Cognitive Impairment in the Aging Dialysis and Chronic Kidney Disease Populations: An Occult Burden
2008; Elsevier BV; Volume: 15; Issue: 2 Linguagem: Inglês
10.1053/j.ackd.2008.01.010
ISSN1548-5609
Autores Tópico(s)Neurological Complications and Syndromes
ResumoThe high burden of cognitive impairment in hemodialysis and chronic kidney disease (CKD) patients has only recently become recognized. Up to 70% of hemodialysis patients aged 55 years and older have moderate to severe chronic cognitive impairment, yet it is largely undiagnosed. Recent studies describe the strong graded relation between estimated glomerular filtration rate and cognitive function in CKD patients. The process of conventional hemodialysis may induce recurrent episodes of acute cerebral ischemia, which, in turn, may contribute to acute decline in cognitive function during dialysis. Thus, the worst time to communicate with dialysis patients may be during the hemodialysis session. Both symptomatic and occult, subclinical ischemic cerebrovascular disease appears to play a large role in a proposed model of accelerated vascular cognitive impairment in these populations. Severe cognitive impairment or dementia among hemodialysis patients is associated with an approximately 2-fold increased risk of both mortality and dialysis withdrawal. Predialysis cognitive screening and adding dementia to the list of comorbidities on Form 2728 would provide critical information regarding the benefit versus risks of receiving dialysis. It could also improve quality of care and outcomes by raising clinicians' awareness of the potential effects of cognitive impairment on medication, fluid, and dietary compliance and the ability to make advance directive decisions among dialysis patients. Although much remains to be learned regarding the pathophysiology of cognitive impairment in kidney disease, the public health implications of this substantial burden are immediate. The high burden of cognitive impairment in hemodialysis and chronic kidney disease (CKD) patients has only recently become recognized. Up to 70% of hemodialysis patients aged 55 years and older have moderate to severe chronic cognitive impairment, yet it is largely undiagnosed. Recent studies describe the strong graded relation between estimated glomerular filtration rate and cognitive function in CKD patients. The process of conventional hemodialysis may induce recurrent episodes of acute cerebral ischemia, which, in turn, may contribute to acute decline in cognitive function during dialysis. Thus, the worst time to communicate with dialysis patients may be during the hemodialysis session. Both symptomatic and occult, subclinical ischemic cerebrovascular disease appears to play a large role in a proposed model of accelerated vascular cognitive impairment in these populations. Severe cognitive impairment or dementia among hemodialysis patients is associated with an approximately 2-fold increased risk of both mortality and dialysis withdrawal. Predialysis cognitive screening and adding dementia to the list of comorbidities on Form 2728 would provide critical information regarding the benefit versus risks of receiving dialysis. It could also improve quality of care and outcomes by raising clinicians' awareness of the potential effects of cognitive impairment on medication, fluid, and dietary compliance and the ability to make advance directive decisions among dialysis patients. Although much remains to be learned regarding the pathophysiology of cognitive impairment in kidney disease, the public health implications of this substantial burden are immediate. The heavy burden of cognitive impairment in hemodialysis and chronic kidney disease (CKD) patients has only recently become recognized. This review summarizes the state of knowledge regarding the epidemiology and pathophysiology of acute and chronic cognitive impairment in these populations. The intent is to provide an update to the excellent summary of the epidemiology of cognitive function in dialysis patients by Pereira et al1Pereira A.A. Weiner D.E. Scott T. et al.Cognitive function in dialysis patients.Am J Kidney Dis. 2005; 45: 