@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 {827, title = {Cystatin C concentration as a risk factor for heart failure in older adults.}, journal = {Ann Intern Med}, volume = {142}, year = {2005}, month = {2005 Apr 05}, pages = {497-505}, abstract = {

BACKGROUND: Previous studies that evaluated the association of kidney function with incident heart failure may be limited by the insensitivity of serum creatinine concentration for detecting abnormal kidney function.

OBJECTIVE: To compare serum concentrations of cystatin C (a novel marker of kidney function) and creatinine as predictors of incident heart failure.

DESIGN: Observational study based on measurement of serum cystatin C from frozen sera obtained at the 1992-1993 visit of the Cardiovascular Health Study. Follow-up occurred every 6 months.

SETTING: Adults 65 years of age or older from 4 communities in the United States.

PARTICIPANTS: 4384 persons without previous heart failure who had measurements of serum cystatin C and serum creatinine.

MEASUREMENTS: Incident heart failure.

RESULTS: The mean (+/-SD) serum concentrations of cystatin C and creatinine were 82 +/- 25 nmol/L (1.10 +/- 0.33 mg/L) and 89 +/- 34 micromol/L (1.01 +/- 0.39 mg/dL), respectively. During a median follow-up of 8.3 years (maximum, 9.1 years), 763 (17\%) participants developed heart failure. After adjustment for demographic factors, traditional and novel cardiovascular risk factors, cardiovascular disease status, and medication use, sequential quintiles of cystatin C concentration were associated with a stepwise increased risk for heart failure in Cox proportional hazards models (hazard ratios, 1.0 [reference], 1.30 [95\% CI, 0.96 to 1.75], 1.44 [CI, 1.07 to 1.94], 1.58 [CI, 1.18 to 2.12], and 2.16 [CI, 1.61 to 2.91]). In contrast, quintiles of serum creatinine concentration were not associated with risk for heart failure in adjusted analysis (hazard ratios, 1.0 [reference], 0.77 [CI, 0.59 to 1.01], 0.85 [CI, 0.64 to 1.13], 0.97 [CI, 0.72 to 1.29], and 1.14 [CI, 0.87 to 1.49]).

LIMITATIONS: The mechanism by which cystatin C concentration predicts risk for heart failure remains unclear.

CONCLUSIONS: The cystatin C concentration is an independent risk factor for heart failure in older adults and appears to provide a better measure of risk assessment than the serum creatinine concentration. *For a full list of participating Cardiovascular Health Study investigators and institutions, see http://www.chs-nhlbi.org.

}, keywords = {Aged, Biomarkers, Creatinine, Cystatin C, Cystatins, Female, Follow-Up Studies, Glomerular Filtration Rate, Heart Failure, Humans, Incidence, Kidney, Kidney Function Tests, Male, Risk Factors, United States}, issn = {1539-3704}, doi = {10.7326/0003-4819-142-7-200504050-00008}, author = {Sarnak, Mark J and Katz, Ronit and Stehman-Breen, Catherine O and Fried, Linda F and Jenny, Nancy Swords and Psaty, Bruce M and Newman, Anne B and Siscovick, David and Shlipak, Michael G} } @article {876, title = {Cystatin-C and inflammatory markers in the ambulatory elderly.}, journal = {Am J Med}, volume = {118}, year = {2005}, month = {2005 Dec}, pages = {1416}, abstract = {

PURPOSE: Inflammatory factors are elevated in persons with severe renal dysfunction, but their association across all levels of renal function is unclear. We compared cystatin-C, a novel marker of renal function, with creatinine and estimated glomerular filtration rate (eGFR) as predictors of C-reactive protein and fibrinogen levels.

METHODS: This study is a cross-sectional analysis to evaluate cystatin-C, creatinine, and eGFR as predictors of the inflammatory markers C-reactive protein and fibrinogen. Participants included 4637 ambulatory elderly patients from the Cardiovascular Health Study. Multivariate linear regression was used to determine the independent associations of each renal function measurement with the inflammatory marker outcomes.

