Cardiovascular Outcomes and All-Cause Mortality: Exploring the Interaction Between CKD and Cardiovascular Disease

Atherosclerosis in CKD: differences from the general population

The prevalence of cardiovascular morbidity and mortality is higher in patients with chronic kidney disease (CKD)-especially those with end-stage renal disease-than in the general population. The contribution of atherosclerosis to cardiovascular disease in patients with CKD remains unclear. Researchers in the 1970s proposed that atherosclerosis was the main cause of cardiovascular disease in patients with CKD and that its progression, based on observations of patients on long-term dialysis, was accelerated by the uremic state. Subsequent reports, however, favor the involvement of other mechanisms, such as arteriosclerosis (characterized by vascular stiffening), vascular calcification, 'myocyte/capillary mismatch', congestive cardiomyopathy, and sudden cardiac death. Imaging and morphological studies have contributed to our understanding of the pathogenesis and progression of cardiovascular disease associated with CKD. Based on clinical and experimental findings, we hypothesize the following: the initial cardiovascular abnormalities in the CKD setting include arteriosclerosis, left ventricular diastolic dysfunction, and left ventricular hypertrophy, abnormalities which, in adult patients, are often accompanied by atherosclerosis. The prevalence of atherosclerosis increases with age and is aggravated, but not specifically induced, by CKD. The cardiovascular events associated with atherosclerosis are more often fatal in patients with CKD than in individuals without CKD.

Serum levels of matrix metalloproteinase-10 are associated with the severity of atherosclerosis in patients with chronic kidney disease

Cardiovascular disease is the leading cause of mortality in chronic kidney disease (CKD). As matrix metalloproteinases have a major role in atherosclerosis, we hypothesized that alterations in metalloproteinases-8, -10 and their tissue inhibitor-1 can be associated with the severity of atherosclerosis in patients with kidney disease. This was evaluated in a cross-sectional, observational study of 111 patients with stages I-V kidney disease, 217 patients on dialysis and 50 healthy controls. The severity of atherosclerosis was estimated with the atherosclerosis score (AS), combining the results of ankle-brachial index and carotid ultrasound. Serum levels of the two metalloproteinases and tissue inhibitor-1 were measured by enzyme-linked immunosorbent assay and were significantly increased in patients with kidney disease compared with the healthy controls, and higher in patients on dialysis than in earlier stages of CKD. The severity of the AS was also more prevalent in the dialysis group, in which serum levels of both metalloproteinases and tissue inhibitor-1 were significantly higher. After multivariate analysis, metalloproteinase-10, dialysis, C-reactive protein, age, and male gender were associated with increased risk of atherosclerosis. Thus, patients with CKD exhibit elevated levels of circulating metalloproteinase-10, and this was independently associated with the severity of atherosclerosis and may represent a new biomarker of atherosclerotic diseases.

Surgical management of bilateral synchronous kidney tumors: functional and oncological outcomes

PURPOSE

We evaluated renal functional and oncological outcomes after sequential partial nephrectomy and radical nephrectomy in patients with bilateral synchronous kidney tumors.

MATERIALS AND METHODS

A total of 220 patients treated from June 1994 to July 2008 were included in the study. Estimated glomerular filtration rate, and overall, cancer specific and recurrence-free survival were assessed.

RESULTS

Patients underwent sequential partial nephrectomy (134), partial nephrectomy followed by radical nephrectomy (60) or radical nephrectomy followed by partial nephrectomy (26). Final estimated glomerular filtration rate after bilateral surgery was 59, 36 and 35 ml/minute/1.73 m(2) in these 3 groups, respectively (p <0.001). The order in which partial nephrectomy and radical nephrectomy were conducted did not affect functional outcomes. Overall survival of patients with bilateral cancer was 86% at 5 years and 71% at 10 years, cancer specific survival was 96% at 5 and 10 years, and recurrence-free survival was 73% at 5 years and 44% at 10 years. Overall survival was decreased in patients with tumors larger than 7 cm (p = 0.003). Patients with postoperative stage III or greater chronic kidney disease had decreased overall survival due to noncancer causes (p = 0.007).

CONCLUSIONS

Patients treated with sequential surgery for bilateral synchronous kidney tumors have 5 and 10-year oncological outcomes comparable to those of patients with unilateral kidney cancer. Decreased overall survival was significantly associated with tumor size larger than 7 cm and postoperative stage III or greater chronic kidney disease. Nephron sparing surgery should be conducted for all amenable bilateral kidney masses given the negative impact of renal functional decline on overall survival.

Long-term management of bilateral, multifocal, recurrent renal carcinoma

Patients with bilateral multifocal renal cell carcinoma are at increased risk of developing locally recurrent or de novo tumors after nephron-sparing procedures. When dealing with recurrent renal masses the options are limited to observation, total nephrectomy, ablation, or repeat surgical intervention. The main reason for recurrence after nephron-sparing surgery is likely to be the presence of multifocal disease, which is identified in 4.3-25.0% of radical nephrectomy specimen. Bilateral renal involvement is seen in almost 90% of cases of multifocal renal carcinoma, and conversely the majority of patients with bilateral disease will have multifocal tumors. Many patients who are treated for multifocal disease, therefore, require subsequent surgical interventions. The outcome data for repeat renal interventions demonstrate reasonable functional and oncologic outcomes despite higher rates of perioperative complications. Our own results support the use of reoperative renal surgery rather than total nephrectomy and renal replacement therapy.

Warfarin dosing in patients with impaired kidney function

BACKGROUND

In patients with kidney impairment, warfarin, a drug metabolized primarily by the cytochrome P-450 system, is initiated at similar doses and managed similarly as in the general medical population. Unfortunately, few data exist to guide dose adjustment in patients with decreased kidney function. Here, we determine the degree of warfarin dose reduction associated with kidney impairment and make recommendations for warfarin dosing.

STUDY DESIGN

Cross-sectional analysis.

SETTING & PARTICIPANTS

Long-term warfarin users followed up at anticoagulation clinics (n = 980); 708 participants from the University of Alabama (UAB) and 272 participants from the University of Chicago (UIC).

PREDICTOR

No/mild (estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73 m(2)), moderate (eGFR, 30-59 mL/min/1.73 m(2)), and severe (eGFR < 30 mL/min/1.73 m(2)) kidney impairment; CYP2C9 and VKORC1 genotype; age; race; sex; body mass; sociodemographic factors; smoking status; alcohol; vitamin K intake; comorbid conditions (eg, congestive heart failure); and drug interactions (eg, amiodarone and statins).