448-462Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar in 2005. Although much remains to be learned regarding the multiple causes of cognitive impairment in these populations, the health policy implications of this substantial burden are immediate. For the purposes of this review, severe cognitive impairment will be considered as approximately equivalent to dementia, which per Diagnostic Manual of Mental Disorders, Fourth Edition criteria is defined as chronic cognitive impairment in 2 or more cognitive domains that substantially affects daily function, represents a decline in premorbid function, and is not caused by concomitant acute delirium.2Murray A.M. Tupper D.E. Knopman D.S. et al.Cognitive impairment in hemodialysis patients is common.Neurology. 2006; 67: 216-223Crossref PubMed Scopus (493) Google Scholar, 3American Psychiatric Association: Diagnostic and statistical manual of mental disorders (ed 4). American Psychiatric Association, Washington, DC1994Google Scholar Early studies among small samples of hemodialysis patients reported moderate rates of cognitive impairment across multiple cognitive domains but often excluded older patients or those with stroke or severe comorbid conditions.4Nissenson A.R. Marsh J.T. Brown W.S. et al.Central nervous system function in dialysis patients: A practical approach.Semin Dial. 1991; 4: 115-123Crossref Scopus (24) Google Scholar, 5Gilli P. De Bastiani P. Cognitive function and regular dialysis treatment.Clin Nephrol. 1983; 19: 188-192PubMed Google Scholar, 6Pliskin N.H. Yurk H.M. Ho L.T. et al.Neurocognitive function in chronic hemodialysis patients.Kidney Int. 1996; 49: 1435-1440Crossref PubMed Scopus (85) Google Scholar, 7Ratner D.P. Adams K.M. Levin N.W. et al.Effects of hemodialysis on the cognitive and sensory-motor functioning of the adult chronic hemodialysis patient.J Behav Med. 1983; 6: 291-311Crossref PubMed Scopus (37) Google Scholar, 8Ryan J.J. Souheaver G.T. DeWolfe A.S. Intellectual deficit in chronic renal failure. A comparison with neurological and medical-psychiatric patients.J Nerv Ment Dis. 1980; 168: 763-767Crossref PubMed Scopus (10) Google Scholar One 1997 study using the relatively insensitive Mini-Mental State Examination found that 30% of 336 hemodialysis patients aged 23 to 93 years had mild to severe cognitive impairment, using very conservative cut points.9Sehgal A.R. Grey S.F. DeOreo P.B. et al.Prevalence, recognition, and implications of mental impairment among hemodialysis patients.Am J Kidney Dis. 1997; 30: 41-49Abstract Full Text PDF PubMed Scopus (209) Google Scholar Two recent studies describe the high prevalence of cognitive impairment in CKD and hemodialysis patients.2Murray A.M. Tupper D.E. Knopman D.S. et al.Cognitive impairment in hemodialysis patients is common.Neurology. 2006; 67: 216-223Crossref PubMed Scopus (493) Google Scholar, 10Kurella M. Chertow G.M. Luan J. et al.Cognitive impairment in chronic kidney disease.J Am Geriatr Soc. 2004; 52: 1863-1869Crossref PubMed Scopus (343) Google Scholar In a study of CKD and hemodialysis patients by Kurella et al,10Kurella M. Chertow G.M. Luan J. et al.Cognitive impairment in chronic kidney disease.J Am Geriatr Soc. 2004; 52: 1863-1869Crossref PubMed Scopus (343) Google Scholar among 80 hemodialysis patients (mean age, 61.2 years), 38% had severe impairment in executive function and 33% severe memory impairment. We found very similar results in our recent study of 338 hemodialysis subjects. Using a detailed 45-minute neuropsychological battery, 37% of subjects had severe, 36% moderate, and 14% mild cognitive impairment; only 13% had normal cognitive function. Hemodialysis patients were more than 3 times as likely to have severe cognitive impairment than a comparison group of non-CKD patients. However, clinical awareness of the diagnosis was poor; cognitive impairment was only documented by medical record in 2.9% of the cohort. Among stage 3 to 4 CKD patients in the study by Kurella et al,10Kurella M. Chertow G.M. Luan J. et al.Cognitive impairment in chronic kidney disease.J Am Geriatr Soc. 2004; 52: 1863-1869Crossref PubMed Scopus (343) Google Scholar 23% had