@article {795, title = {Moderate renal impairment and risk of dementia among older adults: the Cardiovascular Health Cognition Study.}, journal = {J Am Soc Nephrol}, volume = {15}, year = {2004}, month = {2004 Jul}, pages = {1904-11}, abstract = {

Renal impairment is associated with an increased risk of carotid atherosclerosis and stroke, determinants of cognitive dysfunction and dementia. The purpose of this study was to determine whether moderate renal impairment is associated with incident dementia among community-dwelling older adults. Participants in the Cardiovascular Health Cognition Study without prevalent dementia (n = 3349) were included in the analysis. Incident dementia was confirmed through neurologic testing. Renal function at baseline was estimated by the inverse of serum creatinine (1/SCr); moderate renal impairment was defined as SCr > or = 1.3 mg/dl for women and > or = 1.5 mg/dl for men. Cox regression models were used to estimate the association of renal impairment with incident dementia. Because SCr is also a function of muscle mass, the authors determined whether the relationship between SCr and dementia was particularly strong among individuals without severe co-morbidity at baseline, as reflected by self-reported general health status. There were 477 incident dementia cases over a median 6 yr follow-up. After adjustment for potential confounders, moderate renal insufficiency was associated with a 37\% increased risk of dementia (95\% CI = 1.06 to 1.78). Similarly, a 0.5-unit decrement in 1/SCr (equivalent to an increase in SCr from 1.0 to 2.0 mg/dl) was associated with a 26\% increased risk (95\% CI = 1.02 to 1.60). These associations were present only among the 84\% of older adults who reported good-excellent health. Among those in good-excellent health, higher SCr was associated with vascular-type dementia but not Alzheimer-type dementia. Moderate renal impairment, reflected by a higher SCr, is associated with an excess risk of incident dementia among individuals in good-excellent health. Strategies to prevent or delay the onset of dementia in patients with moderate renal impairment are needed.

}, keywords = {Aged, Alzheimer Disease, Cardiovascular Diseases, Creatinine, Dementia, Dementia, Vascular, Female, Humans, Kidney, Kidney Diseases, Male, Muscles, Proportional Hazards Models}, issn = {1046-6673}, doi = {10.1097/01.asn.0000131529.60019.fa}, author = {Seliger, Stephen L and Siscovick, David S and Stehman-Breen, Catherine O and Gillen, Daniel L and Fitzpatrick, Annette and Bleyer, Anthony and Kuller, Lew H} } @article {840, title = {Cystatin C and the risk of death and cardiovascular events among elderly persons.}, journal = {N Engl J Med}, volume = {352}, year = {2005}, month = {2005 May 19}, pages = {2049-60}, abstract = {

BACKGROUND: Cystatin C is a serum measure of renal function that appears to be independent of age, sex, and lean muscle mass. We compared creatinine and cystatin C levels as predictors of mortality from cardiovascular causes and from all causes in the Cardiovascular Health Study, a cohort study of elderly persons living in the community.

METHODS: Creatinine and cystatin C were measured in serum samples collected from 4637 participants at the study visit in 1992 or 1993; follow-up continued until June 30, 2001. For each measure, the study population was divided into quintiles, with the fifth quintile subdivided into thirds (designated 5a, 5b, and 5c).

RESULTS: Higher cystatin C levels were directly associated, in a dose-response manner, with a higher risk of death from all causes. As compared with the first quintile, the hazard ratios (and 95 percent confidence intervals) for death were as follows: second quintile, 1.08 (0.86 to 1.35); third quintile, 1.23 (1.00 to 1.53); fourth quintile, 1.34 (1.09 to 1.66); quintile 5a, 1.77 (1.34 to 2.26); 5b, 2.18 (1.72 to 2.78); and 5c, 2.58 (2.03 to 3.27). In contrast, the association of creatinine categories with mortality from all causes appeared to be J-shaped. As compared with the two lowest quintiles combined (cystatin C level, < or =0.99 mg per liter), the highest quintile of cystatin C (> or =1.29 mg per liter) was associated with a significantly elevated risk of death from cardiovascular causes (hazard ratio, 2.27 [1.73 to 2.97]), myocardial infarction (hazard ratio, 1.48 [1.08 to 2.02]), and stroke (hazard ratio, 1.47 [ 1.09 to 1.96]) after multivariate adjustment. The fifth quintile of creatinine, as compared with the first quintile, was not independently associated with any of these three outcomes.

