Incidence and Outcomes of Active Tuberculosis In Solid Organ Transplant Recipients: A 16-Year Review

Background: Tuberculosis (TB) is a significant opportunistic infection in solid organ transplant recipients (SOTR). Therapy for TB is complex in this population due to drug interactions and toxicity. Data are lacking regarding incidence and outcomes of active TB in SOTR in low prevalence areas.

Methods: We performed a retrospective review of all SOTR diagnosed with active TB at a large Canadian transplant center between January 1, 2000 and December 31, 2015. Diagnosis of TB was based on positive culture or PCR. 

Results: We identified 33 active TB cases out of 8372 organ transplants performed (0.4%). Incidence of TB was 59 per 100,000 transplant-years. This was greater than the incidence in general population (4.5 cases per 100,000 person-years in 2012; Relative Risk 13.1). TB incidence for kidney, liver, heart and lung transplants was 34, 84, 65, 117 cases per 100,000 transplant- years, respectively. The median time to diagnosis after transplantation was 8 months; 20/33 (61%) patients were diagnosed within the first year after transplant. The majority of patients (64%) were born in countries of high TB prevalence while 18% were born in Canada and 18% were unknown. Pre-transplant screening for latent TB was not documented for any patient. Nineteen patients (58%) had pulmonary TB and 15% had extra-pulmonary TB only; 21% had disseminated TB. No TB isolate was resistant to first-line medications. Patients were treated for a median of 9 months (range 9.25-30). Thirty (91%) patients had both isoniazid and rifampin/rifabutin respectively included in their treatment regimen. Seventeen (47%) also included moxifloxacin. 67% of patients had at least one adverse effect of therapy including hepatotoxicity (39%), rash (6%) and peripheral neuropathy (6%). Graft rejection occurred in 6 (18%) and one patient (3%) had graft loss. One-year mortality in this population was 7/33 patients (21%).

Conclusion: We describe the largest cohort of active TB in SOTR from a low prevalence area. Active TB occurred early post-transplant likely due to reactivation of latent disease. Screening for TB in low prevalence countries should be routine prior to transplant to prevent such cases especially in those patients originating from countries of high TB prevalence.