severely impaired executive function and 28% scored poorly on delayed memory. Multiple studies report a cross-sectional, graded relation between estimated glomerular filtration rate (eGFR) level and cognitive function.10Kurella M. Chertow G.M. Luan J. et al.Cognitive impairment in chronic kidney disease.J Am Geriatr Soc. 2004; 52: 1863-1869Crossref PubMed Scopus (343) Google Scholar, 11Kurella M. Yaffe K. Shlipak M.G. et al.Chronic kidney disease and cognitive impairment in menopausal women.Am J Kidney Dis. 2005; 45: 66-76Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar, 12Hailpern S.M. Melamed M.L. Cohen H.W. et al.Moderate chronic kidney disease and cognitive function in adults 20 to 59 years of age: Third National Health and Nutrition Examination Survey (NHANES III).J Am Soc Nephrol. 2007; 18: 2205-2213Crossref PubMed Scopus (151) Google Scholar In the Heart, Estrogen/Progesterone Study among menopausal women, each 10 mL/min/1.73 m2 decrement in eGFR corresponded to an approximately 15% to 25% increase in risk for cognitive dysfunction among individual cognitive domains.11Kurella M. Yaffe K. Shlipak M.G. et al.Chronic kidney disease and cognitive impairment in menopausal women.Am J Kidney Dis. 2005; 45: 66-76Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar There is also evidence for a longitudinal relation between baseline eGFR and cognitive decline. The Health and Aging Body Composition Study, using the Modified Mini-Mental State Examination, showed a significant graded risk for cognitive decline or dementia with CKD at baseline. For eGFR 45 to 59 mL/min per 1.73 m2, the AOR for cognitive decline was 1.32 compared with 2.43 for an eGFR 1.5 mg/dL in men and >1.3 mg/dL in women) was associated with a 37% increased risk of incident dementia over 6 years of follow-up among the 84% of subjects who reported good-excellent health.13Seliger S.L. Siscovick D.S. Stehman-Breen C.O. et al.Moderate renal impairment and risk of dementia among older adults: The Cardiovascular Health Cognition Study.J Am Soc Nephrol. 2004; 15: 1904-1911Crossref PubMed Scopus (277) Google Scholar Shared cardiovascular risk factors, however, may explain some of the association between severity of CKD and burden of cognitive impairment and do not prove cause and effect. According to the 2006 USRDS annual data report using Medicare claims data, the prevalence of dementia is slightly higher in the CKD cohort than the hemodialysis cohort, at 7.6% compared with 7%, respectively. It increases with age to 16.8% among those 85 years and older in the CKD cohort compared with 11.0% in the hemodialysis cohort.14United States Renal Data System: USRDS 2006 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2006Google Scholar Although more studies of the prevalence of cognitive impairment in these patient populations are needed, several suggest it is largely undetected by clinicians. In the study by Sehgal et al9Sehgal A.R. Grey S.F. DeOreo P.B. et al.Prevalence, recognition, and implications of mental impairment among hemodialysis patients.Am J Kidney Dis. 1997; 30: 41-49Abstract Full Text PDF PubMed Scopus (209) Google Scholar of 336 hemodialysis patients, only 15% of the cognitively impaired patients (Mini-Mental State Examination <24) had a medical record diagnosis of cognitive problems. Compared to the 7% USRDS rate of dementia, the prevalence of severe cognitive impairment in our primary collection study was 5 times greater, at 37%, and almost identical in the study by Kurella et al.15United States Renal Data System: USRDS 2005 Annual Data Report: Atlas of End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2005Google Scholar Our study cohort was representative of the USRDS cohort, except there were fewer nonwhites (47.6% in the USRDS v 18.7% in our cohort); because severe cognitive impairment was more common in the nonwhites, the prevalence may actually be higher. In the Dialysis Outcomes and Practice Patterns Study (DOPPS), only 4% of the hemodialysis population carried a medical record diagnosis of dementia.16Kurella M. Mapes D.L. Port F.K. et al.Correlates and outcomes of dementia among dialysis patients: The Dialysis Outcomes and Practice Patterns Study.Nephrol Dial Transplant. 