Carotid intima-media thickness and atherosclerotic plaques are associated with renal function decline: a 14-year longitudinal population-based study

BACKGROUND

Chronic kidney disease (CKD) leads to increased morbidity and mortality. The underlying causes of CKD are often similar to those of atherosclerosis. We investigated whether carotid atherosclerotic parameters are associated with renal function decline.

METHODS

Within the population-based Study of Health in Pomerania (SHIP), Germany, 2904 subjects were observed over 14 years. The carotid intima-media thickness (cIMT) as well as carotid plaques were measured by standardized B-mode ultrasound protocol. CKD is defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and albuminuria as urinary albumin-creatinine ratio (ACR) ≥30 mg/g. eGFR was calculated by the full age spectrum (FAS) equation and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Mixed models were applied to associate carotid parameters with change in renal function longitudinally and adjusted for confounding.

RESULTS

The age range of the study sample was 25-86 years with a median of 54 years at baseline. In longitudinal analyses, subjects with high cIMT and the presence of plaques at baseline showed a greater decrease in eGFR (cIMT: FAS-eGFR: P < .001, CKD-EPI-eGFR: P < .001; plaques: FAS-eGFR: P < .001, CKD-EPI-eGFR: n.s.) as well as an increased risk of developing CKD during the follow-up (cIMT: FAS-eGFR: P = .001, CKD-EPI-eGFR: P = .04; plaques: FAS-eGFR: P = .008, CKD-EPI-eGFR: P = .001). There was no association between atherosclerotic parameters and the risk of developing albuminuria.

CONCLUSIONS

cIMT and carotid plaques are associated with renal function decline as well as CKD in a population-based sample. Furthermore, the FAS equation adapts best to this study population.

Blood pressure and vascular determinants of glomerular filtration rate decline in diabetic kidney disease

Objective

In patients with type 2 diabetes and diabetic kidney disease (DKD), explore the relationship between estimated glomerular filtration rate decline (eGFR-d) and simultaneously assessed vascular risk markers including office, ambulatory or central blood pressure, pulse pressure, carotid-femoral pulse wave velocity (PWV), carotid intima-media thickness (IMT) and renal resistive indexes (RRI).

Research design and methods

At baseline, vascular risk markers were measured in addition to the routine clinical workup. The eGFR-d was based on 2000-2019 creatinine values. Parameters were compared by eGFR-d quartiles. Regression models of eGFR-d and vascular markers were assessed.

Results

In total, 135 patients were included. Mean age was 63.8 ± 10.8y, baseline eGFR 60.2 ± 26.4 ml/min/1.73 m2 and urine albumin-creatinine ratio (ACR) 49 ± 108 mg/mmol. Mean eGFR-d was based on 43 ± 39 creatinine values within a time span of 7.0 ± 1.9y. The average yearly eGFR decline was -1.8 ± 3.0 ml/min/1.73 m2 ranging from -5.8 ± 2.3 in the first quartile to +1.4 ± 1.7 in the fourth quartile. Mean 24 h systolic (SBP) and diastolic (DBP) blood pressure were 126 ± 17 and 74 ± 9 mmHg. Mean PWV was 11.8 ± 2.8 m/s, RRI 0.76 ± 0.07 and IMT 0.77 ± 0.21 mm. SBP and pulse pressure correlated with eGFR-d but not DBP. 24 h SBP stood out as a stronger predictor of eGFR-d than office or central SBP. PWV and RRI correlated with eGFR decline in univariate, but not multivariate regression models including 24 SBP and ACR.

Conclusions

In this study, eGFR decline was highly variable in patients with type 2 diabetes and DKD. Twenty-four hour SBP provided an added value to the routine measurement of ACR in predicting eGFR decline, whereas PWV and RRI did not.