RESULTS: After adjustment for confounding factors, cystatin-C was correlated with both C-reactive protein (coefficient = 0.13; 95\% confidence interval: 0.10-1.16, P <.0001) and fibrinogen levels (0.15; 0.13-0.18, P <.0001). Associations were larger than those for creatinine and C-reactive protein (0.05; 0.02-0.07, P = .003) or fibrinogen (0.07; 0.04-0.10, P <.0001). Adjusted levels of C-reactive protein increased incrementally across quintiles of cystatin-C, from a median of 2.2 mg/L in quintile 1 to 3.7 mg/L in quintile 5. In contrast, both C-reactive protein and fibrinogen had U-shaped associations with quintiles of creatinine and eGFR, because the inflammatory markers were equivalently elevated in quintiles 1 and 5.

CONCLUSIONS: The finding of a significant linear association of cystatin-C and inflammation markers suggests that even small reductions in renal function may be associated with adverse pathophysiologic consequences.

}, keywords = {Age Factors, Aged, Biomarkers, C-Reactive Protein, Cross-Sectional Studies, Cystatin C, Cystatins, Female, Fibrinogen, Glomerular Filtration Rate, Humans, Kidney Diseases, Male, Predictive Value of Tests, Sensitivity and Specificity}, issn = {1555-7162}, doi = {10.1016/j.amjmed.2005.07.060}, author = {Shlipak, Michael G and Katz, Ronit and Cushman, Mary and Sarnak, Mark J and Stehman-Breen, Catherine and Psaty, Bruce M and Siscovick, David and Tracy, Russell P and Newman, Anne and Fried, Linda} } @article {816, title = {Cystatin-C and mortality in elderly persons with heart failure.}, journal = {J Am Coll Cardiol}, volume = {45}, year = {2005}, month = {2005 Jan 18}, pages = {268-71}, abstract = {

OBJECTIVES: We sought to evaluate cystatin-C, a novel measure of renal function, as a predictor of mortality in elderly persons with heart failure (HF) and to compare it with creatinine.

BACKGROUND: Renal function is an important prognostic factor in patients with HF, but creatinine levels, which partly reflect muscle mass, may be insensitive for detecting renal insufficiency.

METHODS: A total of 279 Cardiovascular Health Study participants with prevalent HF and measures of serum cystatin-C and creatinine were followed for mortality outcomes over a median of 6.5 years.

RESULTS: Median creatinine and cystatin-C levels were 1.05 mg/dl and 1.26 mg/l. Each standard deviation increase in cystatin-C (0.35 mg/l) was associated with a 31\% greater adjusted mortality risk (95\% confidence interval [CI] 20\% to 43\%, p < 0.001), whereas each standard deviation increase in creatinine (0.39 mg/dl) was associated with a 17\% greater adjusted mortality risk (95\% CI 1\% to 36\%, p = 0.04). When both measures were combined in a single adjusted model, cystatin-C remained associated with elevated mortality risk (hazard ratio 1.60, 95\% CI 1.32 to 1.94), whereas creatinine levels appeared associated with lower risk (hazard ratio 0.73, 95\% CI 0.57 to 0.95).

CONCLUSIONS: Cystatin-C is a stronger predictor of mortality than creatinine in elderly persons with HF. If confirmed in future studies, this new marker of renal function could improve risk stratification in patients with HF.

}, keywords = {Age Factors, Aged, Aged, 80 and over, Creatinine, Cystatin C, Cystatins, Female, Follow-Up Studies, Glomerular Filtration Rate, Heart Failure, Humans, Male, Pilot Projects, Predictive Value of Tests, Risk Assessment, Survival Analysis}, issn = {0735-1097}, doi = {10.1016/j.jacc.2004.09.061}, author = {Shlipak, Michael G and Katz, Ronit and Fried, Linda F and Jenny, Nancy Swords and Stehman-Breen, Catherine O and Newman, Anne B and Siscovick, David and Psaty, Bruce M and Sarnak, Mark J} } @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} } @article {1013, title = {Cystatin C and aging success.}, journal = {Arch Intern Med}, volume = {168}, year = {2008}, month = {2008 Jan 28}, pages = {147-53}, abstract = {

BACKGROUND: To our knowledge, the effect of kidney function on successful aging has not been examined.