OUTCOME & MEASUREMENT

Warfarin dose (milligrams per day) was evaluated using linear regression after adjustment for clinical, demographic, and genetic factors.

RESULTS

Prevalences of moderate (31.8% and 27.6%) and severe kidney impairment (8.9% and 6.6%) were similar in the UAB and UIC cohorts. Warfarin dose requirements were significantly lower in patients with moderate and severe kidney impairment compared with those with no/mild kidney impairment in the UAB (P < 0.001) and UIC (P < 0.001) cohorts. Compared with patients with no/mild kidney impairment, patients with moderate kidney impairment required 9.5% lower doses (P < 0.001) and patients with severe kidney impairment required 19% lower doses (P < 0.001).

LIMITATIONS

No measurement of warfarin, serum albumin, vitamin K, and coagulation factors; no evaluation of other markers (eg, cystatin).

CONCLUSION

Moderate and severe kidney impairment were associated with a reduction in warfarin dose requirements.

Kidney function, albuminuria, and all-cause mortality in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study

BACKGROUND

Chronic kidney disease and albuminuria are associated with increased risk of all-cause mortality.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

17,393 participants (mean age, 64.3 ± 9.6 years) in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study.

PREDICTOR

Estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (ACR).

OUTCOME

All-cause mortality (710 deaths); median duration of follow-up, 3.6 years. MEASUREMENTS & ANALYSIS: Categories of eGFR (90 to <120, 60 to <90, 45 to <60, 30 to <45, and 15 to <30 mL/min/1.73 m(2)) and urinary ACR (<10 mg/g or normal, 10 to <30 mg/g or high normal, 30 to 300 mg/g or high, and >300 mg/g or very high). Cox proportional hazards models were adjusted for demographic factors, cardiovascular covariates, and hemoglobin level.

RESULTS

The background all-cause mortality rate for participants with normal ACR, eGFR of 90 to <120 mL/min/1.73 m(2), and no coronary heart disease was 4.3 deaths/1,000 person-years. Higher ACR was associated with an increased multivariable-adjusted HR for all-cause mortality within each eGFR category. Decreased eGFR was associated with a higher adjusted HR for all-cause mortality for participants with high-normal (P = 0.01) and high (P < 0.001) ACRs, but not those with normal or very high ACRs.

LIMITATIONS

Only 1 laboratory assessment for serum creatinine and ACR was available.

CONCLUSIONS

Increased albuminuria was an independent risk factor for all-cause mortality. Decreased eGFR was associated with increased mortality risk in those with high-normal and high ACRs. The mortality rate was low in the normal-ACR group and increased in the very-high-ACR group, but did not vary with eGFR in these groups.

[Indications for parathyroidectomy in renal hyperparathyroidism: comments on the significance of new therapeutics]

New therapeutics for the treatment of chronic kidney disease and secondary hyperparathyroidism, such as calcium and aluminium-free phosphate binders, calcimimetic agents and active vitamin D metabolites may decrease the need for parathyroidectomy. The calcimimetic cinacalcet does not induce a longer lasting regression of renal hyperparathyroidism and autonomous growing of parathyroids and the therapeutic effect is limited to the period of treatment. The classical indications for surgery, hypercalcemia, vascular calcification, severe osteopathy, drug-resistant hyperphosphatemia and calciphylaxis are still valid if patients do not respond to medical therapy under the condition that adynamic bone disease is excluded. Individual operative risk factors and improvement of quality of life are important supplementary factors for the indication for parathyroidectomy.

Methods and potential biomarkers for the evaluation of endothelial dysfunction in chronic kidney disease: a critical approach

The impressive cardiovascular morbidity and mortality of chronic kidney disease (CKD) patients is attributable in a significant proportion to endothelial dysfunction (ED), arterial stiffness, and vascular calcifications. Abnormal vascular reactivity in these patients is more pronounced compared with other high-risk populations, but remains undiagnosed in the usual clinical setting. We briefly review the most important causes and risk factors of ED, oxidative stress, and inflammation related to arterial stiffness. We describe the main methods of ED investigation and the importance of using potential biomarkers together with classic techniques for a more comprehensive assessment of this condition. These methods include evaluation of: forearm blood flow by plethysmography, skin microcirculation by laser Doppler, and flow-mediated vasodilation by Doppler ultrasound imaging. Applanation tonometry is an easy-to-handle tool that allows a clinically reliable assessment of arterial stiffness and is also useful in quantifying endothelium-dependent and -independent vascular reactivity. We also discuss the diagnostic and therapeutic impact of new markers of ED in the CKD population. Improvement of endothelial function is an important challenge for clinical practice, and there are relatively few therapeutical strategies available. Therefore, a combined biomarker and bedside investigational approach could be a starting point for developing optimal therapeutic tools.

Chronic kidney disease and end-stage renal disease in the elderly population: current prevalence, future projections, and clinical significance

The world's population is aging, with the number of older adults projected to increase dramatically over the next 2 decades. This trend poses major challenges to health care systems, reflecting the greater health care use and more comorbid conditions among elderly adults. Chronic kidney disease (CKD) is a substantial concern in the elderly population, with both an increasing incidence of treated kidney failure with dialysis as well as a high prevalence of earlier stages of CKD. Given the high burden of risk factors for CKD, the high prevalence of CKD in the elderly population is not surprising, with the rise in obesity, diabetes, and hypertension in middle-aged adults likely foreshadowing further increases in CKD prevalence among the elderly population. It is now commonly agreed that the presence of CKD identifies a higher risk state in the elderly population, with increased risk for multiple adverse outcomes, including kidney failure, cardiovascular disease, cognitive impairment, and death. Accordingly, CKD in older adults is worthy of attention by both health care providers and patients, with the presence of a reduced glomerular filtration rate or albuminuria in the elderly potentially informing therapeutic and diagnostic decisions for these individuals.

Therapeutic potential of endothelin receptor antagonists for chronic proteinuric renal disease in humans

Diabetes and arterial hypertension continue to be the main causes of chronic renal failure in 2010, with a rising prevalence in part due to the worldwide obesity epidemic. Proteinuria is a main feature of chronic renal disease and mediated by defects in the glomerular filtration barrier and is as a good predictor of cardiovascular events. Indeed, chronic renal disease due to glomerulosclerosis is one of the important risk factors for the development of coronary artery disease and stroke. Glomerulosclerosis develops in response to inflammatory activation and increased growth factor production. Preclinical and first preliminary clinical studies provide strong evidence that endogenous endothelin-1 (ET-1), a 21-amino-acid peptide with strong growth-promoting and vasoconstricting properties, plays a central role in the pathogenesis of proteinuria and glomerulosclerosis via activation of its ET(A) subtype receptor involving podocyte injury. These studies have not only shown that endothelin participates in the disease processes of hypertension and glomerulosclerosis but also that features of chronic renal disease such as proteinuria and glomerulosclerosis are reversible processes. Remarkably, the protective effects of endothelin receptors antagonists (ERAs) are present even on top of concomitant treatments with inhibitors of the renin-angiotensin system. This review discusses current evidence for a role of endothelin for proteinuric renal disease and podocyte injury in diabetes and arterial hypertension and reviews the current status of endothelin receptor antagonists as a potential new treatment option in renal medicine.

