Pre-Transplant Glomerular Hyperfiltration Is Not Associated with Renal Morbidity or Overall Mortality in Pediatric Patients

Abstract

IntroductionGlomerular hyperfiltration is defined as an abnormally high GFR. Consensus is lacking as to what GFR constitutes hyperfiltration, and its role as a risk factor for acute kidney injury (AKI) and chronic kidney disease (CKD) is poorly understood. It has been shown that decreased GFR prior to transplant is associated with subsequent AKI, but there are no studies looking at the effect of pre-transplant hyperfiltration in pediatric transplant patients.ObjectivesDetermine whether pre-transplant hyperfiltration is a risk factor for renal morbidity and overall mortality in pediatric SCT patients.MethodsHyperfiltration was defined as a GFR≥135 ml/min/1.73m2, which is the median value used in the literature. A normal GFR was defined as a GFR between 90 and 135 ml/min/1.73m2. We obtained a baseline nuclear medicine GFR for a cohort of 74 consecutive first allogeneic SCT patients > 2 years of age at time of transplant. Outcomes assessed included AKI, defined as a doubling of creatinine in the first year of transplant, need for renal replacement therapy, and 1 year event free survival. In patients who had at least 2 years of follow up, the outcome of CKD was defined as a GFR<90 or GFR≥135 ml/min/1.73m2 at last follow up.ResultsThere was no association between hyperfiltration and transplant demographics (Table 1). 11 patients were excluded from analysis due to baseline GFR<90 ml/min/1.73m2. Median GFR of the 22 hyperfiltraters was 154 ml/min/1.73m2 (IQR 146, 170). Median GFR of the 41 patients with normal GFR was 115 ml/min/1.73m2 (IQR 107, 125). All 63 patients had 1 year follow up data; 37 patients had follow up data past 2 years (median 4.7 years). We found no association between baseline hyperfiltration and any of the outcomes (Table 1).ConclusionsPre-SCT GFR≥135 ml/min per 1.73m2 was not associated with AKI, 1 year event free survival, or CKD at a median follow up time of 4.7 years. Further research is needed to determine whether a different threshold for hyperfiltration would have prognostic value. Follow up to assess long term risk of CKD is also warranted in these patients. Glomerular hyperfiltration is defined as an abnormally high GFR. Consensus is lacking as to what GFR constitutes hyperfiltration, and its role as a risk factor for acute kidney injury (AKI) and chronic kidney disease (CKD) is poorly understood. It has been shown that decreased GFR prior to transplant is associated with subsequent AKI, but there are no studies looking at the effect of pre-transplant hyperfiltration in pediatric transplant patients. Determine whether pre-transplant hyperfiltration is a risk factor for renal morbidity and overall mortality in pediatric SCT patients. Hyperfiltration was defined as a GFR≥135 ml/min/1.73m2, which is the median value used in the literature. A normal GFR was defined as a GFR between 90 and 135 ml/min/1.73m2. We obtained a baseline nuclear medicine GFR for a cohort of 74 consecutive first allogeneic SCT patients > 2 years of age at time of transplant. Outcomes assessed included AKI, defined as a doubling of creatinine in the first year of transplant, need for renal replacement therapy, and 1 year event free survival. In patients who had at least 2 years of follow up, the outcome of CKD was defined as a GFR<90 or GFR≥135 ml/min/1.73m2 at last follow up. There was no association between hyperfiltration and transplant demographics (Table 1). 11 patients were excluded from analysis due to baseline GFR<90 ml/min/1.73m2. Median GFR of the 22 hyperfiltraters was 154 ml/min/1.73m2 (IQR 146, 170). Median GFR of the 41 patients with normal GFR was 115 ml/min/1.73m2 (IQR 107, 125). All 63 patients had 1 year follow up data; 37 patients had follow up data past 2 years (median 4.7 years). We found no association between baseline hyperfiltration and any of the outcomes (Table 1). Pre-SCT GFR≥135 ml/min per 1.73m2 was not associated with AKI, 1 year event free survival, or CKD at a median follow up time of 4.7 years. Further research is needed to determine whether a different threshold for hyperfiltration would have prognostic value. Follow up to assess long term risk of CKD is also warranted in these patients.