2006; 21: 2543-2548Crossref PubMed Scopus (187) Google Scholar Thus, many cases may go unrecognized, raising the specter of a massive occult burden of cognitive impairment in CKD and hemodialysis patients.16Kurella M. Mapes D.L. Port F.K. et al.Correlates and outcomes of dementia among dialysis patients: The Dialysis Outcomes and Practice Patterns Study.Nephrol Dial Transplant. 2006; 21: 2543-2548Crossref PubMed Scopus (187) Google Scholar In community-based studies among the general population, older age, female gender, low education, race and ethnicity, diabetes, hypertension, lipids, stroke, anemia, history of head trauma, midlife obesity, inflammatory factors, the APOE-4 allele, and other genetic markers have been identified as risk factors for Alzheimer's disease or vascular cognitive impairment.17Hendrie H.C. Murrell J. Gao S. et al.International studies in dementia with particular emphasis on populations of African origin.Alzheimer Dis Assoc Disord. 2006; 20: S42-S46Crossref PubMed Scopus (41) Google Scholar, 18Posner H.B. Tang M.X. Luchsinger J. et al.The relationship of hypertension in the elderly to AD, vascular dementia, and cognitive function.Neurology. 2002; 58: 1175-1181Crossref PubMed Scopus (271) Google Scholar, 19Knopman D. Boland L.L. Mosley T. et al.Cardiovascular risk factors and cognitive decline in middle-aged adults.Neurology. 2001; 56: 42-48Crossref PubMed Scopus (731) Google Scholar, 20Arvanitakis Z. Wilson R.S. Bienias J.L. et al.Diabetes mellitus and risk of Alzheimer disease and decline in cognitive function.Arch Neurol. 2004; 61: 661-666Crossref PubMed Scopus (976) Google Scholar, 21Solomon A, Kareholt I, Ngandu T, et al: Serum total cholesterol, statins and cognition in non-demented elderly. Neurobiol Aging, in pressGoogle Scholar, 22Barberger-Gateau P. Raffaitin C. Letenneur L. et al.Dietary patterns and risk of dementia: The three-city cohort study.Neurology. 2007; 69: 1921-1930Crossref PubMed Scopus (559) Google Scholar, 23Qiu C. De Ronchi D. Fratiglioni L. The epidemiology of the dementias: An update.Curr Opin Psychiatry. 2007; 20: 380-385Crossref PubMed Scopus (342) Google Scholar Dietary intake (fruits, vegetables, Omega 3's, Mediterranean diet) and physical activity appear to be protective, and hormone replacement therapy and homocysteine are still controversial; there is also an interactive effect between some risk factors and the APOE-4 allele.24Gorelick P.B. Risk factors for vascular dementia and Alzheimer disease.Stroke. 2004; 35: 2620-2622Crossref PubMed Scopus (283) Google Scholar Hemodialysis and CKD populations share most of these same risk factors for cognitive impairment. However, in contrast to the general population, the roles of aging and nonvascular factors are overshadowed by stroke and the high prevalence of cardiovascular risk factors.18Posner H.B. Tang M.X. Luchsinger J. et al.The relationship of hypertension in the elderly to AD, vascular dementia, and cognitive function.Neurology. 2002; 58: 1175-1181Crossref PubMed Scopus (271) Google Scholar, 19Knopman D. Boland L.L. Mosley T. et al.Cardiovascular risk factors and cognitive decline in middle-aged adults.Neurology. 2001; 56: 42-48Crossref PubMed Scopus (731) Google Scholar, 20Arvanitakis Z. Wilson R.S. Bienias J.L. et al.Diabetes mellitus and risk of Alzheimer disease and decline in cognitive function.Arch Neurol. 2004; 61: 661-666Crossref PubMed Scopus (976) Google Scholar In addition, the contributions of factors secondary to kidney failure such as uremia, anemia, metabolic disturbances, and hemodynamic instability during dialysis are still to be defined.4Nissenson A.R. Marsh J.T. Brown W.S. et al.Central nervous system function in dialysis patients: A practical approach.Semin Dial. 1991; 4: 115-123Crossref Scopus (24) Google Scholar, 25Murray A.M. Pederson S.L. Tupper D.E. et al.Acute variation in cognitive function in hemodialysis patients: A cohort study with repeated measures.Am J Kidney Dis. 2007; 50: 270-278Abstract Full Text Full Text PDF PubMed Scopus (94) Google Scholar In the Health ABC study, CKD accounted for approximately 10%of the cognitive impairment risk that was unexplained by demographic factors and comorbidities.26Kurella M. Chertow G.M. Fried L.F. et al.Chronic kidney disease and cognitive impairment in the elderly: The health, aging, and body composition study.J Am Soc Nephrol. 