Narrative Review of Carotid disease and the kidney

Patients with chronic kidney disease (CKD) have an increased cardiovascular (CV) risk that is only in part explained by established risk factors. Carotid arteriosclerosis and atherosclerosis are increased in CKD, play a role in the causation of CV disease in these patients and can affect the progression of renal disease. The arterial stiffening process is evident even in CKD patients with a very mild reduction of glomerular filtration rate (GFR) whereas arterial thickening is evident in more advanced stages. Possible mechanisms include functional and structural alterations of the arterial wall. Arterial stiffness can mediate the effect of CKD on target organs (i.e., brain, kidney and heart). In this review we discuss the arterial phenotype of patients with CKD. This is characterized by increased common carotid artery stiffness and outward remodeling (enlargement and thickening of the arterial wall) and a normal/reduced stiffness paired with an inward remodeling (narrowing of the arterial wall) of muscular arteries. We also discuss the consequences of carotid dysfunction, including the involvement of large elastic arteries stiffness on ventricular-vascular coupling, the mechanisms linking carotid stiffening and increased cardio- and cerebrovascular risk in CKD patients, and the therapeutic options to improve carotid function.

The change in kidney function was associated with carotid artery plaque in a community-based population: A cohort study

BACKGROUND AND AIMS

We performed the current study to evaluate the association between dynamic change in estimated glomerular filtration rate (eGFR) and the risk of carotid artery plaque (CAP) in a community-based population.

METHODS AND RESULTS

A total number of 37,093 Chinese adults (21,790 men and 15,303 women, aged 42.6 ± 11.6 years) free of chronic kidney diseases were enrolled. The change in eGFR was calculated based on two measurements in 2013 and 2014 (mean interval: 1.2 y). Participants were further classified into three groups based on the change in eGFR: fast-decrease (<-3.3%), stable (from -3.3% to 3.3%), and fast-increase (≥3.3%). CAP was annually assessed by ultrasound B model throughout the study (2013-2018). We have identified 1,624 new cases of CAP (16.0 per 1000 person-year) during follow up. Compared to participants with stable eGFR, participants in both fast-decrease and fast-increase groups were associated with 1.99 folds (HR = 1.99, 95% CI: 1.54, 2.57) and 3.15 folds (HR = 3.15, 95% CI: 2.38, 4.16) higher likelihood of developing CAP. The association between continuous change in eGFR and the risk of CAP demonstrate a "U" shape. Sensitivity analysis generated similar results with main analysis.

CONCLUSIONS

Both fast decrease and increase in eGFR were associated with the risk of developing CAP in Chinese adults.

Independent associations of urinary albumin-to-creatinine ratio and serum cystatin C with carotid intima-media thickness in community-living Taiwanese adults

Background

Renal function is a key factor of cardiovascular disease. Carotid intima-media thickness (IMT) has been widely used as a marker of early subclinical atherosclerosis. The determinants of cystatin C, a novel marker of renal function, have not been extensively studied in the Asian population. This study aimed to assess the determinants of cystatin C and explore whether carotid thickening was associated with urinary albumin-creatinine ratio and cystatin C in community-living Taiwanese adults.

Methods

A cross-sectional study was conducted on participants from Taichung City, Taiwan. All the participants underwent carotid ultrasonography. Carotid IMT-mean and IMT-maximum were derived. Kidney biomarkers were measured on the basis of urinary albumin-to-creatinine ratio (ACR) and cystatin C. Multiple linear regression analysis was used.

Results

A total of 1032 individuals were recruited, and 469 (45.44%) of them were men. An increased cystatin C level was significantly associated with older age, male gender, lack of physical activity, low HDL cholesterol, abdominal obesity, high hs-CRP, and high ACR. The multivariate-adjusted mean carotid IMT-mean and IMT-maximum values significantly increased by 80.49 and 195.23 μm for every one unit of increase in cystatin C level and by 0.07 and 0.14 μm for every one unit of increase in ACR, respectively (all p < 0.001 except ACR on IMT-maximum with p < 0.01). Lack of physical activity, low HDL, abdominal obesity, high hs-CRP, and high ACR were the determinants of cystatin C.

Conclusion

Cystatin C and ACR were strongly and linearly associated with carotid thickening, a marker of subclinical atherosclerosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02123-x.

