An increased incidence of tuberculosis (TB) in patients under anti-TNF-α therapy has been reported, but outcome compared with TB in the general population are unknown.
Patients who had active tuberculosis while taking anti-TNF-α drugs were studied and compared with a control group of community-acquired TB matched for sex, age and data of TB.
Twenty-five cases of TB were reported from a cohort of 765 patients under anti-TNF-α from 2001 to 2012. The incidence of TB per 100,000 patient-years was estimated to be 1337, 792 and 405 respectively for those on infliximab, adalimumab and etanercept. Twelve patients had inflammatory bowel disease, ten had rheumatologic diseases and three had psoriasis. From the 17 patients screened for latent TB before anti-TNF-α, three were treated with isoniazid. TB was diagnosed 1-108 months after starting anti-TNF-α, being the median time six, seven and 89 months respectively for those on infliximab, adalimumab and etanercept. Sixty per cent of the cases had extra-pulmonary TB. No deaths occurred in the case groups, while two died in control TB patients. Patients on anti-TNF-α drugs had more frequent extra-pulmonary TB, fever on presentation, higher mean C-reactive protein and lower positive rate of acid-fast bacilli.
TB may still occur in those with negative testing, some of them probably representing new infections instead of reactivations. Three out of 25 patients had TB in spite of previously treated LTB, although, the outcome of TB was not worse than in the general population.