Presentation Authors: David Chu*, Lauren Balmert, Cameron Arkin, Theresa Meyer, Ilina Rosoklija, Diana Bowen, Kavita Hodgkins, Earl Cheng, Tamara Isakova, Elizabeth Yerkes, Chicago, IL
Introduction: Emerging adults with spina bifida (SB) may face inaccurate kidney function assessment as they bridge the age gap between pediatric and adult equations for estimated glomerular filtration rate (eGFR). We examined the variability of eGFR in emerging adults with SB by comparing multiple equations across the transitional age period, hypothesizing that creatinine (Cr)-based equations show greater variability than cystatin-C (CysC)- or combo-based equations.
Methods: A retrospective cohort study was performed from 2002-2017 at a multi-disciplinary SB clinic. Emerging adults were defined as patients ages 18-28 years old. Four pediatric, 3 adult, and 3 averaged eGFR equations were considered. Cross-sectional variability using the most recent eGFR data was assessed using coefficients of variation (CV), chronic kidney disease (CKD) stage classification, and pairwise percent relative difference between analogous pediatric and adult equations based on included lab values. Longitudinal changes in eGFR over time were compared across equations using a covariance pattern model accounting for repeated measures.
Results: 75 patients with SB (median age 21.8 years; 55% female; 83% with myelomeningocele) were included in cross-sectional analyses. CVs ranged from 14.5 (Zappitelli equation) to 34.0 (bedside Schwartz equation; Table 1). Pediatric equations had lower median eGFRs by 18-21% and worse CKD stage classification than analogous adult equations (Table 2). In longitudinal analyses (median follow-up of 22 months), all equations conferred negative eGFR changes over time (range -1.9 to -4.3 mL/min/1.73m2 per year) that were not significantly different.
Conclusions: In emerging adults with SB, pediatric equations uniformly had lower median eGFRs compared to analogous adult equations and worse CKD stage classification, but eGFR changes over time were not significantly different. The same eGFR equation should be used for serial kidney function monitoring in emerging adults with SB who transition care from pediatric to adult services.