Serum Cystatin C and Arterial Stiffness in Middle-Aged and Elderly Adults without Chronic Kidney Disease: A Population-Based Study

BACKGROUND Cystatin C is a protease inhibitor that is increased in the serum of patients with chronic kidney disease (CKD) and is associated with an increased risk of developing cardiovascular disease (CVD). This study aimed to evaluate the association between serum levels of cystatin C and arterial stiffness, associated with dyslipidemia, obesity, and increased pulse pressure, in middle-aged and elderly individuals without CKD in a population in China. MATERIAL AND METHODS A cross-sectional population-based study included 1,138 patients aged ≥40 years without CKD, defined as an estimated glomerular filtration rate measured by serum creatinine (eGFRSCr) ≥60 ml/min/1.73 m². Study participants provided clinical details, including height and weight, and blood samples for serum measurements of cystatin C and lipid profiles and completed a clinical questionnaire. Pulse pressure was calculated as the mean systolic pressure (SBP) minus the diastolic pressure (DBP). Data underwent multivariate logistic regression analysis. RESULTS An increase in serum levels of cystatin C was associated with an increased risk of arterial stiffness. Each standard deviation in the increase of cystatin C resulted in a 22% increased risk of dyslipidemia, a 27% increased risk of obesity, and a 24% increased risk of increased pulse pressure, after adjusting for confounders. These associations were further confirmed in a sensitivity analysis by excluding participants with hypertension, diabetes, and patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). CONCLUSIONS In middle-aged and elderly individuals without CKD, arterial stiffness determined by obesity, dyslipidemia and increased pulse pressure, was significantly associated with increased serum levels of cystatin C.

Presence of Carotid Plaque Is Associated with Rapid Renal Function Decline in Patients with Type 2 Diabetes Mellitus and Normal Renal Function

BACKGROUND

Recent evidences indicate that early rapid renal function decline is closely associated with the development and progression of diabetic kidney disease. We have investigated the association between carotid atherosclerosis and rapid renal function decline in patients with type 2 diabetes mellitus and preserved renal function.

METHODS

In a prospective, multicenter cohort, a total of 967 patients with type 2 diabetes mellitus and preserved renal function were followed for 6 years with serial estimated glomerular filtration rate (eGFR) measurements. Common carotid intima-media thickness (CIMT) and presence of carotid plaque were assessed at baseline. Rapid renal function decline was defined as an eGFR decline >3.3% per year.

RESULTS

Over a median follow-up of 6 years, 158 participants (16.3%) developed rapid renal function decline. While there was no difference in CIMT, the presence of carotid plaque in rapid decliners was significantly higher than in non-decliners (23.2% vs. 12.2%, P<0.001). In multivariable logistic regression analysis, presence of carotid plaque was an independent predictor of rapid renal function decline (odds ratio, 2.33; 95% confidence interval, 1.48 to 3.68; P<0.0001) after adjustment for established risk factors. The model including the carotid plaque had better performance for discrimination of rapid renal function decline than the model without carotid plaque (area under the receiver operating characteristic curve 0.772 vs. 0.744, P=0.016).

CONCLUSION

Close monitoring of renal function and early intensive management may be beneficial in patients with type 2 diabetes mellitus and carotid plaques.

Renal size and cardiovascular risk in prepubertal children

Renal size is an important parameter for the evaluation and diagnosis of kidney disease and has been associated with several cardiovascular risk factors in patients with kidney failure. These results are however discordant and studies in healthy children are lacking. We aimed to study the association between renal size (length and volume) and cardiovascular risk parameters in healthy children. Clinical, analytical and ultrasound parameters [renal length, renal volume, perirenal fat and carotid intima-media thickness (cIMT)] were determined in 515 healthy prepubertal children (176 lean, 208 overweight and 131 obese). Renal length and volume associated significantly and positively with several anthropometric and cardiovascular risk parameters including cIMT and systolic blood pressure (SBP) (all p < 0.001). Renal length and volume associated with cIMT and SBP in all study subgroups, but these associations were predominant in obese children, in whom these associations were independent after adjusting for age, gender and BSA (all p < 0.05). In multivariate analyses in the study subjects as a whole, renal length was an independent predictor of cIMT (β = 0.310, p < 0.0001) and SBP (β = 0.116, p = 0.03). Renal size associates with cIMT and SBP, independent of other well-established cardiovascular risk factors, and may represent helpful parameters for the early assessment of cardiovascular risk in children.

