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Background: Kidney disease and hypertension commonly coexist, yet the direction of their association is still debated. Objective: To evaluate whether early kidney dysfunction, measured by serum cystatin C levels and urinary albumin excretion, predates hypertension in adults without clinically recognized kidney or cardiovascular disease. Design: Observational cohort study using data from 2000 to 2005. Setting: The MESA (Multi-Ethnic Study of Atherosclerosis), a community-based study of subclinical cardiovascular disease in adults age 45 to 84 years. Participants: 2767 MESA participants without prevalent hypertension, cardiovascular disease, or clinically recognized kidney disease (an estimated glomerular filtration rate Measurements: Cystatin C was measured by using a nephelometer, and urinary albumin and creatinine were measured from a spot morning collection. The primary outcome was incident hypertension, defined as systolic blood pressure of at least 140 mm Hg, diastolic blood pressure of at least 90 mm Hg, or use of an antihypertensive medication. Results: During a median follow-up of 3.1 years, 19.7% of the cohort (545 participants) developed hypertension. After adjustment for established hypertension risk factors, each 15-nmol/L increase in cystatin C was associated with a statistically significant 15% greater incidence of hypertension (P = 0.017). The highest sex-specific quartile of urinary albumin--creatinine ratio was associated with a statistically insignificant 16% greater incidence of hypertension (P = 0.192) compared with the lowest quartile. No statistical evidence suggested a multiplicative interaction. Limitations: Unmeasured characteristics may have confounded observed associations of kidney markers with hypertension. Follow-up was relatively short. Hypertension that may have occurred between study visits or hypertension that was not captured by standard cuff measurements may have been missed. Conclusion: Differences in kidney function, indicated by cystatin C levels, are associated with incident hypertension among individuals without clinical kidney or cardiovascular disease. These population-based findings complement experimental work implicating early kidney damage in the pathogenesis of essential hypertension.

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] [greater than or equal to] 60 mL/min per 1.73 [m.sup.2]). 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 [greater than or equal to] 60 mL/min per 1.73 [m.sup.2]) and mean cystatin C concentration, creatinine concentration, and estimated GFR were 1.0 mg/L, 79.6 [micro]mol/L (0.9 mg/dL), and 83 mL/min per 1.73 [m.sup.2], respectively. Cystatin C concentrations (per SD, 0.18 mg/L) had strong associations with death (hazard ratio, 1.33 [95% Cl, 1.25 to 1.40]), cardiovascular death (hazard ratio, 1.42 [Cl, 1.30 to 1.54]), noncardiovascular death (hazard ratio, 1.26 [Cl, 1.17 to 1.36]), incident heart failure (hazard ratio, 1.28 [Cl, 1.17 to 1.40]), stroke (hazard ratio, 1.22 [Cl, 1.08 to 1.38]), and myocardial infarction (hazard ratio, 1.20 [Cl, 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 ([greater than or equal to] 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.

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 ([+ or -]SD) serum concentrations of cystatin C and creatinine were 82 [+ or -] 25 nmol/L (1.10 [+ or-] 0.33 mg/L) and 89 [+ or -] 34 [micro]mol/L (1.01 [+ or -] 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.

Pregnant women who have blood in their urine have twice the risk of developing preeclampsia as other pregnant women, according to a study of 4,307 women. Preeclampsia is a serious complication of pregnancy.