METHODS: We evaluated the relationship between cystatin C and aging success during a 6-year follow-up in the Cardiovascular Health Study, a community-based cohort of older adults (aged >or= 65 years). Successful aging was defined as remaining free of cardiovascular disease, cancer, and chronic obstructive pulmonary disease and having intact physical and cognitive functioning. In adjusted analysis, an accelerated failure time model was used to evaluate the percentage reduction in successful years by level of cystatin C. A separate Cox proportional hazards model evaluated whether cystatin C was related to incident physical and cognitive disability.

RESULTS: A total of 2140 participants had cystatin C measured and were free of the previously mentioned conditions at baseline. Their mean age was 74 years. The mean cystatin C level, creatinine level, and estimated glomerular filtration rate were 1.06 mg/L, 0.93 mg/dL, and 78 mL/min/1.73 m(2), respectively (to convert cystatin C to nanomoles per liter, multiply by 75; and to convert creatinine to micromoles per liter, multiply by 88.4). A total of 873 participants reached a first event in follow-up, 138 because of cognitive disability, 238 because of physical disability, 34 because of chronic obstructive pulmonary disease, 146 because of cancer, and 317 because of cardiovascular disease. The adjusted percentage reduction in successful life years in the highest vs the lowest quartile of cystatin C was 27\% (95\% confidence interval, 11\%-39\%). The highest vs lowest quartile of cystatin C also was independently associated with incident cognitive or physical disability (hazard ratio, 1.39; 95\% confidence interval, 1.00-1.98).

CONCLUSION: A higher cystatin C level, even within a range of relatively normal kidney function, was associated with unsuccessful aging.

}, keywords = {Aged, Aging, Biomarkers, Creatinine, Cystatin C, Cystatins, Female, Follow-Up Studies, Glomerular Filtration Rate, Humans, Kidney, Male}, issn = {0003-9926}, doi = {10.1001/archinternmed.2007.40}, author = {Sarnak, Mark J and Katz, Ronit and Fried, Linda F and Siscovick, David and Kestenbaum, Brian and Seliger, Stephen and Rifkin, Dena and Tracy, Russell and Newman, Anne B and Shlipak, Michael G} } @article {1012, title = {Cystatin C concentration as a predictor of systolic and diastolic heart failure.}, journal = {J Card Fail}, volume = {14}, year = {2008}, month = {2008 Feb}, pages = {19-26}, abstract = {

BACKGROUND: Risk factors for heart failure (HF) may differ according to ejection fraction (EF). Higher cystatin C, a marker of kidney dysfunction, is associated with incident HF, but previous studies did not determine EF at diagnosis. We hypothesized that kidney dysfunction would predict diastolic HF (DHF) better than systolic HF (SHF) in the Cardiovascular Health Study.

METHODS AND RESULTS: Cystatin C was measured in 4453 participants without HF at baseline. Incident HF was categorized as DHF (EF > or = 50\%) or SHF (EF < 50\%). We compared the association of cystatin C with the risk for DHF and SHF, after adjustment for age, sex, race, medications, and HF risk factors. During 8 years of follow-up, 167 participants developed DHF and 206 participants developed SHF. After adjustment, sequentially higher quartiles of cystatin C were associated with risk for SHF (competing risks hazard ratios 1.0 [reference], 1.99 [95\% confidence interval 1.14-3.48], 2.32 [1.32-4.07], 3.17 [1.82-5.50], P for trend < .001). The risk for DHF was apparent only at the highest cystatin C quartile (hazard ratios 1.0 [reference], 1.09 [0.62-1.89], 1.08 [0.61-1.93], and 1.83 [1.07-3.11]).

