Persistent elevation of C-reactive protein and ischemic heart disease in patients with continuous ambulatory peritoneal dialysis

Myocardial Perfusion Imaging and C-Reactive Protein in Myocardial Ischemia: A Retrospective Single-Center Study

BACKGROUND

Inflammation is an important mechanism in atherosclerosis and plaque formation. C-reactive protein (CRP) is a common inflammatory biomarker associated with the risk of coronary heart disease. We investigated the relationship of CRP with findings from myocardial perfusion imaging (MPI).

METHODS

In this retrospective study, 102 consecutive patients (mean age 71 years, 68% males) who underwent MPI (for diagnostic reasons or quantification of myocardial ischemia) and CRP determination (upper limit: 6 mg/L) within 1 month from MPI were included. The patients had no infection or recent acute coronary syndrome.

RESULTS

The median CRP level was 4 mg/L (2, 10) among the study population. Patients with raised CRP had higher summed stress score (SSS) (p = 0.006) and summed rest score (SRS) (p = 0.001) and higher risk for SSS > 3 (OR 9.25, 95% CI 2.03-42.13, p = 0.001) compared to those with low CRP. The association of SSS and SRS with CRP levels was more evident in patients over 70 years (p = 0.027 and p = 0.005, respectively). No significant difference in summed difference score was shown. The two groups had no difference in other risk factors (p > 0.05 for all comparisons).

CONCLUSION

a high level of CRP was associated with the presence and extent of stress-induced myocardial ischemia in MPI.

The Ratio of Extracellular Fluid to Total Body Water and Technique Survival in Peritoneal Dialysis Patients

Background

Patients receiving peritoneal dialysis experience a high technique failure rate and are often overhydrated. We examined whether an increased extracellular fluid volume (VECF) as a proportion of the total body water (VTBW) predicted technique survival (TS) in a prevalent patient cohort.

Methods

The VECFand VTBWwere estimated by multiple-frequency bioelectric impedance in 59 prevalent peritoneal dialysis patients (median time on dialysis 14 months). Demographic, biochemical (albumin, C-reactive protein, and ferritin), and anthropometric data, forearm muscle strength, nutritional score by three-point Subjective Global Assessment, residual renal function, dialysate-to-plasma (D/P) creatinine ratio, total weekly Kt/V urea, total creatinine clearance, normalized protein equivalent of nitrogen appearance, and midarm muscle circumference were also assessed. Technique survival was determined at 3 years, and significant predictors of TS were sought.

Results

In patient groups defined by falling above or below the median value for each parameter, only residual renal function ( p = 0.002), 24-hour ultrafiltrate volume ( p = 0.02), and VECF/ VTBWratio ( p = 0.05) were significant predictors of TS. Subjects with a higher than median VECF/ VTBWratio had a 3-year TS of 46%, compared to 78% in subjects with a lower than median value. In multivariate analysis, systolic blood pressure and VECF/ VTBWratio (both p < 0.05) were significant predictors of TS. C-reactive protein approached significance.

Conclusion

Increased ratio of extracellular fluid volume to total body water is associated with decreased TS in peritoneal dialysis.

The “Heart” of Peritoneal Dialysis: Residual Renal Function

The CANUSA study originally reported the importance of total small-solute clearance in predicting survival of peritoneal dialysis (PD) patients. However, subsequent reanalysis of data from the CANUSA study clearly demonstrated that the predictive power for mortality in PD patients was largely attributable to residual renal function (RRF) and not to the dose of PD. While this should not lead to the assumption that the dose of PD is unimportant, it does clearly indicate that the contribution of residual renal clearance and PD clearance to the overall survival of PD cannot be considered equivalent. In a previous study, we also demonstrated the importance of loss of RRF in predicting a heightened risk of mortality and cardiovascular death in PD patients. In this review, we focus our discussion on the different potential mechanisms that explain the important link between RRF and cardiovascular disease and survival of PD patients. We provide evidence to explain why RRF is so important to patients receiving long-term PD treatment and why it should be regarded as the “heart” of PD.

Association of serum angiopoietin-2 with malnutrition, inflammation, atherosclerosis and valvular calcification syndrome and outcome in peritoneal dialysis patients: a prospective cohort study

Background

To examine serum angiopoietin-2 (Angpt-2) in relation to malnutrition, inflammation, atherosclerosis and cardiac valvular calcification, so-called MIAC syndrome and its predictive role in outcomes of peritoneal dialysis (PD) patients.

