Results
From 2000 to 2012, a total of 12369 unique pediatric patients who received HSCT were identified. Among these 93 (0.8%) children were identified to have the diagnosis of TMA. Overall, there was an increasing trend of TMA diagnosis seen in our cohort over the years, with the highest percent occurrence in 2012 (p = 0.0125).
In Table 1, we identified 12 cases of TMA (12.9%) in patients who received an autologous HSCT, 78 cases (83.9%) in patients who received an allogeneic transplant, and 3 cases (3.2%) who were unspecified. Furthermore, 25 cases of TMA (32.1%) were from a bone marrow transplant, 41 cases (52.6%) were after a peripheral blood transplant, and 12 cases (15.4%) occurred after a cord blood transplant.
TMA was significantly associated with allogeneic HSCT (p=<0.001), PBSCT (p=0.045), CMV (p=<0.001), HHV6 (p=<0.001), fungal infection (p=<0.001), GVHD (p=<0.001) and VOD (p=0.01). Additionally, TMA was significantly associated with hypertension (p=<0.001), and renal failure (p=<0.001) (Table 1). Multivariate logistic regression analysis of mortality using age, gender, HSCT type, CMV, HHV6, fungal infection and plasmapheresis showed only HHV6 was an independent risk factor associated with increased mortality in patients with TMA (Hazard Ratio: 2.86 [1.01, 8.39], p=0.05)
The mortality was significantly higher in patients with TMA compared to those without (30.1% vs. 12.2%, p=<0.001, Table 1). Additionally, median time (days) to mortality following HSCT was shorter in patients with TMA than those without (754 [365, 1614] vs. 1439 [552, 2847], p=<0.0001).