2005; 16: 2127-2133Crossref PubMed Scopus (351) Google Scholar In the DOPPS, age, race, stroke, diabetes, low education, anemia, and measures of malnutrition were independently associated with dementia.16Kurella M. Mapes D.L. Port F.K. et al.Correlates and outcomes of dementia among dialysis patients: The Dialysis Outcomes and Practice Patterns Study.Nephrol Dial Transplant. 2006; 21: 2543-2548Crossref PubMed Scopus (187) Google Scholar Similar measurable risk factors have been identified in analyses in the USRDS CKD and hemodialysis populations.14United States Renal Data System: USRDS 2006 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2006Google Scholar Stroke, low education, and an equilibrated Kt/V ≥1.2 were associated with severe cognitive impairment in our study of 338 hemodialysis patients. Most hemodialysis patients are vasculopaths, with high rates of hypertension (80%), diabetes (60%),14United States Renal Data System: USRDS 2006 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2006Google Scholar markedly elevated levels of inflammatory markers and homocysteine,27Seshadri S. Beiser A. Selhub J. et al.Plasma homocysteine as a risk factor for dementia and Alzheimer's disease.N Engl J Med. 2002; 346: 476-483Crossref PubMed Scopus (2811) Google Scholar vascular endothelial dysfunction,28Savazzi G.M. Cusmano F. Vinci S. et al.Progression of cerebral atrophy in patients on regular hemodialysis treatment: Long-term follow-up with cerebral computed tomography.Nephron. 1995; 69: 29-33Crossref PubMed Scopus (28) Google Scholar cardiovascular events including stroke,29Merkus M.P. Jager K.J. Dekker F.W. et al.Quality of life in patients on chronic dialysis: Self-assessment 3 months after the start of treatment. The Necosad Study Group.Am J Kidney Dis. 1997; 29: 584-592Abstract Full Text PDF PubMed Scopus (299) Google Scholar, 30Neto J.F. Ferraz M.B. Cendoroglo M. et al.Quality of life at the initiation of maintenance dialysis treatment—A comparison between the SF-36 and the KDQ questionnaires.Qual Life Res. 2000; 9: 101-107Crossref PubMed Scopus (55) Google Scholar and carotid atherosclerosis,31Smith C. Silva-Gane M. Chandna S. et al.Choosing not to dialyse: Evaluation of planned non-dialytic management in a cohort of patients with end-stage renal failure.Nephron Clin Pract. 2003; 95: c40-c46Crossref PubMed Scopus (221) Google Scholar all of which contribute to vascular cognitive impairment23Qiu C. De Ronchi D. Fratiglioni L. The epidemiology of the dementias: An update.Curr Opin Psychiatry. 2007; 20: 380-385Crossref PubMed Scopus (342) Google Scholar and neurodegenerative diseases such as Alzheimer's disease.18Posner H.B. Tang M.X. Luchsinger J. et al.The relationship of hypertension in the elderly to AD, vascular dementia, and cognitive function.Neurology. 2002; 58: 1175-1181Crossref PubMed Scopus (271) Google Scholar, 32Casserly I. Topol E. Convergence of atherosclerosis and Alzheimer's disease: Inflammation, cholesterol, and misfolded proteins.Lancet. 2004; 363: 1139-1146Abstract Full Text Full Text PDF PubMed Scopus (452) Google Scholar Ischemic cerebrovascular disease and underlying vascular endothelial pathology, however, appear to play the largest roles in the genesis of cognitive impairment in CKD and hemodialysis patients. Despite remarkably high rates of stroke, surprisingly little has been written about the impact of stroke on the CKD and dialysis populations. The prevalence of stroke in the United States Renal Data System (USRDS) hemodialysis population is 17% and 10% among CKD patients compared with 4% in the general Medicare population.14United States Renal Data System: USRDS 2006 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2006Google Scholar The proportion that experiences a stroke each year is almost as high; the incidence is 15% for hemodialysis patients and 9.5% for CKD patients compared with 2.4% in the non-CKD population. Stroke is also 6 to 9 times more common in hospitalized hemodialysis patients than in nondialysis patients.33Seliger S.L. Gillen D.L. Longstreth Jr., W.T. et al.Elevated risk of stroke among patients with end-stage renal disease.Kidney Int. 2003; 64: 603-609Crossref PubMed Scopus (335) Google Scholar A history of stroke doubles the risk of dementia in both the non-CKD and hemodialysis populations.2Murray A.M. Tupper D.E. Knopman D.S. et al.Cognitive impairment in hemodialysis patients is common.Neurology. 