Association between renal damage markers and carotid atherosclerosis in Afro-descendants with hypertension belonging to a minority ethnic group from Brazil

Ethnicity appears to play an important role in the prevalence and severity of hypertension, renal disease, and atherosclerosis. A cross-sectional study was conducted, including 206 Afro-descendants with hypertension, living in the remaining quilombo communities. These subjects underwent a carotid intima-media thickness (CIMT) assessment. The presence of renal injury was assessed by: (1) The glomerular filtration rate (GFR) estimated by the formula CKD-EPI using creatinine and cystatin C and (2) Albuminuria (ACR ≥30 mg/g). The Poisson distribution model was set with robust variance to identify factors associated with carotid atherosclerosis. The statistical analysis was performed using the Stata 12.0 software, adopting a significance level of 5%. Most subjects were women (61.65%); the average age was 61.32 (±12.44) years. Subjects (12.62%) were identified with GFR <60 mL/min/1.73 m2 and 22.8% with albuminuria. Patients (59.22%) presented with a high CIMT. In the adjusted regression model, age ≥60 years (PR: 1.232 [CI 95%:1.091-1.390], p value = .001), ACR ≥30 mg/g (PR: 1.176 [CI 95%: 1.007-1.373], p = .040), and GFR/CKD-EPI using cystatin C (PR: 1.250 [CI 95%: 1.004-1.557], p = .045) were independently associated with carotid atherosclerosis. The occurrence of atherosclerotic lesions was high in the studied group. Age, albuminuria, and GFR (estimated by the formula CKD-EPI using cystatin C) influenced the prevalence of carotid atherosclerosis.

Renal function and carotid atherosclerosis in adults with no known kidney disease

BACKGROUND AND AIMS

A high prevalence of atherosclerotic lesions characterizes patients with chronic kidney disease, though there is little data on the relationship between kidney function and atherosclerotic changes in the healthy population or in people with no known renal impairment. The aim of our study was to analyze, in a comprehensive general population with no known kidney disease, the relationship between renal function and subclinical carotid atherosclerotic damage.

METHODS AND RESULTS

A general real-life population of 611 participants (233 males and 378 females; age ≥18 years) with no known kidney failure was selected for the study. The glomerular filtration rate (GFR) was estimated according to the CKD-EPI equation. Carotid intima-media thickness (c-IMT) and plaques were assessed by duplex Doppler ultrasonography of the carotid vessels. The main laboratory and metabolic parameters were evaluated in all participants. When we divided the overall study population into tertiles according to GFR values (I tertile <85; II tertile: 85-99; III tertile >99 ml/min/1.73 m²), the c-IMT mean values and the prevalence of carotid plaques decreased with the increasing tertile of GFR. On univariate analysis, c-IMT was significantly correlated with eGFR (r = -0.33; p < 0.001), serum creatinine (r = 0.17; p < 0.001), and other variables such as age, systolic blood pressure, waist circumference, fasting or random glycemia, and glycated hemoglobin (HbA₁c). On multiple regression analysis, serum creatinine was associated with c-IMT (β = 0.069; p = 0.017), independent of other covariates.

CONCLUSION

Our study seems to suggest the importance of early identification of people with near normal or mildly decreased renal function due to its association with carotid atherosclerosis.

[Chronic kidney failure and carotid atherosclerosis in diabetic patient]

INTRODUCTION

Chronic kidney failure is an independent risk factor of cardiovascular disease. Its association with carotid atherosclerosis remains controversial. The purpose of our study was to assess the factors associated with carotid atherosclerosis specially the components of chronic kidney disease.

METHODS

In a cross-sectional study, we enrolled type 1 or type 2 diabetic patients from the endocrinology an diabetology department of the military hospital of Rabat assigned in two groups according to the presence or absence of carotid atherosclerosis. Kidney function was assessed based on albuminuria and the estimated glomerular filtration rate calculated using the "modification of diet in renal disease" equation. A multiple logistic regression analysis was performed to identify independent factors associated with carotid atherosclerosis.