Methods

A prospective observational study was conducted in 324 chronic PD patients. Biochemical analysis was performed at baseline for serum angiopoietins, albumin and high sensitive C-reactive protein (hs-CRP) and echocardiography was done to detect cardiac valvular calcification. Primary study end points were fatal or nonfatal cardiovascular events and mortality.

Results

The median of serum Angpt-2 levels was 5.44 ng/mL (interquartile range, 3.41–7.85). Across the three tertiles of serum Angpt-2, a significant trend effect was observed for body mass index, normalized protein catabolic rate, calcium × phosphorus product, hs-CRP, brain natriuretic peptide, lower-density lipoprotein cholesterol, left ventricular ejection fraction, total weekly urea clearance and residual renal function (all p < 0.05). Serum Angpt-2 showed a significant increase across the four groups of patients with increasing components of MIAC syndrome (p < 0.001). There were 77 deaths and 57 cardiovascular events. High serum Angpt-2 was an independent predictor of fatal and nonfatal cardiovascular events in PD patients (p = 0.02), however serum Angpt-2 was not an independent predictor of all-cause mortality (p = 0.3).

Conclusions

Serum Angpt-2 showed close association with valvular calcification, atherosclerosis, inflammation and malnutrition, having significant independent prognostic value and is useful for cardiovascular event stratification in chronic PD patients. Angpt-2 might be a potential mediator of increased cardiovascular risk in patients undergoing PD treatment.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1687-0) contains supplementary material, which is available to authorized users.

Does Residual Renal Function Have a Beneficial Effect on Patient and Technique Survival in Peritoneal Dialysis Patients?

Objectives:

Residual renal function (RRF) at the initiation of peritoneal dialysis (PD) therapy can be a predictor of survival in stable PD patients. The aim of the present study was to investigate PD patients regarding the effect of baseline RRF on patient and technique survival.

Methods:

Urine output at the beginning of PD therapy was evaluated retrospectively in 202 PD patients. Patients were divided into two groups: patients with anuria (urine output ≤100 ml/day) and patients without anuria (urine output >100 ml/day).

Results:

The number of patients with anuria was 58 in which 38 patients were females. The mean age of the patients was 42.8±14.9 years. The mean follow-up period was 44.2±35 months. Twelve percent of patients with anuria had history of hemodialysis (HD).

One hundred forty-four had no anuria (68 females, mean age 43.7±14.5 years, mean follow-up period 39.6±26.1 months, mean urine volume 592±442 ml). Twenty-three patients had received HD therapy before. Sixty-five had anuria in the following 22.5±19.6 months.

At the beginning of therapy, systolic and diastolic blood pressures were lower in patients with oliguria than in patients without oliguria (p<0.001), but C-reactive protein (p=0.004) and ferritin (p<0.001) levels were higher. There was no difference between two groups regarding the other parameters (age, follow-up periods, presence of diabetes, ultrafiltration volumes, albumin, hemoglobin, calcium phosphorus product, parathormone, and Kt/V levels) (p>0.05).

The peritonitis rate was one episode per 28.2 versus 30 patient-months for the anuric and non-anuric groups, respectively (p>0.05).

For Kaplan–Meier survival analysis, the mean technique survival rates at 1 and 3 years were 97% and 86.6% in patients without anuria and 94% and 85.3% in patients with anuria, respectively. The 5-year technique survival rates according to residual volume states were not statistically significant with log-rank test (p>0.05).

The 1-, 3-, and 5-year survival rates were 96.9%, 89.6%, and 86.5% in patients without anuria, respectively, whereas they were 87.3%, 77.3%, and 53.7% in patients with anuria, respectively. The 5-year survival rates according to residual volume states were statistically significant (p<0.05).

Conclusion:

RRF at the beginning of PD has an important and positive impact on patient survival in PD patients. Peritonitis rates and technique survival were not different for patients with anuria and without anuria.

Increasing high-sensitive C-reactive protein level predicts peritonitis risk in chronic peritoneal dialysis patients

Background

The aim of this study was to evaluate whether a high baseline level of high-sensitivity C-reactive protein (hs-CRP) or changes in the level predicts the risk of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD).

