Risk factors for transplant-associated thrombotic microangiopathy and mortality in a pediatric cohort

Transplant-associated thrombotic microangiopathy (TA-TMA) is a well-recognized complication of hematopoietic cell transplantation (HCT). Diagnosis is challenging and in the absence of a tissue biopsy, TA-TMA is provisionally diagnosed by meeting clinical criteria. In this study, we describe the prevalence, outcomes, and risk factors for meeting 2 different diagnostic criteria for TA-TMA and for increased transplant-related mortality (TRM). In this retrospective study of 307 pediatric HCT patients, records were reviewed for the first 100 days after HCT. Patients who were diagnosed with TA-TMA by a provider during this time were included. In addition, the Cho et al criteria (2010) and Jodele et al (2014) TA-TMA criteria were applied retrospectively. Eight patients (2.6%) were diagnosed with TA-TMA by their provider. However, on retrospective review, 20% and 36% met the Cho and Jodele criteria for TA-TMA, respectively. Overall survival was significantly worse (P < .0001) and TRM was significantly higher in patients who met criteria for TA-TMA (MC-TA-TMA) (P < .0001). After controlling for comorbid conditions, MC-TA-TMA (hazard ratio [HR], 10.9; P = .0001) and grade 3/4 acute graft-versus-host-disease (aGVHD) (HR 3.5; P = .01) remained independently associated with increased TRM. Among allogeneic HCT recipients, features associated with an increased risk for MC-TA-TMA included ≥2 HCT, concurrent grade 3/4 aGVHD and concurrent infections. Among patients who MC-TA-TMA, LDH ≥2 times the upper limit of normal (P = .001), the need for ≥2 antihypertensive medications (P < .0001), and acute kidney injury (P = .003) were associated with significantly increased TRM.