Prognostic value of chronic kidney disease in patients with coronary heart disease: role of estimating equations

OBJECTIVE

Chronic kidney disease (CKD) increases risk of coronary heart disease (CHD), but the impact of using different equations for estimating kidney function on CHD is not clear yet. This study described the prognostic value of CKD as defined by various creatinine- (Cr-eGFR) and cystatin C-based estimating (Cys-eGFR) equations and their combinations on subsequent cardiovascular disease (CVD) events in patients with CHD.

DESIGN

Cohort study.

SETTING

Patients with coronary heart disease in in-patient rehabilitation and long-term follow-up (mean 63.4 months).

SUBJECTS

1050 patients with coronary heart disease aged 30-70 years at baseline.

METHODS

CKD was defined as eGFR<60 mL/min/1.73 m2 (CKD stages 3-5) estimated by three Cr-eGFR equations (Cockroft-Gault equation adjusted for body surface area (CG/BSA), Modification of Diet in Renal Disease Study (MDRD) equation, CKD-EPIcrea) and by two Cys-eGFR equations (Arnal-Dade equation, CKD-EPIcys) and a combination. The primary endpoint of our study was subsequent CVD events.

RESULTS

During follow-up 118 patients (11.2%) experienced the outcome of our study. CKD assessed by the CG/BSA, MDRD, and CKD-EPIcrea equations showed no statistically significant association with subsequent CVD events after adjustment for multiple covariates (hazard ratio (HR) 1.45 [95% CI, 0.81-2.59], HR 1.47 [95% CI, 0.84-2.60], and HR 1.31 [95% CI, 0.72-2.83], respectively). By contrast, the Cys-eGFR equations were much stronger associated with subsequent CVD endpoints (Arnal-Dade: HR, 2.01 [95% CI, 1.34-3.04]; CKD-EPIcys HR, 2.22 [95% CI, 1.46-3.37]). The CKD-EPIcys also provided the highest area under the curve value.

CONCLUSION

Our study shows that prevalent CKD is an independent risk factor for subsequent CVD in patients with prevalent CHD and implies that Cys-eGFR equations show a better clinical utility compared to the Cr-eGFR equations.

Brachial-ankle pulse wave velocity predicts silent cerebrovascular diseases in patients with end-stage renal diseases

AIM

Cerebrovascular disease (CVD) is a major determinant of the prognosis in end-stage renal diseases (ESRD). The purpose of this study was to examine whether factors associated with arterial stiffness contributed to the development of CVD in patients with ESRD.

METHODS

CVD (lacunes and carotid/intracranial artery stenosis) was evaluated with brain magnetic resonance imaging (MRI), and carotid/intracranial artery magnetic resonance angiography (MRA) in 44 pre-dialytic patients. The severity of CVD was evaluated by the number of lacunes and the degree of stenosis, respectively. The association between CVD and atherosclerotic parameters was evaluated.

RESULTS

Patients with severe lacunes (n=18) manifested older age, lower diastolic blood pressure, serum creatinine and albumin, and higher CRP and serum calcium than those with absent-moderate lacunes (n=26). When assessed by multivariate analysis, only baPWV was adopted as an independent risk factor for severe lacunes. Furthermore, baPWV and i-PTH were associated with the severity of carotid/intracranial artery stenosis, both of which were independent of other risk factors, including age and diabetes.

CONCLUSIONS

Arterial stiffness may constitute a novel determinant predicting the severity of CVD in pre-dialytic patients besides classical risk factors.

Endotoxemia is associated with better clinical outcome in incident Chinese peritoneal dialysis patients: a prospective cohort study

BACKGROUND

Endotoxemia is common in peritoneal dialysis (PD) patients; circulating lipopolysaccharide (LPS) level is related to the degree of systemic inflammation and atherosclerosis. We examine whether baseline plasma LPS level represents a prognostic marker in new PD patients.

METHODS

We studied 158 new Chinese PD patients (80 males). Baseline plasma LPS level at initiation of PD was measured. Patients were stratified into quartiles according to plasma LPS level: quartile I, <0.45 EU/mL; II, 0.45 - <0.70 EU/mL; III, 0.70 - <0.95 EU/mL; and IV, ≥ 0.95 EU/mL. The patients were then prospectively followed for the development of cardiovascular events. All-cause mortality and duration of hospitalization were also recorded.

RESULTS

Average age was 55.6 +/- 14.7 years; average endotoxin concentration was 0.70 +/- 0.30 EU/mL; average follow-up was 55.5 +/- 36.9 months. At 60 months, event-free survival was 41.0%, 52.5%, 65.0%, and 61.5% for LPS level quartiles I, II, III, and IV, respectively (log rank test p = 0.066). By multivariate analysis with the Cox proportional hazard model to adjust for confounders, plasma LPS level had no independent effect. At 60 months, technique survival was 20.5%, 20.0%, 32.5%, and 51.3% for LPS level quartiles I, II, III, and IV, respectively (log rank test p = 0.0009). By Cox proportional hazard model, each higher quartile of LPS conferred 28.6% protection (95% confidence interval 15.6% - 40.3%, p = 0.0002) from developing technique failure. A higher plasma LPS level had a lower all-cause mortality (unadjusted hazard ratio 0.486, p = 0.046) and cardiovascular mortality (unadjusted hazard ratio 0.251, p = 0.025), but the result became insignificant after adjusting for potential confounders.

CONCLUSION

A higher baseline plasma LPS level is an independent predictor of better technique survival in new Chinese PD patients, with an insignificant trend of fewer cardiovascular events. The observation seems to conform to the phenomenon of reverse epidemiology for other traditional cardiovascular risk factors in dialysis patients but the exact reason for this paradoxical phenomenon requires further investigation.

CKD classification based on estimated GFR over three years and subsequent cardiac and mortality outcomes: a cohort study

Background

It is unknown whether defining chronic kidney disease (CKD) based on one versus two estimated glomerular filtration rate (eGFR) assessments changes the prognostic importance of reduced eGFR in a community-based population.

