Diagnosis and treatment of latent tuberculosis infection in liver transplant recipients in an endemic area

Background. Treatment of latent tuberculosis infection (LTBI) with isoniazid is recommended for transplant recipients with positive tuberculin skin test (TST). However, TST could be an imperfect identifier of LTBI in this population. In addition, the risk of isoniazid hepatotoxicity could be high in liver transplant recipients (LTR). A retrospective cohort study was performed to evaluate the diagnosis and treatment of LTBI in LTR. Methods. Charts of all 547 patients who received primary liver transplantation at a University Hospital in Spain between 1988 and 1998 were reviewed. Results. TST was performed in 373 patients (71%) before transplantation. The result was positive in 89 (24%). The median follow-up after transplantation was 49 months. None of the TST-positive patients developed tuberculosis (TB), but 5 out of 284 patients with negative TST (1.76%) had active TB (P = 0.6). Twenty-three patients received isoniazid as treatment of LTBI according to the decision of the attending physician. None of these patients developed TB, but 4 of them (17%) presented isoniazid hepatotoxicity. Among patients who did not receive isoniazid, 2 out of 21 (9.52%) with radiologic previous TB developed active TB versus 0.44% (2/452) among the remaining patients (relative risk [RR], 27.8, 95% Cl, 3.2-147). Conclusions. Treatment of LTBI with isoniazid can not be recommended to LTR on the basis of a positive TST because it is an imperfect identifier of patients at risk of TB. LTR with radiologic features of previous TB are at higher risk of posttransplant active TB. Isoniazid-related hepatotoxicity is more frequent among LTR than in the general population.