2006; 67: 216-223Crossref PubMed Scopus (493) Google Scholar, 14United States Renal Data System: USRDS 2006 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2006Google Scholar, 34Ivan C.S. Seshadri S. Beiser A. et al.Dementia after stroke: The Framingham Study.Stroke. 2004; 35: 1264-1268Crossref PubMed Scopus (273) Google Scholar In addition to clinically evident acute stroke, hemodialysis patients are at increased risk for subclinical cerebrovascular disease,35Seliger S.L. Sarnak M.J. Subclinical vascular disease of the brain in dialysis patients.Am J Kidney Dis. 2007; 50: 8-10Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar manifested by silent or asymptomatic strokes, and white-matter disease or leukoaraiosis. Silent strokes are diagnosed on brain magnetic resonance imaging as infarcts. White-matter disease is represented by hyperintense signals on T2-weighted images in the subcortical white matter. Both are linked to cognitive and physical function decline in the general population, and both are very common in CKD and dialysis patients.35Seliger S.L. Sarnak M.J. Subclinical vascular disease of the brain in dialysis patients.Am J Kidney Dis. 2007; 50: 8-10Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar Silent strokes occur in up to 33% of the older community population36Bernick C. Kuller L. Dulberg C. et al.Silent MRI infarcts and the risk of future stroke: The cardiovascular health study.Neurology. 2001; 57: 1222-1229Crossref PubMed Scopus (311) Google Scholar or 5 times more common than symptomatic strokes.37Vermeer S.E. Den Heijer T. Koudstaal P.J. et al.Incidence and risk factors of silent brain infarcts in the population-based Rotterdam Scan Study.Stroke. 2003; 34: 392-396Crossref PubMed Scopus (327) Google Scholar Among CKD patients, the prevalence of silent infarcts is inversely related to kidney function as measured by cystatin C in the Cardiovascular Health Study38Seliger S.L. Longstreth Jr., W.T. Katz R. et al.Cystatin C and subclinical brain infarction.J Am Soc Nephrol. 2005; 16: 3721-3727Crossref PubMed Scopus (117) Google Scholar; among hemodialysis patients in another study, the prevalence was 49% or 5 times more common than in control subjects.39Nakatani T. Naganuma T. Uchida J. et al.Silent cerebral infarction in hemodialysis patients.Am J Nephrol. 2003; 23: 86-90Crossref PubMed Scopus (107) Google Scholar Silent strokes are associated with an increased risk of subsequent clinically evident stroke, cognitive and physical decline, and incident dementia36Bernick C. Kuller L. Dulberg C. et al.Silent MRI infarcts and the risk of future stroke: The cardiovascular health study.Neurology. 2001; 57: 1222-1229Crossref PubMed Scopus (311) Google Scholar, 37Vermeer S.E. Den Heijer T. Koudstaal P.J. et al.Incidence and risk factors of silent brain infarcts in the population-based Rotterdam Scan Study.Stroke. 2003; 34: 392-396Crossref PubMed Scopus (327) Google Scholar, 40Schmidt W.P. Roesler A. Kretzschmar K. et al.Functional and cognitive consequences of silent stroke discovered using brain magnetic resonance imaging in an elderly population.J Am Geriatr Soc. 2004; 52: 1045-1050Crossref PubMed Scopus (72) Google Scholar in both the general and CKD/dialysis populations.39Nakatani T. Naganuma T. Uchida J. et al.Silent cerebral infarction in hemodialysis patients.Am J Nephrol. 