Measurement and estimation of glomerular filtration rate in children with neurogenic bladder: A prospective study

Utility of Cystatin C-based Equation for the Estimation of Glomerular Filtration Rate in a Pediatric Population

BACKGROUND

The accurate assessment of kidney function is vital for the early detection of kidney damage. The estimated glomerular filtration rate GFR (eGFR) from serum cystatin C (CysC) and creatinine-based equations are commonly used in clinical practice as an alternative to the invasive measured glomerular filtration rate (mGFR), which is the usually accepted overall best index of kidney function in health and disease. Recently the CKiD under 25 (CkiD U25) equations have been shown to perform well in children and young adults with chronic kidney disease (CKD). In this focused report, we evaluated the performance of the CkiD U25 equations alongside 3 non-race-corrected (NRC) eGFR equations commonly used in pediatrics in our cohort.

METHODS

mGFR measured following the intravenous injection of tracer Tc-99mDTPA was retrospectively compared with eGFR from these equations in 57 patients (6 months to 22 years) from different races/ethnicities. Ordinary least squares regression analyses were used to assess correlation between the mGFRs and eGFRs.

RESULTS

The average mGFR for this cohort was 84.1 mL/min/1.73 m2. The NRC creatinine equations overestimated eGFR across all groups, with the lowest bias for CKiD U25-creatinine (22.59 mL/min/1.73 m2). The best correlations to mGFR, P30, and lowest biases were the CKiD U25-CysC (0.6281, 80.7%, 3.72 mL/min/1.73 m2) and Schwartz CysC (0.6372, 77.2%, -4.68 mL/min/1.73 m2).

CONCLUSIONS

Overall, both CKiD U25-CysC and Schwartz CysC provide a good estimation of mGFR with the CKiD U25-CysC having the overall best performance compared to mGFR in our study.

Challenges of pediatric pharmacotherapy: A narrative review of pharmacokinetics, pharmacodynamics, and pharmacogenetics

PURPOSE

Personalized pharmacotherapy, including for the pediatric population, provides optimal treatment and has emerged as a major trend owing to advanced drug therapeutics and diversified drug selection. However, it is essential to understand the growth and developmental characteristics of this population to provide appropriate drug therapy. In recent years, clinical pharmacogenetics has accumulated knowledge in pediatric pharmacotherapy, and guidelines from professional organizations, such as the Clinical Pharmacogenetics Implementation Consortium, can be consulted to determine the efficacy of specific drugs and the risk of adverse effects. However, the existence of a large knowledge gap hinders the use of these findings in clinical practice.

METHODS

We provide a narrative review of the knowledge gaps in pharmacokinetics (PK) and pharmacodynamics (PD) in the pediatric population, focusing on the differences from the perspective of growth and developmental characteristics. In addition, we explored PK/PD in relation to pediatric clinical pharmacogenetics.

RESULTS

The lack of direct and indirect biomarkers for more accurate assessment of the effects of drug administration limits the current knowledge of PD. In addition, incorporating pharmacogenetic insights as pivotal covariates is indispensable in this comprehensive synthesis for precision therapy; therefore, we have provided recommendations regarding the current status and challenges of personalized pediatric pharmacotherapy. The integration of clinical pharmacogenetics with the health care system and institution of educational programs for health care providers is necessary for its safe and effective implementation. A comprehensive understanding of the physiological and genetic complexities of the pediatric population will facilitate the development of effective and personalized pharmacotherapeutic strategies.

The urological evaluation and management of neurogenic bladder in children and adolescents-what every pediatric nephrologist needs to know

Neurogenic bladder (NGB) is an encompassing term that includes multiple causes of bladder dysfunction linked to a congenital or acquired neurological condition that adversely impacts the innervation of the lower urinary tract. Multiple static or progressive conditions can be associated with NGB in pediatric and adolescent patients. Currently, spinal dysraphism (i.e., spina bifida) is one of the most common etiologies, which occurs in 3-4 per 10,000 live births in developed nations. Abnormal bladder dynamics can lead to kidney damage secondary to high pressures or recurrent infections, as well as urinary incontinence. The current management paradigm centers on a proactive approach to preserving kidney function and achieving continence through behavioral, pharmacological, and surgical means. This educational review highlights the key components of urological management to maximize collaboration with pediatric nephrologists.

Estimating the Glomerular Filtration Rate in Pediatric Patients With Neurogenic Bladder: A Comparison Between Creatinine- and Cystatin C-Equations

Background and objective Patients with neurogenic bladder (NB) are at a higher risk of developing chronic kidney disease (CKD). Due to their lower muscle mass, the estimated glomerular filtration rate (eGFR) based on creatinine (Cr) may be overestimated and delay the diagnosis of renal failure. This study compared eGFR calculated with different equations based on Cr and/or cystatin C (CysC) in children with NB, and the differences between patients with lower muscle mass (underdeveloped lower limbs) and those with independent gait (less muscle depletion). Methods We calculated the eGFR in pediatric patients with NB and CKD stages 1 and 2 by using the following equations: Chronic Kidney Disease in Children equation for serum creatinine (CKiD-Cr), CKiD-CysC, CKiD combined-Cr/CysC, Zappitelli-CysC, and Zappitelli combined-Cr/CysC. Results We evaluated a total of 47 patients, 74.5% with CKD stage 1, with a median age of 14.1 years. Of these participants, 59.6% had lipo/myelomeningocele. The CKiD-Cr and CysC-based equations led to significantly lower calculated eGFR ​​(p<0.05), specifically CKiD-CysC (p<0.001), Zappitelli-CysC (p<0.001), CKiD-Cr/CysC (p<0.001), and Zappitelli combined-Cr/CysC (p<0.05). When CKiD-CysC was used, 68% of the patients moved to a more advanced CKD stage. In patients without independent gait, with lower muscle mass (55.3%), the median eGFR calculated using the CKiD-Cr and CKiD combined-Cr/CysC equations was significantly higher (p<0.05). However, there were no differences between the two groups when using the other CysC-based equations. Conclusion In patients with NB and poor muscle mass, the CKiD-Cr equation may overestimate renal function. CysC-based equations seem more reliable in these patients, especially in those with greater muscular atrophy.