Cognitive Dysfunction and Gait Abnormalities in CKD

Cognitive impairment is a major cause of morbidity in CKD. We hypothesized that gait abnormalities share a common pathogenesis with cognitive dysfunction in CKD, and therefore would be associated with impaired cognitive function in older adults with CKD, and focused on a recently defined gait phenotype linked with CKD.

Gait assessments and neuropsychological testing were performed in 312 nondisabled, community-dwelling older adults (aged ≥65 years). A subset (n=115) underwent magnetic resonance imaging. The primary cognitive outcome was the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) total scale score. Associations with cognitive function were tested using multivariable linear regression and nearest-neighbor matching. The risk of developing mild cognitive impairment syndrome was assessed using Cox proportional hazards models.

Lower eGFR was associated with lower RBANS score only among participants with the gait phenotype (P for interaction =0.04). Compared with participants with neither CKD nor the gait phenotype, adjusted RBANS scores were 5.4 points (95% confidence interval, 1.8 to 9.1) lower among participants with both, who demonstrated poorer immediate memory, visuospatial ability, delayed memory, and executive function. In a matched analysis limited to participants with CKD, the gait phenotype was similarly associated with lower RBANS scores (-6.9; 95% confidence interval, -12.2 to -1.5). Neuroimaging identified a pattern of gray matter atrophy common to both CKD and the gait phenotype involving brain regions linked with cognition. The gait phenotype was associated with higher risk of mild cognitive impairment (hazard ratio, 3.91; 95% confidence interval, 1.46 to 10.44) independent of eGFR.

The gait phenotype was associated with poorer function in a number of cognitive domains among older adults with CKD, and was associated with incident mild cognitive impairment independent of eGFR. CKD and the gait phenotype were associated with a shared pattern of gray matter atrophy.