Lower levels of kidney function were associated with lower levels of cognitive functioning in CKD patients, particularly for tasks involving overall cognitive function, visuospatial scanning, motor speed, executive function, attention, and object naming.
Chart Explanation: Overall, cognitive function was worse with more severely reduced kidney function across all measures. The association of decreased cognitive function with reduced kidney function was statistically significant for overall cognitive function (M-MMSE); visuospatial scanning, motor speed, executive function, and attention (Trails A and B); and naming of visual objects (Boston Naming).
The Chronic Renal Insufficiency Cohort (CRIC) study is a cohort study of 3,612 individuals 21-74 years of age with CKD of varying severity, recruited from 13 sites across the United States in 2003-2007. CRIC was designed to study consequences of CKD with a particular focus on cardiovascular illness like myocardial infarction (heart attack) and stroke. As with all cohort studies, participants may not be representative of all those who live in the communities from which they are recruited.
Analyses for this measure were performed in 825 older (55+ years old) adults with CKD enrolled in the CRIC study. Cognitive tests including the Modified Mini-Mental State Examination (general cognitive battery), the Trail-Making Test Parts A and B (visuospatial scanning, motor speed, executive function, and attention), Category (verbal) Fluency (verbal production, semantic memory, and language), Buschke Selective Reminding Test (immediate and delayed verbal memory), and Boston Naming (naming of objects presented in pictures). Complete methods can be found in Yaffe et al. (2010).
|Description of Measure||Cognitive function among adults with CKD|
|Data Source||CRIC prospective observational cohort study (ancillary)|
|Type of Data Source||Private|
|Data Set||CRIC summarized data|
|Health Care System Data||No|
|Regional or National?||National|
|Demographic Group||Older adults (55-74 years old) with mild to severe CKD who are treated throughout 13 sites in 7 U.S. centers and enrolled in the CRIC main study|
|Numerator||— (mean score)|
|Denominator||Older adults with cognitive testing results from next scheduled visit|
|Definition of CKD||Estimated GFR of 20-60 (ages 45-64) and 20-50 (ages 65+) ml/min/1.73 m² (for entry into study)|
|Glomerular filtration rate||Estimated, MDRD Study equation|
|Primary Data Source Indicator||Cognitive test scores|
|Primary Indicator Method of Measurement||Investigator-administered cognitive testing as part of CRIC study visit|
|Secondary (1) Variable||Kidney function|
|Secondary (1) Indicator Method of Measurement||Estimated eGFR|
|Frequency of Measurement (Primary)||Once (baseline or next visit)|
|U.S. Region Covered by Primary Variable||Seven urban centers throughout the United States (Baltimore, MD; Philadelphia, PA; Cleveland, OH; Detroit, MI; Chicago, IL; New Orleans, LA; Oakland, CA)|
|Period Currently Available||2003–2007|
|Pending Data||None for baseline/first visit; further visits scheduled|
|Additional Data Items of Interest||Stratification variables of interest (age, gender, race/ethnicity), diabetes, labs|
|Limitations of Indicator||Cross-sectional analyses and possibly “healthy cohort” effect|
|Analytical Considerations||Data summarized by CRIC investigators (see Yaffe et al.); as with all cohort studies, selection bias and possible confounding|
References and Sources:
Yaffe K, Ackerson L, Kurella Tamura M, et al. Chronic Renal Insufficiency Cohort Investigators. Chronic kidney disease and cognitive function in older adults: findings from the chronic renal insufficiency cohort cognitive study. J Am Geriatr Soc. 2010;58(2):338-45.