@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 {1285, title = {Mineral metabolism markers and the long-term risk of hip fracture: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {96}, year = {2011}, month = {2011 Jul}, pages = {2186-93}, abstract = {

CONTEXT: Disturbances in mineral metabolism are associated with lower bone mineral density and fracture; however, previous human studies have assessed individual mineral metabolism markers in isolation.

OBJECTIVE: We assessed serum concentrations of 25-hydroxyvitamin D (25-OHD), PTH, and bone-specific alkaline phosphatase (BAP) concentrations individually, and in combination, in association with the long-term risk of hip fracture among a general population of older adults.

DESIGN AND SETTING: We studied 2294 participants from the Cardiovascular Health Study (mean age 74 yr) who were ambulatory and free of hip fracture and known cardiovascular disease at baseline. We used proportional hazards models to evaluate associations of baseline serum 25-OHD, PTH, and BAP concentrations with the time to first hospitalized hip fracture.

RESULTS: During a median of 13 yr of follow-up, 242 participants (10.6\%) developed an incident hip fracture. Serum 25-OHD concentrations less than 15 ng/ml were associated with a 61\% greater adjusted risk of fracture (95\% confidence interval 12-132\% greater). In contrast, neither serum PTH nor BAP concentrations were significantly associated with fracture risk. The association of 25-OHD deficiency with hip fracture was not significantly altered by either PTH or BAP concentrations.

CONCLUSIONS: Serum concentrations of 25-OHD, but not PTH or BAP, are associated with long-term hip fracture risk among ambulatory older adults. These data suggest that 25-OHD is the most relevant mineral metabolism marker of fracture risk among older people.

}, keywords = {Aged, Aged, 80 and over, Alkaline Phosphatase, Biomarkers, Bone Density, Female, Hip Fractures, Humans, Male, Parathyroid Hormone, Risk, Vitamin D}, issn = {1945-7197}, doi = {10.1210/jc.2010-2878}, author = {Robinson-Cohen, Cassianne and Katz, Ronit and Hoofnagle, Andrew N and Cauley, Jane A and Furberg, Curt D and Robbins, John A and Chen, Zhao and Siscovick, David S and de Boer, Ian H and Kestenbaum, Bryan} } @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} } @article {5996, title = {Fibroblast growth factor 23, bone mineral density, and risk of hip fracture among older adults: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {98}, year = {2013}, month = {2013 Aug}, pages = {3323-31}, abstract = {

CONTEXT: Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that also inhibits calcitriol synthesis.

OBJECTIVE: Our objective was to evaluate the relationships of plasma FGF23 concentrations with bone mineral density (BMD) and hip fracture in community-dwelling older adults.

DESIGN AND SETTING: Linear regression and Cox proportional hazard models were used to examine the associations of plasma FGF23 concentrations with BMD and incident hip fracture, respectively. Analyses were also stratified by chronic kidney disease.

PARTICIPANTS: Participants included 2008 women and 1329 men >=65 years from the 1996 to 1997 Cardiovascular Health Study visit.

MAIN OUTCOME MEASURES: Dual x-ray absorptiometry measured total hip (TH) and lumbar spine (LS) BMD in 1291 participants. Hip fracture incidence was assessed prospectively through June 30, 2008 by hospitalization records in all participants.

RESULTS: Women had higher plasma FGF23 concentrations than men (75 [56-107] vs 66 [interquartile range = 52-92] relative units/mL; P < .001). After adjustment, higher FGF23 concentrations were associated with greater total hip and lumbar spine BMD in men only (β per doubling of FGF23 = 0.02, with 95\% confidence interval [CI] = 0.001-0.04 g/cm(2), and 0.03 with 95\% CI = 0.01-0.06 g/cm(2)). During 9.6 {\textpm} 5.1-11.0 years of follow-up, 328 hip fractures occurred. Higher FGF23 concentrations were not associated with hip fracture risk in women or men (adjusted hazard ratio = 0.95, with 95\% CI = 0.78-1.15, and 1.09 with 95\% CI = 0.82-1.46 per doubling of FGF23). Results did not differ by chronic kidney disease status (P > .4 for interactions).

CONCLUSIONS: In this large prospective cohort of community-dwelling older adults, higher FGF23 concentrations were weakly associated with greater lumbar spine and total hip BMD but not with hip fracture risk.

}, keywords = {Aged, Aged, 80 and over, Bone Density, Female, Fibroblast Growth Factors, Hip Fractures, Humans, Longitudinal Studies, Male, Middle Aged, Prospective Studies, Risk, Spinal Fractures}, issn = {1945-7197}, doi = {10.1210/jc.2013-1152}, author = {Jovanovich, Anna and B{\r u}zkov{\'a}, Petra and Chonchol, Michel and Robbins, John and Fink, Howard A and de Boer, Ian H and Kestenbaum, Bryan and Katz, Ronit and Carbone, Laura and Lee, Jennifer and Laughlin, Gail A and Mukamal, Kenneth J and Fried, Linda F and Shlipak, Michael G and Ix, Joachim H} }