Prevalence of pulmonary tuberculosis in rheumatoid arthritis

Abstract

Background: Respiratory tract infection is an important source of morbidity in patients with RA. The exact prevalence of pulmonary infection in this population is reported variably. Agents that block the action of tumour necrosis factor (TNFα) etanercept, infliximab and adalimumab are established as effective agents in the treatment of rheumatoid arthritis, especially in patients with disease unresponsive to standard disease modifying antirheumatic drugs (DMARDs). In countries like India, with high prevalence of tuberculosis the estimated risk of reactivation is estimated to be 10% while on treatment with tumour necrosis factor α inhibitors. This study is aimed to find the prevalence of pulmonary tuberculosis in rheumatoid arthritis patients. Methods: Patients with definite diagnosis of rheumatoid arthritis attending the rheumatology clinic and chest clinic of Calicut Medical College during the study period were evaluated for evidence of pulmonary tuberculosis. Total of 217 patients were included in this study. Results: 18 patients had evidence of pulmonary tuberculosis. 5 patients had active disease and 13 patients had evidence of healed pulmonary tuberculosis. The prevalence of pulmonary tuberculosis was 8.3%. This is much higher than the prevalence in the Indian population which is 13-25 per thousand. Of the 5 patients who had active disease 3 patients were on leflunamide for 1 year or more. On analysis it was found that patients on leflunamide were at an increased risk of developing tuberculosis (p <0.001) and the risk estimate showed an odds ratio of 14.2. Conclusions: Prevalence of pulmonary tuberculosis in the study population was found to be 8.3%. In countries with high prevalence of latent and active tuberculosis, rheumatoid arthritis patients should be carefully monitored for pulmonary tuberculosis before and during the treatment with immunosuppressive drugs.