RESULTS

One hundred and six diabetic patients were enrolled including 96 type 2 diabetic patients. Age (P<0.001), diabetes duration (P=0.04), hypertension (P=0.002), peripheral arterial disease (P<0.001) and chronic kidney failure (P=0.001) were significantly associated with carotid atherosclerosis. After adjusting for age, hypertension, diabetes duration and peripheral arterial disease, chronic kidney failure was an independent factor associated with carotid atherosclerosis (OR: 5.46; 95%IC: 1.29-23.01; P=0.021).

CONCLUSION

Our data suggest that chronic kidney failure is associated with carotid atherosclerosis in diabetic patients independently of the common cardiovascular risk factors.

Variations in glomerular filtration rate are associated with subclinical atherosclerosis in healthy postmenopausal women

OBJECTIVE

This study aims to evaluate the potential effects of renal function variations on vascular structure before the development of hypertension.

METHODS

This pilot study included 141 postmenopausal women without evidence of renal dysfunction or hypertension. Markers of renal function and levels of glomerular filtration rate (GFR)--using standard calculations (GFR based on levels of creatinine [GFR(epi)]) and newer creatinine and/or cystatin calculations (GFR based on levels of creatinine and cystatin [GFR(cr cystatin)] and GFR based on levels of cystatin [GFR(cystatin)])--were associated with hemodynamic parameters and markers of vascular structure (intima-media thickness [IMT] and presence of atheromatous plaques in carotid and femoral arteries).

RESULTS

Levels of GFR(epi), GFR(cr cystatin), and GFR(cystatin) exhibited a significant negative correlation with femoral artery IMT, whereas levels of GFR(epi) correlated significantly with mean carotid bulb (CB) IMT. Multivariate analysis showed that CB-IMT was predicted by GFR(epi) levels and age (β-coefficient = -0.212, P = 0.020), whereas femoral artery IMT was predicted by GFR(epi) levels (β-coefficient = -0.293, P = 0.001). GFR(epi) levels lower than the 25th percentile were associated with higher CB-IMT (P = 0.009), femoral artery IMT (P = 0.001), and combined IMT (P = 0.035) compared with higher GFR(epi) levels. Moreover, GFR(epi) levels greater than the 25th percentile were associated with lower odds for the presence of atherosclerotic plaques at the CB and carotid arteries combined (CB: odds ratio, 0.146; P = 0.006; combined: odds ratio, 0.249; P = 0.043) compared with lower GFR(epi) levels.

CONCLUSIONS

A mild decrease in renal function within normal limits of GFR is independently associated with the presence of subclinical atherosclerosis in a sample of apparently healthy young postmenopausal women. Assessment of GFR using creatinine (vs cystatin C) levels is a more sensitive marker of its association with IMT and atherosclerotic plaques in this postmenopausal population.

Correlation between Carotid Intima-Media Thickness and Early-Stage Chronic Kidney Disease: Results from Asymptomatic Polyvascular Abnormalities in Community Study

OBJECTIVE

Chronic kidney disease (CKD) might be a potential independent risk factor for increased carotid intima-media thickness (IMT). Our aim is to determine whether mild to moderate kidney dysfunction is associated with increased carotid IMT.

METHODS

We employed 3629 subjects free from clinical cardiovascular diseases at the baseline visit of the Asymptomatic Polyvascular Abnormalities in Community Study. Kidney function was evaluated in terms of estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration China equation. The mean of the maximal internal and common carotid IMT was measured by means of high-resolution B-mode ultrasound. Univariable linear regressions and multivariate logistic regressions were used to evaluate the independent association between kidney function and carotid IMT.

RESULTS

In the unadjusted linear analysis, carotid IMT showed a significant negative correlation with eGFR in both male (r = -.346, P < .001) and female (r = -.253, P < .001) subjects. After adjustment for age, traditional vascular risk factors (smoking, diabetes, systolic blood pressure, diastolic blood pressure, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, and antihypertensive drug use), and nontraditional risk factors (C-reactive protein and homocysteine), the association remained significant. The odds ratio for increased IMT was 1.299 (95% confidence interval [CI], 1.062-1.588) in the group with an eGFR of 60-89 mL/minute/1.73 m(2) and 1.789 (95% CI, 1.203-2.660) in the group with an eGFR of 30-59 mL/minute/1.73 m(2).