2003; 23: 86-90Crossref PubMed Scopus (107) Google Scholar, 41Naganuma T. Uchida J. Tsuchida K. et al.Silent cerebral infarction predicts vascular events in hemodialysis patients.Kidney Int. 2005; 67: 2434-2439Crossref PubMed Scopus (67) Google Scholar Although previously the subject of much debate, white-matter disease is now believed to most likely represent microvascular disease because of chronic hypoperfusion. One recent study found strong correlations between ultrastructural hypoxic and ischemic neuropathologic findings in white matter on autopsy and white-matter disease on brain magnetic resonance imaging performed in 465 postmortem subjects.42Fernando M.S. Simpson J.E. Matthews F. et al.White matter lesions in an unselected cohort of the elderly: Molecular pathology suggests origin from chronic hypoperfusion injury.Stroke. 2006; 37: 1391-1398Crossref PubMed Scopus (439) Google Scholar White-matter disease may be of greater clinical significance than cortical infarcts; the amount of white-matter disease correlated more strongly with the severity of cognitive impairment than the size or number of infarcts in 1 recent study of patients with vascular dementia.43Sachdev P.S. Brodaty H. Valenzuela M.J. et al.The neuropsychological profile of vascular cognitive impairment in stroke and TIA patients.Neurology. 2004; 62: 912-919Crossref PubMed Scopus (297) Google Scholar CKD and hemodialysis patients have high rates of white-matter disease,44Martinez-Vea A. Salvado E. Bardaji A. et al.Silent cerebral white matter lesions and their relationship with vascular risk factors in middle-aged predialysis patients with CKD.Am J Kidney Dis. 2006; 47: 241-250Abstract Full Text Full Text PDF PubMed Scopus (58) Google Scholar, 45Fazekas G. Fazekas F. Schmidt R. et al.Brain MRI findings and cognitive impairment in patients undergoing chronic hemodialysis treatment.J Neurol Sci. 1995; 134: 83-88Abstract Full Text PDF PubMed Scopus (145) Google Scholar, 46Savazzi G.M. Cusmano F. Musini S. Cerebral imaging changes in patients with chronic renal failure treated conservatively or in hemodialysis.Nephron. 2001; 89: 31-36Crossref PubMed Scopus (47) Google Scholar, 47Agildere A.M. Kurt A. Yildirim T. et al.MRI of neurologic complications in end-stage renal failure patients on hemodialysis: Pictorial review.Eur Radiol. 2001; 11: 1063-1069Crossref PubMed Scopus (26) Google Scholar and in 1 recent study among peritoneal dialysis patients, 68% had substantial white-matter disease compared with only 17.5% among non-CKD controls.48Kim C.D. Lee H.J. Kim D.J. et al.High prevalence of leukoaraiosis in cerebral magnetic resonance images of patients on peritoneal dialysis.Am J Kidney Dis. 2007; 50: 98-107Abstract Full Text Full Text PDF PubMed Scopus (70) Google Scholar In the Rotterdam49Breteler M.M. van Amerongen N.M. van Swieten J.C. et al.Cognitive correlates of ventricular enlargement and cerebral white matter lesions on magnetic resonance imaging. The Rotterdam Study.Stroke. 1994; 25: 1109-1115Crossref PubMed Scopus (316) Google Scholar and Cardiovascular Health Studies,50Longstreth Jr., W.T. Manolio T.A. Arnold A. et al.Clinical correlates of white matter findings on cranial magnetic resonance imaging of 3301 elderly people. The Cardiovascular Health Study.Stroke. 1996; 27: 1274-1282Crossref PubMed Scopus (1260) Google Scholar white-matter disease was associated with deficits in the cognitive domains of executive function and processing speed more than deficits involving cortical cognitive domains such as memory loss and verbal skills, suggesting a subcortical, vascular pattern of cognitive impairment. Delirium is an acute confusional state affecting global cognition that occurs in up to 30% of hospitalized elderly patients.2Murray A.M. Tupper D.E. Knopman D.S. et al.Cognitive impairment in hemodialysis patients is common.Neurology. 2006; 67: 216-223Crossref PubMed Scopus (493) Google Scholar, 51Inouye S.K. Delirium in older persons.N Engl J Med. 2006; 354: 1157-1165Crossref PubMed Scopus (1467) Google Scholar It is characterized by an acute disturbance of consciousness with a decreased ability to maintain attention; cognitive changes such as memory deficits, disorientation, or language disturbance; reversed sleep-wake cycles; and at times delusions or hallucinations.3American Psychiatric Association: Diagnostic
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