Risk factors and clinical outcomes of tuberculosis among kidney transplant recipients in high endemic country

Background: Tuberculosis (TB) is considered as a challenge issue in solid organ transplant recipients because of high morbidity and mortality. Active TB after transplant mostly occurs from reactivation of latent infection. Understanding risk factors and clinical information of TB may provide an appropriate prevention and treatment strategies in this specific patient population, however data from high endemic area is scarce.

Methods: A matched single-center, case-control study was conducted in our institute. Cases were defined as newly diagnosed confirmed or clinical active TB in patients who underwent kidney transplant (KT) between April 1992 and October 2018. For each case, 5 controls were matched by age and sex. Risk factor associated with TB was determined using univariate and multivariate conditional logistic regression.

Results: Between study period, KT was performed in 787 patients. Twenty-seven patients (3.43%) were diagnosed with active TB including 20 confirmed and 7 clinical diagnosed cases. The global incidence of TB in our population was 315 cases per 100 000 patients per year. Among 27 cases, pulmonary involvement was the most common (48.1%) followed by disseminated (18.5%), extrapulmonary (14.8%), pleura (11.1%) and pleuropulmonary (7.4%) TB. Allograft rejection was significantly associated with active TB (P < .001). The median onset duration of infection was 17 months (IQR, 4-59 months) after KT. Twenty-four (88.9%) patients received rifampicin containing regimen for treatment with median duration of 10 months (IQR, 6-12 months). All patients were cured after complete treatment, however those with TB remained having unfavorable outcomes including higher all-cause mortality and graft loss.

Conclusions: Incidence rate of TB in KT recipients is higher than normal population. Allograft rejection was identified as a significant risk factor. Increase unfavorable outcomes including graft loss and mortality were also observed among patients with TB.