CONCLUSIONS

Increased IMT is associated with early-stage CKD. This association is independent of traditional and nontraditional cardiovascular risk factors. Early detection of kidney dysfunction is important to improve risk stratification of atherosclerotic disease.

Association Between Kidney Dysfunction and Carotid Atherosclerosis in Community-Based Older Adults in China

We investigated the association between kidney dysfunction and carotid atherosclerosis in community-based older adults. This study consisted of 1257 participants, aged 55 years and older and free of cardiovascular disease. Kidney dysfunction was classified as mild, moderate, and severe (estimated glomerular filtration rate, 45-59, 30-44, and <30 mL/min/1.73 m2, respectively). We found that the mean common carotid artery intima–media thickness (CCA-IMT) progressively increased with decrement in kidney function ( P < .001). Even mild kidney dysfunction was significantly associated with CCA-IMT thickening (CCA-IMT ≥1.0 mm; odds ratio [OR] 1.52; 95% confidence interval [CI] 1.16-1.99) compared to normal kidney function. A significantly increased presence of heterogeneous plaque was observed in relation to decreased kidney function ( P for trend = .011), that is, even a mild kidney dysfunction was a potential independent risk factor for heterogeneous plaque (OR 1.43; 95% CI 1.04-1.98). Mild kidney dysfunction may be a predictor of early or accelerated carotid atherosclerosis in older adults.

Impact of cystatin-C level on the prevalence and angiographic characteristics of vasospastic angina in Korean patients

Cystatin-C, a marker of mild renal dysfunction, has been reported to be associated with cardiovascular diseases including vasospastic angina (VSA). We aimed to investigate the impact of cystatin-C level on the prevalence and angiographic characteristics of VSA in Korean patients.A total of 549 patients in the VA-KOREA (Vasospastic Angina in KOREA) registry who underwent ergonovine provocation tests were consecutively enrolled. Estimated glomerular filtration rate (eGFR) and levels of serum creatinine (Cr) and cystatin-C were assessed before angiography.The patients were classified into two groups: the VSA group (n = 149, 27.1%) and the non-VSA group (n = 400). Although eGFR and Cr levels were similar between the two groups, the VSA group had a significantly higher level of cystatin-C (P < 0.05). A high level of cystatin-C (second tertile, hazard ratio 1.432; 95% confidence interval [1.1491.805]; P = 0.026, third tertile, 1.947 [1.132-2.719]; P = 0.003) and current smoking (2.710 [1.415-4.098]; P < 0.001) were independently associated with the prevalence of VSA. Furthermore, the highest level of cystatin-C (> 0.96 ng/mL) had a significant impact on the incidence of multivessel spasm (2.608 [1.061-4.596]; P = 0.037).A high level of cystatin-C was independently associated with the prevalence of VSA and with a high-risk type of VSA in Korean patients, suggesting that proactive investigation of VSA should be considered for patients with mild renal dysfunction indicated by elevated cystatin-C.

Subclinical carotid atherosclerosis and triglycerides predict the incidence of chronic kidney disease in the Japanese general population: results from the Kyushu and Okinawa Population Study (KOPS)

OBJECTIVE

To examine whether or not subclinical atherosclerosis independently predicts the incidence of chronic kidney disease (CKD) in the Japanese general population.

METHODS

This study is part of the Kyushu and Okinawa Population Study (KOPS), a survey of vascular events associated with lifestyle-related diseases. Participants who attended both baseline (2004-2007) and follow-up (2009-2012) examinations were eligible. The common carotid intima-media thickness (IMT) was assessed for each participant at baseline. The end point was the incidence of CKD, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) during the follow-up of participants without CKD at baseline.