Methods

Participants in the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study were classified into 4 groups based on two eGFR assessments separated by 35.3 ± 2.5 months: sustained eGFR < 60 mL/min per 1.73 m² (1 mL/sec per 1.73 m²); eGFR increase (change from below to above 60); eGFR decline (change from above to below 60); and eGFR persistently ≥60. Outcomes assessed in stratified multivariable Cox models included cardiac events and a composite of cardiac events, stroke, and mortality.

Results

There were 891 (4.9%) participants with sustained eGFR < 60, 278 (1.5%) with eGFR increase, 972 (5.4%) with eGFR decline, and 15,925 (88.2%) with sustained eGFR > 60. Participants with eGFR sustained < 60 were at highest risk of cardiac and composite events [HR = 1.38 (1.15, 1.65) and 1.58 (1.41, 1.77)], respectively, followed by eGFR decline [HR = 1.20 (1.00, 1.45) and 1.32 (1.17, 1.49)]. Individuals with eGFR increase trended toward increased cardiac risk [HR = 1.25 (0.88, 1.77)] and did not significantly differ from eGFR decline for any outcome. Results were similar when estimating GFR with the CKD-EPI equation.

Conclusion

Individuals with persistently reduced eGFR are at highest risk of cardiovascular outcomes and mortality, while individuals with an eGFR < 60 mL/min per 1.73 m² at any time are at intermediate risk. Use of even a single measurement of eGFR to classify CKD in a community population appears to have prognostic value.

Synergistic effects of asymmetrical dimethyl-L-arginine accumulation and endothelial progenitor cell deficiency on renal function decline during a 2-year follow-up in stable angina

BACKGROUND

Renal insufficiency predisposes to coronary artery disease (CAD), but also CAD and traditional risk factors accelerate renal function loss. Endothelial progenitor cell (EPC) deficiency and elevated asymmetrical dimethyl-L-arginine (ADMA), an endogenous nitric oxide (NO) formation inhibitor, predict adverse CAD outcome. Our aim was to assess changes in estimated glomerular filtration rate over time (DeltaeGFR) in relation to baseline EPC blood counts and ADMA levels in stable angina.

METHODS

Eighty non-diabetic men with stable angina were followed up for 2 years after elective coronary angioplasty. Exclusion criteria included heart failure, left ventricular systolic dysfunction, eGFR <30 ml/min/1.73 m(2) and coexistent diseases. Those with cardiovascular events or ejection fraction <55% during the follow-up were also excluded. A baseline blood count of CD34+/kinase-insert domain receptor (KDR)+ cells, a leukocyte subpopulation enriched for EPC, was quantified by flow cytometry (percentage of lymphocytes).

RESULTS

A synergistic interaction (P = 0.015) between decreased CD34+/KDR+ cell counts and increased plasma ADMA, but not symmetrical dimethyl-L-arginine, was the sole significant multivariate DeltaeGFR predictor irrespective of baseline eGFR. DeltaeGFR was depressed in the simultaneous presence of high ADMA (>0.45 micromol/l, median) and low CD34+/KDR+ cell counts (<0.035%, median) compared to either of the other subgroups (P = 0.001-0.01). DeltaeGFR did not correlate with traditional risk factors, angiographic CAD extent, levels of C-reactive protein and soluble vascular cell adhesion molecule-1.

CONCLUSIONS

Elevated ADMA and EPC deficiency may synergistically contribute to accelerated renal function decline in stable angina. This could result from the impairment of the EPC-dependent endothelial renewal in the kidney, an NO-dependent process.

Renal dysfunction potentiates foam cell formation by repressing ABCA1

OBJECTIVE

Patients with chronic kidney disease (CKD) have the highest risk for atherosclerotic cardiovascular disease (CVD). Current interventions have been insufficiently effective in lessening excess incidence and mortality from CVD in CKD patients versus other high-risk groups. The mechanisms underlying the heightened risk remain obscure but may relate to differences in CKD-induced atherogenesis, including perturbation of macrophage cholesterol trafficking.

METHODS AND RESULTS

We examined the impact of renal dysfunction on macrophage cholesterol homeostasis in the apoE(-/-) mouse model of atherosclerosis. Renal impairment induced by uninephrectomy dramatically increased macrophage cholesterol content, linked to striking impairment of macrophage cholesterol efflux. This blunted efflux was associated with downregulation of the cholesterol transporter ATP-binding cassette transporter A1 (ABCA1) and activation of the nuclear factor-kappa B (NF-kappaB). Treatment with the angiotensin receptor blocker (ARB) losartan decreased NF-kappaB and restored cholesterol efflux.

CONCLUSIONS

Our findings show that mild renal dysfunction perturbs macrophage lipid homeostasis by inhibiting cholesterol efflux, mediated by decreased ABCA1 transporter and activation of NF-kappaB, and that ARB can restore cholesterol efflux.

Cystatin C: a better marker to detect coronary artery sclerosis

BACKGROUND

Nowadays, early detection and treatment can often keep chronic kidney disease patients from getting worse and prevent the occurrence of cardiovascular disease. Cystatin C (Cys-C) is a new marker for renal dysfunction. This study investigated whether Cys-C played an important role for screening coronary artery disease.

METHODS

The consecutive 88 outpatients (51 males and 37 females), who were suspected of having effort angina pectoris or asymptomatic ischemic heart disease, were enrolled. Serum Cys-C, which was obtained within 3 months before coronary angiography, was assessed with the presence or absence of coronary arteriosclerosis, the number of culprit arteries, and blood biochemical parameters.

RESULTS

Mean serum Cys-C was 0.82+/-0.29 mg/l. Significant differences in the estimated creatinine clearance (p=0.036), hemoglobin A1c (p=0.01), left ventricular ejection fraction (p=0.01), creatinine (p=0.007), Cys-C (p=0.006), and high-density lipoprotein (HDL) cholesterol (p=0.001) were observed between the patients with or without coronary arteriosclerosis. Serum Cys-C was significantly greater in the multi-vessel disease (MVD) group than the 0 vessel disease (0VD) group (p<0.001). HDL cholesterol was significantly lower in the MVD group than the 0VD and single-vessel disease groups (p=0.002 and p=0.005, respectively).

CONCLUSION

The results of this study suggest Cys-C might be one of the risk factors for coronary arteriosclerosis in the patients with suspected ischemic heart disease without any history of coronary artery disease. Cys-C was a useful marker to detect coronary artery disease and the level of Cys-C could reflect the severity of coronary arteriosclerosis.