CONCLUSIONS: Cystatin C levels are linearly associated with the incidence of systolic HF, whereas only the highest concentrations of cystatin C predict diastolic HF.

}, keywords = {Aged, Aged, 80 and over, Biomarkers, Cohort Studies, Confidence Intervals, Cystatin C, Cystatins, Echocardiography, Female, Heart Failure, Diastolic, Heart Failure, Systolic, Humans, Longitudinal Studies, Male, Predictive Value of Tests, Probability, Proportional Hazards Models, Risk Assessment, Sensitivity and Specificity, Stroke Volume, Survival Analysis}, issn = {1532-8414}, doi = {10.1016/j.cardfail.2007.09.002}, author = {Moran, Andrew and Katz, Ronit and Smith, Nicolas L and Fried, Linda F and Sarnak, Mark J and Seliger, Stephen L and Psaty, Bruce and Siscovick, David S and Gottdiener, John S and Shlipak, Michael G} } @article {1057, title = {Clinical and subclinical cardiovascular disease and kidney function decline in the elderly.}, journal = {Atherosclerosis}, volume = {204}, year = {2009}, month = {2009 May}, pages = {298-303}, abstract = {

OBJECTIVE: Kidney function decline in elderly persons may be the result of microvascular atherosclerosis. As a proxy for the renovascular system, we evaluated the association of clinical and subclinical cardiovascular disease (CVD) with kidney function decline.

METHODS: This study included 4380 subjects from the Cardiovascular Health Study, a longitudinal, community-based cohort of persons aged >or=65 from 4 U.S. communities. Creatinine and cystatin C were measured at baseline, year 3, and year 7; eligible subjects had at least two measures. Creatinine-based estimated glomerular filtration rate (eGFR(creat)) was calculated using the MDRD equation. Rapid kidney function decline was defined as an annual eGFR loss >3 mL/min/1.73 m(2). Predictors of rapid kidney decline included prevalent and subclinical measures of CVD.

RESULTS: Mean decline in eGFR(creat) was 0.4+/-2.6/year; 714 (16\%) had rapid progression. In multivariate models adjusted for demographics, cardiovascular risk factors, and inflammation, prevalent stroke (OR, 95\% CI: 1.55, 1.16-2.08) and heart failure (OR, 95\% CI: 1.80, 1.40-2.31) were independent predictors of rapid kidney decline. Among persons without clinical CV, the subclinical disease measures ankle-arm index <0.9 (OR, 95\% CI: 1.67, 1.25-2.24), common carotid intima-media thickness (>or=1.14 mm) (OR, 95\% CI: 1.52, 1.12-2.06) and internal carotid intima-media thickness (>1.82 mm) (OR, 95\% CI: 1.50, 1.12-2.02) had independent associations with rapid kidney function decline. Results were similar using cystatin C.

CONCLUSION: Clinical atherosclerosis and heart failure and subclinical measures of CVD have independent associations with kidney function decline progression in the elderly, suggesting an underlying role of renal atherosclerosis.

}, keywords = {Age Factors, Aged, Atherosclerosis, Cardiovascular Diseases, Creatinine, Cystatin C, Female, Glomerular Filtration Rate, Heart Failure, Humans, Kidney, Kidney Diseases, Linear Models, Longitudinal Studies, Male, Odds Ratio, Risk Assessment, Risk Factors, Time Factors, United States}, issn = {1879-1484}, doi = {10.1016/j.atherosclerosis.2008.08.016}, author = {Shlipak, Michael G and Katz, Ronit and Kestenbaum, Bryan and Fried, Linda F and Siscovick, David and Sarnak, Mark J} } @article {1110, title = {Cystatin C, albuminuria, and mortality among older adults with diabetes.}, journal = {Diabetes Care}, volume = {32}, year = {2009}, month = {2009 Oct}, pages = {1833-8}, abstract = {

OBJECTIVE: Albuminuria and impaired glomerular filtration rate (GFR) are each associated with poor health outcomes among individuals with diabetes. Joint associations of albuminuria and impaired GFR with mortality have not been comprehensively evaluated in this population.

