Kidney Function and Cognitive Impairment in US Adults: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study
Received 8 August 2007; accepted 12 May 2008. published online 01 July 2008.
Refers to article:
The Cognition–Kidney Disease Connection: Lessons From Population-Based Studies in the United States
Daniel E. Weiner
American Journal of Kidney Diseases
August 2008 (Vol. 52, Issue 2, Pages 201-204) Full Text |
Full-Text PDF (131 KB)
Background
The association between kidney function and cognitive impairment has not been assessed in a national sample with a wide spectrum of kidney disease severity.
Study Design
Cross-sectional.
Setting & Participants
23,405 participants (mean age, 64.9 ± 9.6 years) with baseline measurements of creatinine and cognitive function participating in the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, a study of stroke risk factors in a large national sample.
Predictor
Estimated glomerular filtration rate (eGFR).
Outcome
Cognitive impairment.
Measurements
Chronic kidney disease (CKD) was defined as eGFR less than 60 mL/min/1.73 m2. Kidney function was analyzed in 10-mL/min/1.73 m2 increments in those with CKD, and in exploratory analyses, across the range of kidney function. Cognitive function was assessed using the 6-Item Screener, and participants with a score of 4 or less were considered to have cognitive impairment.
Results
CKD was associated with an increased prevalence of cognitive impairment independent of confounding factors (odds ratio, 1.23; 95% confidence interval, 1.06 to 1.43). In patients with CKD, each 10-mL/min/1.73 m2 decrease in eGFR less than 60 mL/min/1.73 m2 was associated with an 11% increased prevalence of impairment (odds ratio, 1.11; 95% confidence interval, 1.04 to 1.19). Exploratory analyses showed a nonlinear association between eGFR and prevalence of cognitive impairment, with a significant increased prevalence of impairment in those with eGFR less than 50 and 100 mL/min/1.73 m2 or greater.
Limitations
Longitudinal measures of cognitive function were not available.
Conclusions
In US adults, lower levels of kidney function are associated with an increased prevalence of cognitive impairment. The prevalence of impairment appears to increase early in the course of kidney disease; therefore, screening for impairment should be considered in all adults with CKD.
ABSTRACT