Predictors of Longitudinal Changes in Neurocognitive Functioning in Pediatric Chronic Kidney Disease: Findings From the CKiD Study

OBJECTIVE The primary objective of this study is to examine changes in targeted neurocognitive functions over time and to determine what factors influence these changes. METHODS Participants included 827 cases with mild to moderate chronic kidney disease (CKD). Median chronological age was 11.5 years at study entry, 61% were male, and 39% of mothers had a high school education or less. Cognitive assessment included measures of intelligence, attention regulation, and executive functioning administered at study entry and every 2 years over a span of 8 years. Covariates at study entry included sociodemographic, CKD-related, and selected time-varying factors (eg, estimated glomerular filtration rate [eGFR] annual percent change). Longitudinal linear mixed models were used to examine a priori neurocognitive outcomes. RESULTS After adjustment for covariates, IQ and executive-function ratings increased slightly over time; however, an initial association was shown for greater change in eGFR contributing to significantly lower verbal IQ and full scale IQ over time (ie, ∼1/2 point per 5% decline in eGFR). After correction for multiple comparisons, abnormal birth history and the presence of seizures were associated with declines in IQ (∼1 to 7 points). CONCLUSIONS Findings from this study suggest relative stability in cognition over an 8-year period in children with mild to moderate CKD, although targeted CKD-related variables were significantly associated with lower IQ scores over time. In particular, abnormal birth history and seizures were associated with declines in cognitive functions over time, and clinical evaluation may be warranted when such conditions are present.