Public health consequences of chronic kidney disease

With its rising incidence and prevalence, chronic kidney disease (CKD) is a major public health concern, both in the United States and worldwide. Recent worldwide initiatives have attempted to garner attention for CKD by emphasizing that the condition is "common, harmful, and treatable." In the United States, as many as 26 million adults may have CKD, an increase from approximately 10% of the US adult population between 1988 and 1994 to >13% just one decade later. Similar rates have been seen worldwide, with a CKD prevalence of 13% in Beijing, China and 16% in Australia. In the United States, the dramatic rise in the prevalence of CKD likely reflects similar increases in obesity and its sequelae-namely, diabetes, hypertension, and cardiovascular disease. The prevalence of CKD, as well as its associated costs, is expected to continue to increase.

Chronic kidney disease is associated with incident cognitive impairment in the elderly: the INVADE study

BACKGROUND

Limited data exist regarding the relationship between decreased renal function and cognitive impairment.

METHODS

A total of 3679 participants of the Intervention Project on Cerebrovascular Diseases and Dementia in the Community of Ebersberg (INVADE) composed the community-based cohort study. Measures of renal function were estimated using the Cockcroft-Gault equation and divided into normal, mild and moderate-to-severe impaired renal function (creatinine clearance >or=60, 45-59 and <45 mL/min/1.73 m(2), respectively). The main outcome measures were cognitive impairment at baseline and new cognitive impairment after a 2-year follow-up. Cognitive function was measured using the 6-Item Cognitive Impairment Test (6CIT). Multiple logistic regression analysis was used to assess the association between renal function and cognitive impairment.

RESULTS

At baseline, 396 participants (10.8%) had cognitive impairment. After the 2-year follow-up, 194 participants (6.2%) developed new cognitive impairment. The incidence of cognitive impairment across the groups with normal renal function, mild and moderate-to-severe kidney disease at baseline were 5.8, 9.9 and 21.5%, respectively. Multiple logistic regression analysis after adjustment for possible confounders including traditional cardiovascular risk factors showed a significant association for participants with moderate-to-severe kidney disease at baseline to develop new cognitive impairment after the 2-year follow-up [odds ratio: 2.14 (95% confidence interval: 1.18-3.87), P = 0.01].

CONCLUSIONS

In summary, moderate-to-severe impaired renal function is associated with incident cognitive impairment after 2 years in a large cohort of elderly subjects.

The use of vitamin D analogues in chronic kidney diseases: possible mechanisms beyond bone and mineral metabolism

Chronic kidney disease (CKD) is a common and costly medical condition, and currently available therapeutic options remain unsatisfactory. Vitamin D analogues are widely used for the bone and mineral disorder associated with CKD. However, accumulating evidence suggests that vitamin D analogues may have actions other than their effects on bone and mineral metabolism. In this article, we review the following aspects on the use of vitamin D analogues for the treatment of CKD: (1) epidemiological studies showing that patients with late-stage CKD have better survival than untreated patients; (2) animal studies showing that vitamin D analogues may retard the progression of CKD; (3) human studies on the anti-proteinuric and possibly renal protecting effects of vitamin D analogues in CKD and (4) the potential mechanisms of its therapeutic benefit. Nonetheless, definitive proof of the clinical benefits by randomized control trial would be necessary before one could advocate the routine use of vitamin D analogues for the treatment of CKD patients.

Albuminuria, cognitive functioning, and white matter hyperintensities in homebound elders

BACKGROUND

Albuminuria, a kidney marker of microvascular disease, may herald microvascular disease elsewhere, including in the brain.

STUDY DESIGN

Cross sectional.

SETTING & PARTICIPANTS

Boston, MA, elders receiving home health services to maintain independent living who consented to brain magnetic resonance imaging.

PREDICTOR

Urine albumin-creatinine ratio (ACR).

OUTCOME

Performance on a cognitive battery assessing executive function and memory by using principal components analysis and white matter hyperintensity volume on brain imaging, evaluated in logistic and linear regression models.

RESULTS

In 335 participants, mean age was 73.4 +/- 8.1 years and 123 participants had microalbuminuria or macroalbuminuria. Each doubling of ACR was associated with worse executive function (beta = -0.05; P = 0.005 in univariate and beta = -0.07; P = 0.004 in multivariable analyses controlling for age, sex, race, education, diabetes, cardiovascular disease, hypertension, medications, and estimated glomerular filtration rate [eGFR]), but not with worse memory or working memory. Individuals with microalbuminuria or macroalbuminuria were more likely to be in the lower versus the highest tertile of executive functioning (odds ratio, 1.18; 95% confidence interval, 1.06 to 1.32; odds ratio, 1.19; 95% confidence interval, 1.05 to 1.35 per doubling of ACR in univariate and multivariable analyses, respectively). Albuminuria was associated with qualitative white matter hyperintensity grade (odds ratio, 1.13; 95% confidence interval, 1.02 to 1.25; odds ratio, 1.15; 95% confidence interval, 1.02 to 1.29 per doubling of ACR) in univariate and multivariable analyses and with quantitative white matter hyperintensity volume (beta = 0.11; P = 0.007; beta = 0.10; P = 0.01) in univariate and multivariable analyses of log-transformed data. Results were similar when excluding individuals with macroalbuminuria.

LIMITATIONS

Single measurement of ACR, indirect creatinine calibration, and reliance on participant recall for elements of medical history.

CONCLUSIONS

Albuminuria is associated with worse cognitive performance, particularly in executive functioning, as well as increased white matter hyperintensity volume. Albuminuria likely identifies greater brain microvascular disease burden.

The effect of joint exposures: examining the presence of interaction

Clinical epidemiological studies investigate whether an exposure, or risk factor, is causally related to the development or progression of a disease or mortality. It might be of interest to study whether this relation is different in different types of patients. To address such research questions, the presence of interaction among risk factors can be examined. Causal interaction between two risk factors is considered most clinically relevant in epidemiology. Causal interaction occurs when two risk factors act together in causing disease and is explicitly defined as a deviation from additivity on a risk difference scale. Statistical interaction can be evaluated on both an additive (absolute risk) and multiplicative (relative risk) scale, depending on the model that is used. When using logistic regression models, which are multiplicative models, several measures of additive interaction are presented to evaluate whether the magnitude of an association differs across subgroups: the relative excess risk due to interaction (RERI), the attributable proportion due to interaction (AP), or the synergy index (S). For a transparent presentation of interaction effects the recent Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement advises reporting the separate effect of each exposure as well as the joint effect compared with the unexposed group as a joint reference category to permit evaluation of both additive and multiplicative interaction.