RESULTS

During the five-year follow-up, 224 of the 1824 participants (12.3%) who developed CKD had higher carotid IMT (0.74 ± 0.22 vs. 0.65 ± 0.14 mm, P < 0.001), higher triglycerides (1.6 ± 0.8 vs. 1.3 ± 0.7 mmol/L, P < 0.001), and lower high density lipoprotein cholesterol (1.5 ± 0.4 vs. 1.6 ± 0.4 mmol/L, P < 0.001) at baseline than those who did not. In logistic regression analysis adjusted for significant covariates, eGFR (Odds ratio [OR] 0.83, 95% confidence interval (CI) 0.80-0.85, P < 0.001), carotid IMT (0.10 mm increase: OR 1.17, 95% CI 1.04-1.33, P = 0.010), and triglycerides (OR 1.35, 95% CI 1.06-1.73, P = 0.015) at baseline were independent predictors for the development of CKD.

CONCLUSIONS

Higher carotid IMT and hypertriglyceridemia were independently associated with the development of CKD in the population studied.

The aging kidney revisited: a systematic review

As for the whole human body, the kidney undergoes age-related changes which translate in an inexorable and progressive decline in renal function. Renal aging is a multifactorial process where gender, race and genetic background and several key-mediators such as chronic inflammation, oxidative stress, the renin-angiotensin-aldosterone (RAAS) system, impairment in kidney repair capacities and background cardiovascular disease play a significant role. Features of the aging kidney include macroscopic and microscopic changes and important functional adaptations, none of which is pathognomonic of aging. The assessment of renal function in the framework of aging is problematic and the question whether renal aging should be considered as a physiological or pathological process remains a much debated issue. Although promising dietary and pharmacological approaches have been tested to retard aging processes or renal function decline in the elderly, proper lifestyle modifications, as those applicable to the general population, currently represent the most plausible approach to maintain kidney health.

How to understand the association between cystatin C levels and cardiovascular disease: Imbalance, counterbalance, or consequence?

The association of cystatin C with renal function has been studied for more than 25 years. Cystatin C has been described to have a better diagnostic performance than creatinine to assess renal function, particularly to detect small reductions in glomerular filtration rate. Recently, cystatin C has emerged as a strong predictor of incident or recurrent cardiovascular events and adverse outcomes in patients without kidney disease. Furthermore, it has been suggested that cystatin C concentrations are directly related to both inflammation and atherosclerosis. Nevertheless, the link between inflammation, atherogenesis, cardiovascular risk, and cystatin C is still poorly understood. This brief report discusses recent data, contrasting findings and possible mechanisms involved in this interaction.

Association between cystatin C and arteriosclerosis in the absence of chronic kidney disease

AIM

Chronic kidney disease (CKD) is a known risk factor for cardiovascular disease (CVD). Cystatin C was recently reported to be an endogenous surrogate of kidney function, and a high level of cystatin C is reported to be a strong predictor of CVD; however, the association between cystatin C and arteriosclerosis in a non-CKD population is unclear. This study aimed to clarify the association between cystatin C and arteriosclerosis in a non-CKD population.

METHODS

Of the 637 Japanese adults (264 men, 373 women) enrolled, we analyzed 446 participants with an estimated glomerular filtration rate (eGFR) >60 mL/min and no proteinuria (177 men, 269 women) without a history of CVD. Kidney function was evaluated according to serum cystatin C levels and eGFR. Arteriosclerosis was evaluated on the basis of the cardio-ankle vascular index (CAVI) and carotid intima-media thickness (CIMT).

RESULTS

The mean age of our subjects was 67.0±10.0 years. No variables showed any significant differences according to gender. The results of multiple linear regression analysis showed a significant correlation between serum cystatin C and CAVI only in women, but not CIMT.

CONCLUSION

We observed a significant correlation between cystatin C and CAVI, which is a marker of early-stage arteriosclerosis, in women in a non-CKD population with no proteinuria and eGFR>60 mL/min.

Mild renal dysfunction and metabolites tied to low HDL cholesterol are associated with monocytosis and atherosclerosis

BACKGROUND

The number of circulating blood monocytes impacts atherosclerotic lesion size, and in mouse models, elevated levels of high-density lipoprotein cholesterol suppress blood monocyte counts and atherosclerosis. We hypothesized that individuals with mild renal dysfunction at increased cardiovascular risk would have reduced high-density lipoprotein levels, high blood monocyte counts, and accelerated atherosclerosis.