CONCLUSIONS: Cystatin C, a serum measure of renal function, is a stronger predictor of the risk of death and cardiovascular events in elderly persons than is creatinine.

}, keywords = {Aged, Biomarkers, Cardiovascular Diseases, Cerebrospinal Fluid Proteins, Creatinine, Cystatin C, Cystatins, Female, Follow-Up Studies, Glomerular Filtration Rate, Humans, Kidney, Kidney Diseases, Male, Mortality, Multivariate Analysis, Prognosis, Risk}, issn = {1533-4406}, doi = {10.1056/NEJMoa043161}, author = {Shlipak, Michael G and Sarnak, Mark J and Katz, Ronit and Fried, Linda F and Seliger, Stephen L and Newman, Anne B and Siscovick, David S and Stehman-Breen, Catherine} } @article {912, title = {Cystatin C and prognosis for cardiovascular and kidney outcomes in elderly persons without chronic kidney disease.}, journal = {Ann Intern Med}, volume = {145}, year = {2006}, month = {2006 Aug 15}, pages = {237-46}, abstract = {

BACKGROUND: Cystatin C is an alternative measure of kidney function that may have prognostic importance among elderly persons who do not meet standard criteria for chronic kidney disease (estimated glomerular filtration rate [GFR] > or =60 mL/min per 1.73 m2).

OBJECTIVE: To evaluate cystatin C as a prognostic biomarker for death, cardiovascular disease, and incident chronic kidney disease among elderly persons without chronic kidney disease.

DESIGN: Cohort study.

SETTING: The Cardiovascular Health Study, a population-based cohort recruited from 4 communities in the United States.

PARTICIPANTS: 4663 elderly persons.

MEASUREMENTS: Measures of kidney function were creatinine-based estimated GFR by using the Modification of Diet in Renal Disease equation and cystatin C concentration. Outcomes were death, cardiovascular death, noncardiovascular death, heart failure, stroke, myocardial infarction, and incident chronic kidney disease during follow-up (median, 9.3 years).

RESULTS: At baseline, 78\% of participants did not have chronic kidney disease (estimated GFR > or =60 mL/min per 1.73 m2) and mean cystatin C concentration, creatinine concentration, and estimated GFR were 1.0 mg/L, 79.6 micromol/L (0.9 mg/dL), and 83 mL/min per 1.73 m2, respectively. Cystatin C concentrations (per SD, 0.18 mg/L) had strong associations with death (hazard ratio, 1.33 [95\% CI, 1.25 to 1.40]), cardiovascular death (hazard ratio, 1.42 [CI, 1.30 to 1.54]), noncardiovascular death (hazard ratio, 1.26 [CI, 1.17 to 1.36]), incident heart failure (hazard ratio, 1.28 [CI, 1.17 to 1.40]), stroke (hazard ratio, 1.22 [CI, 1.08 to 1.38]), and myocardial infarction (hazard ratio, 1.20 [CI, 1.06 to 1.36]) among these participants. Serum creatinine concentrations had much weaker associations with each outcome and only predicted cardiovascular death. Participants without chronic kidney disease who had elevated cystatin C concentrations (> or =1.0 mg/L) had a 4-fold risk for progressing to chronic kidney disease after 4 years of follow-up compared with those with cystatin C concentrations less than 1.0 mg/L.

LIMITATIONS: Because this study did not directly measure GFR or albuminuria, the extent to which cystatin C may be influenced by nonrenal factors was not determined and participants with albuminuria might have been misclassified as having no kidney disease.

CONCLUSIONS: Among elderly persons without chronic kidney disease, cystatin C is a prognostic biomarker of risk for death, cardiovascular disease, and chronic kidney disease. In this setting, cystatin C seems to identify a "preclinical" state of kidney dysfunction that is not detected with serum creatinine or estimated GFR.

}, keywords = {Aged, Biomarkers, Cardiovascular Diseases, Creatinine, Cystatin C, Cystatins, Glomerular Filtration Rate, Humans, Kidney, Longitudinal Studies, Prognosis, Proportional Hazards Models, Renal Insufficiency, Chronic, Risk Factors}, issn = {1539-3704}, doi = {10.7326/0003-4819-145-4-200608150-00003}, author = {Shlipak, Michael G and Katz, Ronit and Sarnak, Mark J and Fried, Linda F and Newman, Anne B and Stehman-Breen, Catherine and Seliger, Stephen L and Kestenbaum, Brian and Psaty, Bruce and Tracy, Russell P and Siscovick, David S} }