Chronic kidney disease (CKD) and diabetes were associated with a higher risk of neurocognitive decline, but kidney disease stage did not appear to affect risk.
Elderly patients with chronic kidney disease (CKD) and diabetes appear to have roughly double the risk of developing neurocognitive disorders compared with healthy controls, according to a new study.
CKD is commonly associated with comorbid conditions like diabetes, cardiovascular disease, and hypertension, which have a significant impact on mortality in this patient group. However, the authors of this new study say there is reason to believe CKD also affects other parts of the body, such as the brain.
“Given that CKD is a systemic condition, its relation with neurological function warrants closer investigation, especially in view of the increase in the prevalence of CKD in aging populations,” Hobson the authors wrote in BMJ Open.
They said it is important to consider how the brain and CKD interact, because vascular and hemodynamic changes can be associated with neurodegenerative function. In addition, they said neurodegenerative changes are often overlooked in the clinical management of CKD.
Previous research has suggested that nearly half of patients with CKD and diabetes have some level of neurocognitive impairment, ranging from mild impairment to dementia. Yet, the study authors said the existing literature could be overinterpreting the risk of dementia, since it included patients who had cognitive impairment at baseline.
In hopes of getting around that concern, the investigators decided to compare rates of neurocognitive decline among 2 cohorts of age- and sex-matched subjects who had normal cognitive function at baseline. One cohort consisted of 92 patients with CKD and diabetes, and the other cohort was made up of 143 healthy controls. The CKD group had a mean age of 75.8, and the control group had a mean age of 74.4.
Patients underwent cognitive function assessments at baseline and after approximately 36 months.
The data showed that 25 of 92 patients (27.2%) in the CKD group neurocognitive disorders by follow-up. In the control group, just 20 of 143 patients (13.9%) developed neurocognitive disorders.
When adjusted for age and sex, the investigators found patients with CKD had double the risk of a neurocognitive disorder. Notably, they found different predictors of neurocognitive decline between the 2 groups. In patients with CKD, memory, fluency, and executive function impairment correlated with the development of neurocognitive disorders.
“Whereas, in the control cohort, memory and visuospatial impairments were revealed as the strongest predictors, suggesting possible differing pathological and etiological pathways in the mild cognitive impairment and the dementia type in CKD,” Hobson and colleagues wrote.
Cognitive function did not appear to correlate with CKD stage, they found.
“Although our results are not supportive of an association with the stage of CKD and [neurocognitive disorder], they do nevertheless suggest that cognitive impairment is common in CKD, which needs to be carefully assessed and incorporated in the overall management of the condition,” the authors wrote.
They concluded that the pattern of cognitive impairment symptoms in these patients suggests clinicians could identify patients at risk of neurocognitive disorders without the need to refer such patients to specialists.
“This is because they are measurable relatively quickly in normal clinical practice and require modest upskilling among the clinical teams in their application, scoring, and interpretation,” they wrote.
Hobson P, Kumwenda M, Shrikanth S, Nair H, Wong S. Risk and incidence of cognitive impairment in patients with chronic kidney disease and diabetes: the results from a longitudinal study in a community cohort of patients and an age and gender-matched control cohort in North Wales, UK. BMJ Open. Published online March 11, 2022. doi:10.1136/bmjopen-2021-053008