliximab. TB was more common in patients with first TST negative and after TST conversion (OR 6.97, 95% CI 1.36–35.5, p=0.019). LTBI was detected in 57 (37.7%) patients and was more associated with lower wage (OR 0.2, 95% CI 0.52–0.98, p=0.047), to be healthcare workers (OR 57.1, 95% CI 2.67–1219.50, p=0.010), and smoking (OR 30.1, 95% CI 5.40–167.24, p≤0.005). TST Conversions were presented in 43 (28.5%) cases and were more associated with treatment with ≥15 mg/d of prednisone (OR 3.7, 95% CI 1.54–9.21, p≤0.005). No differences were found for patients with BCG vaccination and previous TB before aTNF therapy
Conclusions This study suggests that patients with RD in this cohort from Mexico have a high prevalence of TB, LTBI and TST conversions compared to other studies. Also lower wage, to be healthcare workers and smoking were associated with LTBI, and TST conversion occurred more associated to use higher dose of glucocorticoids. The clinical significance of these TST conversions is unclear at the moment.
J Rheumatol 2013;40;1938–1940;
Clinical Infectious Diseases 2011;52(8):1031–1037;
Rheumatol Int (2015) 35:1555–155.
Disclosure of Interest None declared