RESEARCH DESIGN AND METHODS: This is a cohort study among Cardiovascular Health Study participants with diabetes, mean age 78 years. GFR was estimated using serum cystatin C and serum creatinine. Albumin-to-creatinine ratio (ACR) was measured in single-voided urine samples.

RESULTS: Of 691 participants, 378 died over 10 years of follow-up. Cystatin C-estimated GFR <60 ml/min per 1.73 m(2), creatinine-based estimated GFR <60 ml/min per 1.73 m(2), and urine ACR > or =30 mg/g were each associated with increased mortality risk with hazard ratios of 1.73 (95\% CI 1.37-2.18), 1.54 (1.21-1.97), and 1.73 (1.39-2.17), respectively, adjusting for age, sex, race, diabetes duration, hypoglycemic medications, hypertension, BMI, smoking, cholesterol, lipid-lowering medications, prevalent cardiovascular disease (CVD), and prevalent heart failure. Cystatin C-estimated GFR and urine ACR were additive in terms of mortality risk. Cystatin C-estimated GFR predicted mortality more strongly than creatinine-based estimated GFR.

CONCLUSIONS: Albuminuria and impaired GFR were independent, additive risk factors for mortality among older adults with diabetes. These findings support current recommendations to regularly assess both albuminuria and GFR in the clinical care of patients with diabetes; a focus on interventions to prevent or treat CVD in the presence of albuminuria, impaired GFR, or both; and further consideration of cystatin C use in clinical care.

}, keywords = {Aged, Aged, 80 and over, Albuminuria, Creatinine, Cystatin C, Diabetes Mellitus, Female, Glomerular Filtration Rate, Humans, Kidney Function Tests, Male, Risk Factors}, issn = {1935-5548}, doi = {10.2337/dc09-0191}, author = {de Boer, Ian H and Katz, Ronit and Cao, Jie J and Fried, Linda F and Kestenbaum, Bryan and Mukamal, Ken and Rifkin, Dena E and Sarnak, Mark J and Shlipak, Michael G and Siscovick, David S} } @article {1177, title = {Cystatin C and sudden cardiac death risk in the elderly.}, journal = {Circ Cardiovasc Qual Outcomes}, volume = {3}, year = {2010}, month = {2010 Mar}, pages = {159-64}, abstract = {

BACKGROUND: Recent studies have demonstrated an association between moderate kidney dysfunction and sudden cardiac death in people with cardiovascular disease.

METHODS AND RESULTS: The study was a longitudinal analysis among 4465 participants from the Cardiovascular Health Study without prevalent cardiovascular disease at baseline. Cystatin C and creatinine were measured from baseline sera. Sudden cardiac death (SCD) was defined as a sudden pulseless condition from a cardiac origin in a previously stable individual that occurred out of the hospital or in the emergency room. The association between cystatin C tertiles and SCD was determined with multivariate Cox proportional hazards. A similar analysis compared SCD incidence across creatinine-based estimated glomerular filtration rate (eGFR) tertiles. Over a median follow-up of 11.2 years, 91 adjudicated SCD events occurred. The annual incidence of SCD events increased across cystatin C tertiles: 10 events per 10 000 person years in tertile 1, 25 events per 10 000 person years in tertile 2, and 32 events per 10 000 person-years in the highest cystatin C tertile. These associations persisted after multivariate adjustment: hazards ratio=2.72; 95\% confidence interval, 1.44 to 5.16 in tertile 2 and hazards ratio=2.67; 95\% confidence interval, 1.33 to 5.35 in tertile 3. After multivariate adjustment, the rate of SCD also increased in a linear distribution across creatinine-based eGFR tertiles: 15 events per 10 000 person-years in tertile 1, 22 events per 10 000 person-years in tertile 2, and 27 events per 10 000 person-years in tertile 3. No significant associations, however, remained between creatinine-based eGFR and SCD after multivariable adjustment.

