The incidence, clinical characteristics and risk factors of tuberculosis among renal allograft recipients at National Kidney and Transplant Institute

ABSTRACT

OBJECTIVE: Renal allograft recipients are at higher risk of developing tuberculosis (TB) as compared to the general population. The infection also carries with it a significant morbidity and mortality. However, data is limited regarding its incidence and risk factor analysis in our setting. This study determined the incidence, characteristics and risk factors of post-transplant TB in National Kidney and Transplant Institute (NKTI).METHODS: This is a retrospective study involving chart review of 1,621 renal allograft recipients from 2003-2009. We recorded demographic information, transplant characteristics, median time to diagnosis of TB and forms of TB.RESULTS: The incidence of TB in renal allograft recipients is 2.6%. Median time to diagnosis of TB after transplant is 21 months (one to 105 months). Risk factors identified in this study were previous history of TB (OR 4.15, 95% CI 1.4-12.2), one episode of rejection (OR 2.33, 95% CI 1.2-4.6) and subsequent use of methylprednisolone as antirejection therapy (OR 2.36, 95% CI 1.3-4.4). Patients given a tacrolimus based regimen (OR 0.5, 95% CI 0.24-1.03) and those without episode of rejection (OR 0.43, 95% CI 0.22-0.84) had less tendency to develop post-transplant TB. There were no sufficient evidence to prove association between onset of TB and use of isoniazid prophylaxis, use of induction immunosuppression and type of immunosuppression. Eighty one percent (81%) had pulmonary and 19% had extrapulmonary forms of TB.CONCLUSION: Incidence of TB among renal allograft recipients is lower as compared to other high TB burden countries but is still higher as compared to the general Filipino population. The study identified multiple risk factors for post-transplant TB. Prevention of these diseases and identification of patients at risk are as important as early diagnosis and treatment of post-transplant TB.