Epidemiology of chronic kidney disease: results from a population of older adults in Germany

OBJECTIVE

To determine prevalences and stages of chronic kidney disease (CKD), and evaluate association of CKD with related covariables in a large population of older adults.

METHODS

This cross-sectional analysis included 9806 participants of a general health check-up aged 50-74 years in Germany. We performed multivariate analysis to identify association of CKD with related covariables. Partial spearman correlations of eGFR with related biomarkers were calculated.

RESULTS

Overall, 17.4% of subjects had CKD. Prevalences of stages 1, 2, 3, 4/5 CKD were 4.6%, 4.7%, 17.0% and 0.4%, respectively. Prevalence of CKD increased with age and peaked in age 70-74 years with 23.9%. In multivariable analysis of older age, female, self-reported history of cardiovascular diseases, diabetes and statin usage were independently associated with increased risk for CKD. Significant correlations were found between eGFR and serum cystatin C (-0.28), C-reactive protein (-0.04), fasting glucose (0.12), HbA(1c) (-0.06), total cholesterol (-0.32), and triglycerides (-0.07) after adjustment for covariates.

CONCLUSIONS

This study shows a high prevalence of CKD among older adults. It highlights the association of eGFR with history of cardiovascular diseases, glycemic markers, and cardiovascular risk factors and may point to further possible targets in early prevention of CKD.

The effects of environmental stressors on the mortality of the oldest old male population in Hong Kong, 1977-2006

Although age-sex-specific mortality rates were decreasing over the years, such a trend was not observed for the male population aged 85 or above (the oldest old) in Hong Kong. Despite literature suggesting that environmental stressors were associated with higher mortality, the adverse effects of socioeconomic and political events were seldom included. Hence, this study explored the relationship between environmental stressors covering adverse weather conditions as well as key socioeconomic and political events and fluctuations in the oldest old mortality rates in Hong Kong during the period 1977 to 2006. The oldest old mortality rates in Hong Kong were observed to have a likelihood of being associated with these environmental stressors. Furthermore, men appeared to be more susceptible to these risk factors than did women. More care and attention should be given to the oldest old men, in particular, during periods of socioeconomic or political upheavals. A cohort study would be useful to study these stressors in greater detail.

Understanding the role of genetic polymorphisms in chronic kidney disease

Although no valid studies clearly indicate increasing or decreasing numbers of incident paediatric patients, the prevalence of chronic kidney disease (CKD) and end-stage renal disease (ESRD) is growing worldwide. This is mainly due to improved access to renal replacement therapy (RRT), increased survival after dialysis and kidney transplantation and an increase in diagnosis and referral of these patients. Although the increase in CKD prevalence is mainly caused by environmental factors, genetic factors may also influence the incidence and/or the progression of CKD and its complications. As CKD patients might be more sensitive to genetic effects due to the exposure to a uraemic milieu, this makes studies of genetic factors especially interesting in this population. The goal of identifying genetic factors that contribute to the outcome of CKD is to gain further understanding of the disease pathogenesis and underlying causes and, possibly, to use this knowledge to predict disease or its complications and to identify a risk population. Therefore, genetic screening of paediatric CKD patients may enhance the impact of preventive measures that could have a positive effect on outcome. Furthermore, by identifying patients' genetic backgrounds, it is possible that a more individualised therapy could be designed.

Mortality risks for all causes and cardiovascular diseases and reduced GFR in a middle-aged working population in Taiwan

BACKGROUND

Effects of decreased estimated glomerular filtration rate (eGFR) on cardiovascular disease (CVD) mortality are uncertain in Chinese general populations.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

17,026 adults 50 years and older in Taiwan. A subset of 7,968 had repeated measurements.

PREDICTOR

Decreased eGFR and its progression. eGFR was calculated from serum creatinine level by using the Modification of Diet in Renal Disease Study equation.

OUTCOMES

Mortality from all causes and CVD, including coronary heart disease (CHD) and stroke, from the National Death Registry.

MEASUREMENTS

Hazard ratios (HRs) and Kaplan-Meier survival curves were calculated for participants with a moderate to severe decrease in eGFR (<60 mL/min/1.73 m(2)) compared with those with normal eGFR (> or =90 mL/min/1.73 m(2)). HR of a rapid decrease (> or =20%) in eGFR was also calculated.

RESULTS

Mean age of all participants was 57.2 +/- 5.2 (SD) years. We observed 1,682 deaths in 15 years of follow-up. Participants with a moderate to severe decrease in eGFR had increased HRs for mortality from all causes (1.44; 95% confidence interval [CI], 1.22 to 1.70), CVD (1.90; 95% CI, 1.36 to 2.65), CHD (2.07; 95% CI, 1.26 to 3.41), and stroke (2.16; 95% CI, 1.29 to 3.62) after adjusting for confounders. Decreased eGFR was associated with ischemic stroke, but not hemorrhagic stroke. No significant interaction between decreased eGFR and anemia, diabetes, or smoking was found. There were 660 participants with a 20% or greater decrease in eGFR from baseline during 18 months of follow-up. They had increased HRs for all causes (1.45; 95% CI, 1.13 to 1.86), CVD (2.48; 95% CI, 1.58 to 3.89), CHD (2.14; 95% CI, 1.07 to 4.29), and stroke (2.79; 95% CI, 1.45 to 5.36) compared with those with less than a 20% decrease in eGFR during the same period.

LIMITATIONS

Data for proteinuria were not available. Creatinine assay was not calibrated.

CONCLUSIONS

A moderate to severe or fast decrease in eGFR was associated with all-cause and CVD mortality in this ethnic Chinese cohort.

Relationship between silent brain infarction and chronic kidney disease

Background. The presence of silent brain infarction (SBI) increases the risk of symptomatic stroke and dementia. The association between SBI and chronic kidney disease (CKD) has not been clarified. Moreover, little is known about what factors are related to SBI in CKD patients and whether the prevalence of SBI differs in CKD stage or cause of CKD.

Methods. This is a cross-sectional study. A total of 375 subjects—335 with CKD and 40 with essential hypertension—were included. All subjects underwent magnetic resonance imaging (MRI) of the brain to detect SBI. Glomerular filtration rate (GFR) was estimated using Modification of Diet in Renal Disease equation, and cardiovascular risk factors were examined.