CONCLUSIONS: Impaired kidney function, as measured by cystatin C, has an independent association with SCD risk among elderly persons without clinical cardiovascular disease.

}, keywords = {Age Factors, Aged, Biomarkers, Chi-Square Distribution, Creatinine, Cystatin C, Death, Sudden, Cardiac, Female, Glomerular Filtration Rate, Humans, Incidence, Kidney Diseases, Longitudinal Studies, Male, Proportional Hazards Models, Risk Assessment, Risk Factors, Time Factors, United States, Up-Regulation}, issn = {1941-7705}, doi = {10.1161/CIRCOUTCOMES.109.875369}, author = {Deo, Rajat and Sotoodehnia, Nona and Katz, Ronit and Sarnak, Mark J and Fried, Linda F and Chonchol, Michel and Kestenbaum, Bryan and Psaty, Bruce M and Siscovick, David S and Shlipak, Michael G} } @article {1230, title = {Chronic kidney disease and the risk of end-stage renal disease versus death.}, journal = {J Gen Intern Med}, volume = {26}, year = {2011}, month = {2011 Apr}, pages = {379-85}, abstract = {

BACKGROUND: Among older adults with chronic kidney disease (CKD), the comparative event rates of end-stage renal disease (ESRD) and cause-specific death are unknown.

OBJECTIVE: To compare the rates of ESRD, cardiovascular and non-cardiovascular death and examine risk factors for ESRD and all-cause mortality in Cardiovascular Health Study (CHS) participants.

DESIGN: The CHS is a longitudinal cohort study of community-dwelling adults aged 65 years and older.

PARTICIPANTS: 1,268 participants with an estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73 m(2) were followed until the time of first event (ESRD, cardiovascular or non-cardiovascular death) or until March 31, 2003.

MAIN MEASURES: The outcomes were ESRD, cardiovascular- and non-cardiovascular death. Rates of each event were calculated, and a Cox Proportional Hazards Model with a competing risk framework was used to examine risk factors for ESRD as compared with death. Predictors included age, gender, race, BMI, hypertension, diabetes, cardiovascular disease, heart failure, tobacco use, eGFR, and total cholesterol.

KEY RESULTS: During 9.7 years of follow-up, 5\% of the cohort progressed to ESRD, and 61\% of the cohort died. The rate (per 100 person-years) was 0.5 for ESRD and 6.8 for all-cause mortality (3.0 for cardiovascular and 3.8 for non-cardiovascular mortality). In the competing risk framework, lower eGFR, male gender, African-American race, and higher BMI were associated with an increased risk of ESRD.

CONCLUSIONS: Older adults with CKD are 13-fold more likely to die from any cause than progress to ESRD and are 6-fold more likely to die from cardiovascular causes than develop ESRD.

}, keywords = {Aged, Aged, 80 and over, Cause of Death, Cohort Studies, Female, Follow-Up Studies, Humans, Kidney Failure, Chronic, Longitudinal Studies, Male, Prospective Studies, Renal Insufficiency, Chronic, Risk Factors, Treatment Outcome}, issn = {1525-1497}, doi = {10.1007/s11606-010-1511-x}, author = {Dalrymple, Lorien S and Katz, Ronit and Kestenbaum, Bryan and Shlipak, Michael G and Sarnak, Mark J and Stehman-Breen, Catherine and Seliger, Stephen and Siscovick, David and Newman, Anne B and Fried, Linda} } @article {1286, title = {Chronic kidney disease in octogenarians.}, journal = {Clin J Am Soc Nephrol}, volume = {6}, year = {2011}, month = {2011 Jun}, pages = {1410-7}, abstract = {

BACKGROUND AND OBJECTIVES: There are limited data on the prevalence of chronic kidney disease (CKD) and its clinical importance in the very old. We examined the prevalence of CKD in octogenarians and its association with cardiovascular disease (CVD).

