Cognitive Impairment in Kidney Disease

An increasing number of Veterans are anticipated to develop chronic kidney disease (CKD) and require hemodialysis (HD) treatments as the Veteran population ages. In 2003, approximately 290,000 US citizens were receiving HD and an estimated 19 million were affected by CKD. The annual growth rate is predicted to be 7% per year with 500,000 Americans receiving HD treatment by 2010. In 2005, approximately 2500 Veterans were receiving HD with growth expected to parallel that seen in the general population. Whereas Alzheimer's disease is the leading cause of dementia in the general population, growing evidence suggests that patients with advanced CKD experience cognitive deficits related to accelerated cerebrovascular disease. Patients with advanced CKD have been shown to have a high prevalence of sub-clinical cerebrovascular damage on imaging studies and a heavy burden of vascular risk factors such as diabetes, elevated cholesterol, and hypertension. Many of the cognitive deficits related to cerebrovascular disease may go unrecognized by routine measures of cognition. HD patients have increased number of hospitalizations, and several compliance issues ranging from congestive heart failure to dangerous electrolyte imbalances. Impaired cognition in this population is likely to have a significant impact on self-care and compliance with complex medical regimens. Currently, the severity and scope of cognitive impairment related to vascular disease is not well known in patients with advanced kidney disease. Additionally, the relationship between cognitive impairment and measures of self-care independence are not well known. Loss of independence and function secondary to impaired cognitive function is likely to be a significant problem for patients with advanced kidney disease. Early identification of functional impairment, particularly instrumental activities of daily living (IADL), will allow for rehabilitation intervention. Maintaining or improving functional independence through intensive rehabilitation could translate into better compliance and lower hospitalization rate among HD patients. Information obtained from this study is likely to heighten awareness of cognitive impairment and the functional consequences in Veterans with advanced kidney disease. Primary objectives are to determine:

1. The range of cognitive deficits with emphasis on domains affected by vascular disease in patients with advanced CKD and those receiving hemodialysis.
2. The associations between severity of cognitive impairment and severity of kidney disease.
3. The prevalence of impaired IADLs and the level of health-related quality of life (HRQOL) in patients with advanced CKD and those requiring hemodialysis.
4. The relationship or association of cognitive impairment with IADL and HRQOL.

Secondary objective is to determine:

1. The relationships among cerebral and carotid blood flow, carotid artery stiffness, and renal specific metabolic abnormalities with cognitive impairment.