Results. The prevalence of SBI was 56.5% in all subjects. Among causes of CKD, hypertensive nephrosclerosis had a strong association with SBI. According to the estimated GFR (eGFR) stage, the more severe the stage of eGFR, the higher the prevalence of SBI (age-adjusted odds ratio [95% confidence interval] for eGFR 30–59, 15–29 and <15 versus ≥60 mL/min/1.73 m²: 1.34 [0.68–1.99], 1.94 [1.30–2.57] and 2.51 [1.91–3.10]). In multivariate logistic analysis, eGFR was related to SBI independently, in addition to age and blood pressure (P = 0.025). However, other traditional and non-traditional risk factors were not.

Conclusion. There was an independent association between eGFR and SBI. CKD patients should receive active detection of SBI and more intensive preventive management, especially for hypertension, should be needed in CKD patients to prevent SBI.

Prevalence and associations of coronary artery calcification in patients with stages 3 to 5 CKD without cardiovascular disease

BACKGROUND

Patients with chronic kidney disease (CKD) have a high prevalence of coronary artery calcification, suggesting that CKD itself is a risk factor for its occurrence. Existing studies are confounded by the inclusion of patients who may not have CKD by means of diagnostic criteria and by failing to account for existing cardiovascular disease.

STUDY DESIGN

Cross-sectional study.

PARTICIPANTS & SETTING

119 patients with CKD stages 3 to 5 (excluding dialysis) without known cardiovascular disease receiving care at a single center in Kingston, Ontario, Canada.

PREDICTORS

Glomerular filtration rate was estimated (eGFR) by using the 4-variable Modification of Diet in Renal Disease Study equation. Traditional and nontraditional coronary artery calcification risk factors were defined a priori.

OUTCOMES

Coronary artery calcification was measured by means of multislice computed tomographic scan.

RESULTS

Mean and median coronary artery calcification scores were 566.5 +/- 1,108 and 111 (interquartile range, 2 to 631.5), respectively. A total of 32.8% of patients showed little calcification (score, 0 to 10). Calcification correlated with age (r = 0.44; P < 0.001), body mass index (r = 0.28; P = 0.002), high-density lipoprotein cholesterol level (r = -0.23; P = 0.01), diabetes mellitus (r = 0.23; P = 0.01), and cardiovascular risk score (r = 0.35; P < 0.001). By means of multivariable linear regression controlling for eGFR and diabetes mellitus, age (beta = 0.05; 95% confidence interval, 0.03 to 0.06; P < 0.001), body mass index (beta = 0.04; 95% confidence interval, 0.02 to 0.07; P = 0.001), and serum calcium level (beta = 0.9; 95% confidence interval, 0.15 to 1.6; P = 0.02), were risk factors for coronary artery calcification.

LIMITATIONS

Inadequate sample size and uncontrolled confounding are possible limitations, but are unlikely to have changed the main study findings.

CONCLUSIONS

In this study, traditional cardiovascular disease risk factors and serum calcium level were associated with coronary artery calcification. No association was shown with eGFR. Studies exploring protective mechanisms against coronary artery calcification are needed.

Uric acid and incident kidney disease in the community

Uric acid may mediate aspects of the relationship between hypertension and kidney disease via renal vasoconstriction and systemic hypertension. To investigate the relationship between uric acid and subsequent reduced kidney function, limited-access data of 13,338 participants with intact kidney function in two community-based cohorts, the Atherosclerosis Risks in Communities and the Cardiovascular Health Study, were pooled. Mean baseline serum uric acid was 5.9 +/- 1.5 mg/dl, mean baseline serum creatinine was 0.9 +/- 0.2 mg/dl, and mean baseline estimated GFR was 90.4 +/- 19.4 ml/min/1.73 m(2). During 8.5 +/- 0.9 yr of follow-up, 712 (5.6%) had incident kidney disease defined by GFR decrease (>or=15 ml/min/1.73 m(2) with final GFR <60 ml/min/1.73 m(2)), while 302 (2.3%) individuals had incident kidney disease defined by creatinine increase (>or=0.4 mg/dl with final serum creatinine >1.4 mg/dl in men and 1.2 mg/dl in women). In GFR- and creatinine-based logistic regression models, baseline uric acid level was associated with increased risk for incident kidney disease (odds ratio 1.07 [95% confidence interval 1.01 to 1.14] and 1.11 [95% confidence interval 1.02 to 1.21] per 1-mg/dl increase in uric acid, respectively), after adjustment for age, gender, race, diabetes, systolic BP, hypertension, cardiovascular disease, left ventricular hypertrophy, smoking, alcohol use, education, lipids, albumin, hematocrit, baseline kidney function and cohort; therefore, elevated serum uric acid level is a modest, independent risk factor for incident kidney disease in the general population.

Waist-to-hip ratio, body mass index, and subsequent kidney disease and death

BACKGROUND

Chronic kidney disease (CKD) and obesity are important public health concerns. We examined the association between anthropomorphic measures and incident CKD and mortality.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Individual patient data pooled from the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study.

PREDICTORS

Waist-to-hip ratio (WHR), body mass index (BMI).

OUTCOMES & MEASUREMENTS

Incident CKD defined as serum creatinine level increase greater than 0.4 mg/dL with baseline creatinine level of 1.4 mg/dL or less in men and 1.2 mg/dL or less in women and final creatinine level greater than these levels, and, in separate analyses, estimated glomerular filtration rate (eGFR) decrease of 15 mL/min/1.73 m(2) or greater with baseline eGFR of 60 mL/min/1.73 m(2) or greater and final eGFR less than 60 mL/min/1.73 m(2). Multivariable logistic regression to determine the association between WHR, BMI, and outcomes. Cox models to evaluate a secondary composite outcome of all-cause mortality and incident CKD.

RESULTS

Of 13,324 individuals, mean WHR was 0.96 in men and 0.89 in women and mean BMI was 27.2 kg/m(2) in both men and women. During 9.3 years, 300 patients (2.3%) in creatinine-based models and 710 patients (5.5%) in eGFR-based models developed CKD. In creatinine-based models, each SD increase in WHR was associated with increased risk of incident CKD (odds ratio, 1.22; 95% confidence interval [CI], 1.05 to 1.43) and the composite outcome (hazard ratio, 1.12; 95% CI, 1.06 to 1.18), whereas each SD increase in BMI was not associated with CKD (odds ratio, 1.05; 95% CI, 0.93 to 1.20) and appeared protective for the composite outcome (hazard ratio, 0.94; 95% CI, 0.90 to 0.99). Results of eGFR-based models were similar.

LIMITATIONS

Single measures of creatinine, no albuminuria data.

CONCLUSIONS

WHR, but not BMI, is associated with incident CKD and mortality. Assessment of CKD risk should use WHR rather than BMI as an anthropomorphic measure of obesity.