DESIGN, SETTING, PARTICIPANTS, \& MEASUREMENTS: In a cross-sectional analysis of 1028 participants from the Cardiovascular Health Study All Stars, we evaluated association of prevalent CKD with CVD using multivariable logistic regression. CKD was defined as eGFR of <60 ml/min per 1.73 m(2). GFR was estimated using CKD-Epi creatinine and cystatin C equations that incorporate coefficients for age, gender, and race (eGFR(EPI), eGFR(CYS3var)) and the one-variable cystatin C equation (eGFR(CYS1var)). Prevalent CVD was defined as a composite of coronary heart disease, heart failure, and stroke.

RESULTS: Mean age was 86 years, 64\% were women, 86\% were Caucasians, 14\% had diabetes, and 39\% had prevalent CVD. Mean eGFR(EPI), eGFR(CYS3var), and eGFR(CYS1var) were 59, 62, and 70 ml/min per 1.73 m(2), and 51\%, 46\%, and 33\% had CKD, respectively. Associations of CKD with CVD varied by equation in adjusted analyses: CKD(EPI) (OR, 1.53; 95\% CI, 1.15 to 2.03), CKD(CYS3var) (OR, 1.67; 95\% CI, 1.25, 2.23), and CKD(CYS1var) (OR, 2.09; 95\% CI, 1.55, 2.83).

CONCLUSIONS: Reduced eGFR is highly prevalent in octogenarians, and the eGFR(CYS1var) equation yielded the lowest prevalence of CKD but the strongest association with prevalent CVD. Because there are no validated estimating equations in the elderly, estimation of kidney function on the basis of on any one equation should be interpreted with caution.

}, keywords = {Age Factors, Aged, 80 and over, Analysis of Variance, Biomarkers, Cardiovascular Diseases, Chi-Square Distribution, Chronic Disease, Creatinine, Cross-Sectional Studies, Cystatin C, Diabetes Mellitus, Female, Glomerular Filtration Rate, Humans, Kidney, Kidney Diseases, Logistic Models, Male, Models, Biological, Prevalence, Risk Assessment, Risk Factors, United States}, issn = {1555-905X}, doi = {10.2215/CJN.08801010}, author = {Shastri, Shani and Tighiouart, Hocine and Katz, Ronit and Rifkin, Dena E and Fried, Linda F and Shlipak, Michael G and Newman, Anne B and Sarnak, Mark J} } @article {1256, title = {Cystatin C identifies chronic kidney disease patients at higher risk for complications.}, journal = {J Am Soc Nephrol}, volume = {22}, year = {2011}, month = {2011 Jan}, pages = {147-55}, abstract = {

Although cystatin C is a stronger predictor of clinical outcomes associated with CKD than creatinine, the clinical role for cystatin C is unclear. We included 11,909 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS) and assessed risks for death, cardiovascular events, heart failure, and ESRD among persons categorized into mutually exclusive groups on the basis of the biomarkers that supported a diagnosis of CKD (eGFR <60 ml/min per 1.73 m(2)): creatinine only, cystatin C only, both, or neither. We used CKD-EPI equations to estimate GFR from these biomarkers. In MESA, 9\% had CKD by the creatinine-based equation only, 2\% had CKD by the cystatin C-based equation only, and 4\% had CKD by both equations; in CHS, these percentages were 12, 4, and 13\%, respectively. Compared with those without CKD, the adjusted hazard ratios (HR) for mortality in MESA were: 0.80 (95\% CI 0.50 to 1.26) for CKD by creatinine only; 3.23 (95\% CI 1.84 to 5.67) for CKD by cystatin C only; and 1.93 (95\% CI 1.27 to 2.92) for CKD by both; in CHS, the adjusted HR were 1.09 (95\% CI 0.98 to 1.21), 1.78 (95\% CI 1.53 to 2.08), and 1.74 (95\% CI 1.58 to 1.93), respectively. The pattern was similar for cardiovascular disease (CVD), heart failure, and kidney failure outcomes. In conclusion, among adults diagnosed with CKD using the creatinine-based CKD-EPI equation, the adverse prognosis is limited to the subset who also have CKD according to the cystatin C-based equation. Cystatin C may have a role in identifying persons with CKD who have the highest risk for complications.

