Children With CKD Have Lower IQs
One possible explanation is that increased plasma levels of uremic solutes resulting from kidney disease may impair synaptic development.
Children with chronic kidney disease (CKD) may have more intellectual and academic difficulties than other children, according to new research findings.
Kerry Chen, MBBS, of The Children's Hospital at Westmead in Sydney, Australia, and the University of Sydney's Centre for Kidney Research, and colleagues performed a systematic review of 34 observational studies including 3086 children (younger than 21 years) residing in 9 countries. Of the children with CKD, 86% had mild-to-moderate stage disease, 4.7% received dialysis, and 9.8% underwent kidney transplants. Eighteen studies were used for meta-analyses. The overall risk of bias among the studies was high, according to the investigators.
According to results published online ahead of print in the Clinical Journal of the American Society of Nephrology, the global cognition of children with CKD was low-average as assessed by the full-scale intelligence quotient (FSIQ). The mean difference in FSIQ was 10.5 points lower for children and adolescents with CKD compared with the general population. By subgroup, scores were 9.39, 11.2, and 16.2 points lower for kids with pre-dialysis CKD, those with kidney transplants, and those on dialysis, respectively. Dialysis patients scored 11.2 and 10.1 FSIQ points lower than children with mild-to-moderate CKD or kidney transplants, respectively. With regard to executive function and memory (verbal and visual), pediatric CKD patients overall scored lower than the general population.
Academically, CKD patients scored 15.7 to 1.22 points lower in mathematics, 9.04 to 0.17 points lower in reading, and 14.2 to 2.53 points lower in spelling. Children with CKD had difficulty in holding information and shifting from 1 stimulus to another, the authors explained. Despite fewer cognitive skills, students with CKD could regulate their behavior.
“Clinically, scores at least one SD [standard deviation] lower in overall intelligence and domain-specific cognitive domains place children at increased risk of poor academic performance at school, reduced quality of life and poor mental health with potential implications for vocational attainment and financial independence as they transition into adulthood,” Dr Chen and his collaborators warned.
Several possible mechanisms might underlie the connection between CKD and intellectual impairment. “Firstly, increased plasma levels of uremic solutes arising from kidney disease may impair synaptic development," Dr Chen explained in a news release from the University of Sydney. “Dialysis may also lead to cognitive impairment through rapid changes in blood pressure.”
Further, the pathologic effects associated with end-stage renal disease, such as anemia, hypertension, and malnutrition, may reduce cognitive function among children on dialysis compared with other CKD stages.
He noted that treatments for CKD may compromise academic achievement. The frequency of sleep disturbances in kids with CKD may result in poor concentration, excessive daytime sleepiness, and lower academic performance.
In addition, Dr Chen observed, “the interactions of complex medication routines and strict dialysis cycles may decrease attentional control, working memory, and executive function-cognitive domains that are important to children's ability to acquire, understand, and retain information in social and educational environments.”
Lastly, he said, ongoing dialysis sessions and recovery from transplant surgeries may decrease the amount and regularity of time spent in the classroom, “with chronic absenteeism potentially preceding loss of interest, withdrawal, and poor school progression.”
In an accompanying editorial, Lori M. Hartwell, president of Renal Support Network in Glendale, California, and a former pediatric CKD patient, agreed: “This is a valuable review of several existing studies; a serious reminder that children and adolescents with chronic kidney disease face medical, psychological, and social barriers to learning; and a clear indication that interventions designed to be responsive to patient needs are necessary.”
Chen K, et al "Neurocognitive and educational outcomes in children and adolescents with chronic kidney disease: A systematic review and meta-analysis." Clin J Am Soc Nephrol. DOI:10.2215/CJN.09650917.
Hartwell LM "Responsive designed interventions are needed to support positive outcomes of children and adolescents with chronic kidney disease" Clin J Am Soc Nephrol. DOI:10.2215/CJN.09650917.
Kids with chronic kidney disease have lower IQs and poorer educational outcomes. University of Sydney; February 22, 2018. [news release]