Development of end stage renal disease following an acute cardiac event

We determined the rate and risk factors for end-stage renal disease (ESRD) in consecutive patients discharged after a cardiac event in a large, unbiased Canadian cohort that receives universal health coverage. A total of 8236 adults hospitalized over a 2 year period were followed for up to 7.5 years and the incidence of ESRD and mortality determined. Of these, 113 reached ESRD (stage 5). Patients with moderate (stage 3) and severe (stage 4) renal insufficiency were more likely to develop ESRD than those patients at stage 1 or 2. However, patients with moderate renal insufficiency were 78.6 times more likely to die than to develop ESRD. Absolute rates of progression to ESRD per 100-patient years were 0.08 at stages 1 and 2, 0.17 at stage 3 and 4.27 at stage 4. Age, diabetes, hypertension and congestive heart failure also predicted ESRD. We found that patients with stage 4 disease are at high risk of ESRD after a cardiac admission while those at stage 3 are far more likely to die than to develop ESRD.

Detection and awareness of moderate to advanced CKD by primary care practitioners: a cross-sectional study from Italy

BACKGROUND

Chronic kidney disease (CKD) is a strong independent predictor of cardiovascular disease. Although general practitioners (GPs) represent the first line for identification of these high-risk patients, their diagnostic approach to CKD is ill defined.

STUDY DESIGN

Cross-sectional evaluation of database of Italian GPs.

SETTING & PARTICIPANTS

Representative sample of adult Italian population regularly followed up by GPs in 2003.

OUTCOMES

Frequency of serum creatinine testing, prevalence of CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m(2)), awareness of CKD assessed from use of diagnostic codes (Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]) for CKD, and referral to nephrologists.

RESULTS

Of 451,548 individuals in the entire practice population, only 77,630 (17.2%) underwent serum creatinine testing. Female sex (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.06 to 1.12), advanced age (OR, 2.70; 95% CI, 2.63 to 2.78), diabetes (OR, 1.31; 95% CI, 1.20 to 1.42), hypertension (OR, 1.10; 95% CI, 1.02 to 1.19), autoimmune diseases (OR, 1.42; 95% CI, 1.11 to 1.82), and recurrent urinary tract infections (OR, 1.63; 95% CI, 1.10 to 2.42) were all associated with serum creatinine testing. Conversely, use of either nonsteroidal anti-inflammatory drugs (OR, 1.03; 95% CI, 0.89 to 1.21) or aminoglycosides or contrast media (OR, 0.78; 95% CI, 0.54 to 1.14) was not associated with serum creatinine testing. In the subgroup with serum creatinine data, the age-adjusted prevalence of CKD was 9.33% (11.93% in women, 6.49% in men). However, in patients with eGFR less than 60 mL/min/1.73 m(2), serum creatinine values were apparently normal (<1.2 mg/dL in women, <1.4 mg/dL in men) in 54%, and GPs used ICD-9-CM codes for CKD in only 15.2%. Referral to nephrologists ranged from 4.9% for patients with eGFR of 59 to 30 mL/min/1.73 m(2) to 55.7% for those with eGFR less than 30 mL/min/1.73 m(2).

LIMITATIONS

The prevalence of decreased kidney function may be overestimated because of the more frequent serum creatinine testing in sicker individuals and lack of creatinine calibration.

CONCLUSIONS

In primary care, CKD stages 3 to 5 are frequent, but its awareness is scarce because of limited rates of serum creatinine testing and difficulty recognizing decreased eGFR in the absence of increased serum creatinine testing.

Inflammation and cardiovascular events in individuals with and without chronic kidney disease

Inflammation and chronic kidney disease predict cardiovascular events. Here we evaluated markers of inflammation including fibrinogen, albumin and white blood cell count in individuals with and without stages 3-4 chronic kidney disease to assess inflammation as a risk factor for adverse events, the synergy between inflammation and chronic kidney disease, and the prognostic ability of these inflammatory markers relative to that of C-reactive protein. Using Atherosclerosis Risk in Communities and Cardiovascular Health Study data, inflammation was defined by worst quartile of at least 2 of these 3 markers. In Cox regression models, inflammation was assessed as a risk factor for a composite of cardiac events, stroke and mortality as well as components of this composite. Among 20 413 patients, inflammation was identified in 3594 and chronic kidney disease in 1649. In multivariable analyses, both inflammation and chronic kidney disease predicted all outcomes, but their interaction was non-significant. In 5597 patients with C-reactive protein levels, inflammation and elevated C-reactive protein had similar hazard ratios. When focusing only on individuals with the worst quartile of white cell count and albumin, results remained consistent.

Endotoxemia is related to systemic inflammation and atherosclerosis in peritoneal dialysis patients

BACKGROUND AND OBJECTIVES

Systemic inflammatory state is a hallmark of peritoneal dialysis (PD) patients, but its etiology remains obscure. Because circulating microbial products are an important cause of systemic immune activation in other conditions such as HIV infection, it was hypothesized that endotoxemia is a cause of systemic inflammatory state and atherosclerosis in PD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Plasma lipopolysaccharide (LPS) levels in 30 consecutive new PD patients were measured. The result was compared with serum C-reactive protein (CRP) level, peritoneal transport status, history of pre-existing cardiovascular diseases, and carotid intima media thickness (IMT) by Doppler ultrasound.

RESULTS

Among the 30 PD patients, there were 17 men. The average age was 53.7 +/- 15.1 yr. The average endotoxin concentration of PD patients was 0.44 +/- 0.18 EU/ml, which was significantly higher than that of patients with chronic kidney disease secondary to Ig-A nephropathy (IgAN) (0.035 +/- 0.009 EU/ml, P < 0.0001) and the controls (0.013 +/- 0.007 EU/ml, P < 0.0001). In PD patients, plasma LPS concentration had a significant correlation with serum CRP (r = 0.415, P = 0.025) and serum albumin level (r = -0.394, P = 0.034). In contrast, plasma LPS level did not correlate with Charlson's Comorbidity Index, peritoneal transport characteristics, or nutritional indices. Patients with pre-existing cardiovascular disease (CVD) had higher plasma LPS level than those without CVD (0.53 +/- 0.19 versus 0.36 +/- 0.16 EU/ml, P = 0.016). Plasma LPS level correlated with carotid IMT (r = 0.438, P = 0.016).

CONCLUSIONS

It was found that endotoxemia was probably common in PD patients, and the degree of circulating endotoxemia might be related to the severity of systemic inflammation and features of atherosclerosis. This result suggests that endotoxemia may have a contributory role to the systemic inflammatory state and accelerated atherosclerosis in PD patients.