METHODS AND RESULTS

To test whether mild renal dysfunction is associated with an increase in a leukocyte subpopulation rich in monocytes that has a known association with future coronary events, we divided individuals from the Malmö Diet and Cancer study (MDC) into baseline cystatin C quintiles (n=4757). Lower levels of renal function were accompanied by higher monocyte counts, and monocytes were independently associated with carotid bulb intima-media thickness cross-sectionally (P=0.02). Cystatin C levels were positively and plasma high-density lipoprotein cholesterol levels negatively associated with monocyte counts at baseline, after adjustment for traditional risk factors. Several amino acid metabolites tied to low levels of high-density lipoprotein cholesterol and insulin resistance measured in a subset of individuals (n=752) by use of liquid chromatography-mass spectrometry were independently associated with a 22% to 34% increased risk of being in the top quartile of monocytes (P<0.05).

CONCLUSIONS

A low high-density lipoprotein cholesterol, insulin resistance phenotype occurs in subjects with mild renal dysfunction and is associated with elevated monocytes and atherosclerosis. High blood monocyte counts may represent a previously unrecognized mechanism underlying the strong relationship between cystatin C and cardiovascular risk.

Age-related change in kidney function, its influencing factors, and association with asymptomatic carotid atherosclerosis in healthy individuals--a 5-year follow-up study

OBJECTIVES

To better define the longitudinal changes in renal function, to examine the associated risk factors, and to investigate whether there is an independent association of decline in renal function with presence of carotid plaque in a middle-aged and elderly healthy population.

METHODS

245 healthy individuals (98 males, 147 females) evaluated at baseline and 5 years later.

RESULTS

Over five years, estimated glomerular filtration rate (eGFR) decreased from 98.1±15.6 to 90.4±17.3mL/min/1.73m(2). There are three kinds of change in eGFR (elevated, stable and decreased) during follow-up, accounting for 14%, 29% and 57%, respectively. Multivariate analysis of cross-sectional data showed that gender, age, and serum uric acid (UA) were major factors which consistently affected eGFR at both baseline and follow-up, and that higher systolic blood pressure (SBP) and presence of plaque were involved in lower eGFR at the follow-up point. In longitudinal analysis, five baseline factors - age, SBP, low-density lipoprotein cholesterol (LDL-C), serum transferrin (TRF) and eGFR - independently predicted a greater variability in renal function. In addition, presence of plaque was an independent risk factor for a faster decline of eGFR.

CONCLUSIONS

Cross-sectional analysis demonstrates that renal function declines with increasing age. However, 43% of participants did not experience a decline in eGFR during follow-up. Besides older age and higher initial eGFR, presence of atherosclerotic carotid plaque, higher SBP, higher LDL-C and lower TRF are independent risk factors to predict a rapid decline of renal function in the healthy Chinese population.

Association between kidney and cardiac diastolic function in Chinese subjects without overt disease: correlation with ageing and inflammatory markers

BACKGROUND

Age-related changes in kidney structure and function have been well documented. This study aimed to assess the relationship between declines of normal ageing-related kidney function and cardiac diastolic function in a healthy Chinese population.

MATERIALS AND METHODS

A total of 852 healthy adults aged 30-98 years were enrolled and divided into four groups according to quartiles of estimated glomerular filtration rate (eGFR) and cystatin C (CYSC). Cardiac diastolic function was measured by ratio of peak velocity of early filling to peak velocity of atrial filling (E/A), which was derived by B-mode echocardiography. Lower E/A was defined as measures under the 25th percentile of sample distribution (0·784).

RESULTS

Age was significantly associated with eGFR (r = -0·102, P < 0·01), CYSC (r = 0·544, P < 0·01) and E/A (r = -0·381, P < 0·01). Binary logistic regression analysis revealed that second, third and fourth quartile groups of CYSC and fourth quartile of eGFR were significantly associated with lower E/A in an unadjusted model. However, these associations were lost after full adjustment.

CONCLUSIONS

Our results confirm that ageing is a major factor contributing to declines in both kidney and cardiac diastolic function in a healthy population. Adjustment for covariates, however, showed that normal ageing-related declines in kidney function and cardiac diastolic function are not independently linked.