}, keywords = {Aged, Aged, 80 and over, Biomarkers, Cardiovascular Diseases, Chronic Disease, Creatinine, Cystatin C, Disease Progression, Female, Glomerular Filtration Rate, Heart Failure, Humans, Kidney Diseases, Kidney Failure, Chronic, Male, Middle Aged, Predictive Value of Tests, Retrospective Studies, Risk Factors}, issn = {1533-3450}, doi = {10.1681/ASN.2010050483}, author = {Peralta, Carmen A and Katz, Ronit and Sarnak, Mark J and Ix, Joachim and Fried, Linda F and de Boer, Ian and Palmas, Walter and Siscovick, David and Levey, Andrew S and Shlipak, Michael G} } @article {7377, title = {Cystatin C versus creatinine in determining risk based on kidney function.}, journal = {N Engl J Med}, volume = {369}, year = {2013}, month = {2013 Sep 05}, pages = {932-43}, abstract = {

BACKGROUND: Adding the measurement of cystatin C to that of serum creatinine to determine the estimated glomerular filtration rate (eGFR) improves accuracy, but the effect on detection, staging, and risk classification of chronic kidney disease across diverse populations has not been determined.

METHODS: We performed a meta-analysis of 11 general-population studies (with 90,750 participants) and 5 studies of cohorts with chronic kidney disease (2960 participants) for whom standardized measurements of serum creatinine and cystatin C were available. We compared the association of the eGFR, as calculated by the measurement of creatinine or cystatin C alone or in combination with creatinine, with the rates of death (13,202 deaths in 15 cohorts), death from cardiovascular causes (3471 in 12 cohorts), and end-stage renal disease (1654 cases in 7 cohorts) and assessed improvement in reclassification with the use of cystatin C.

RESULTS: In the general-population cohorts, the prevalence of an eGFR of less than 60 ml per minute per 1.73 m(2) of body-surface area was higher with the cystatin C-based eGFR than with the creatinine-based eGFR (13.7\% vs. 9.7\%). Across all eGFR categories, the reclassification of the eGFR to a higher value with the measurement of cystatin C, as compared with creatinine, was associated with a reduced risk of all three study outcomes, and reclassification to a lower eGFR was associated with an increased risk. The net reclassification improvement with the measurement of cystatin C, as compared with creatinine, was 0.23 (95\% confidence interval [CI], 0.18 to 0.28) for death and 0.10 (95\% CI, 0.00 to 0.21) for end-stage renal disease. Results were generally similar for the five cohorts with chronic kidney disease and when both creatinine and cystatin C were used to calculate the eGFR.

CONCLUSIONS: The use of cystatin C alone or in combination with creatinine strengthens the association between the eGFR and the risks of death and end-stage renal disease across diverse populations. (Funded by the National Kidney Foundation and others.).

}, keywords = {Creatinine, Cystatin C, Glomerular Filtration Rate, Humans, Kidney Failure, Chronic, Kidney Function Tests, Reference Standards, Renal Insufficiency, Chronic, Risk, Risk Assessment}, issn = {1533-4406}, doi = {10.1056/NEJMoa1214234}, author = {Shlipak, Michael G and Matsushita, Kunihiro and Arnl{\"o}v, Johan and Inker, Lesley A and Katz, Ronit and Polkinghorne, Kevan R and Rothenbacher, Dietrich and Sarnak, Mark J and Astor, Brad C and Coresh, Josef and Levey, Andrew S and Gansevoort, Ron T} }