Methods

A prospective, cross-sectional, case–control study was conducted in a single hospital-based PD unit. A total of 327 patients were included in the study. Serum hs-CRP was measured annually for 2 years. Patients were divided into 4 groups according to the changes in annual hs-CRP levels (at baseline and at 1 year intervals): group 1 (from <5 mg/L to <5 mg/L, n = 171), group 2 (from <5 mg/L to ≥5 mg/L, n = 45), group 3 (from ≥5 mg/L to <5 mg/L, n = 45), and group 4 (from ≥5 mg/L to ≥5 mg/L, n = 80). Demographics, biochemistry results, PD adequacy indices, and peritonitis risk were compared between the groups.

Results

The initial serum albumin level was similar in the 4 groups (p = 0.12). There was a negative linear correlation between the serial albumin change (∆alb) and serial hs-CRP change (∆hs-CRP; r = −0.154, p = 0.005). The hazard ratio (HR) for peritonitis was significantly higher in group 2 (HR = 1, reference) than in group 4 (HR = 0.401, 95% CI 0.209 − 0.769). Group 2 had a greater serum albumin decline rate (∆alb: –3% ± 9%) and hs-CRP elevation rate (∆hs-CRP: 835% ± 1232%) compared to those for the other groups.

Conclusions

A progressive increase in the hs-CRP level was associated with a corresponding decline in the serum albumin level. Progressive rather than persistently high levels of serum hs-CRP predicted peritonitis risk in CAPD patients.

Survival advantage of normal weight in peritoneal dialysis patients

INTRODUCTION

A high body mass index (BMI) is a positive predictor of outcome in hemodialysis. But reports for peritoneal dialysis (PD) have been less numerous. The aim of the present investigation was to study the association between BMI and survival among PD patients and to discuss the main risk factors affecting survival.

MATERIALS AND METHODS

A total of 159 patients who received PD from 1 January 2006 to 31 December 2010 at the Department of Nephrology in the Third Affiliated Hospital of Soochow University were enrolled in the study. Blood samples and baseline characteristics of the study cohort were obtained at the start of PD. Patient survival status was recorded through 31 December 2010.

RESULTS

Patients were stratified into two groups as normal weight (BMI, 18.5-24.9) and overweight (BMI, 25.0-29.9). Kaplan-Meier survival curve revealed that the normal weight patients had survival advantage over overweight patients (p < 0.01, by log-rank test). Cox proportional hazard models revealed that BMI, age, diabetes mellitus, coronary vascular disease, congestive heart failure and lipoprotein(a) (Lp(a)) were significant risk factors associated with all-cause mortality (p < 0.05). After adjustment for these covariates, survival was consistently higher for normal weight patients (p < 0.01). Furthermore, the study demonstrated that normal weight patients had lower serum Lp(a) (p < 0.05), C-reactive protein (CRP) (p < 0.05), and peritonitis rate (p < 0.05) compared with overweight patients.

CONCLUSION

The results indicated that normal BMI at the commencement of PD had significant survival advantage in our study. The mechanisms for this might be related to lower cardiovascular risk, less chronic inflammation, and peritonitis prevalence.

Cardiovascular risk in diabetic end-stage renal disease patients

Diabetes mellitus is the leading cause of end-stage renal disease (ESRD), accounting for 54% of all incident cases according to the US Renal Data System. These patients suffer an extremely high mortality rate due to the very high incidence of cardiovascular disease. A significant proportion of these patients already has established cardiovascular disease at the time of initiation of dialysis treatment. More importantly, as these patients develop progressive kidney dysfunction, they are not only subjected to traditional Framingham risk factors, but, more importantly, to a whole host of "kidney disease-related risk factors" that further accelerate the progression of cardiovascular disease and thus contribute to adverse cardiovascular outcomes. The present article provides an updated view on the multitude of traditional Framingham risk factors and kidney disease-related risk factors that diabetic ESRD patients are subjected to. A better understanding of the different cardiovascular risk factors will be fundamental to institute early detection programs, as well as to provide aggressive cardiovascular management of these patients.

C-Reactive Protein in End-Stage Renal Disease: Are There Reasons to Measure It?

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality in end-stage renal disease (ESRD) patients. As traditional risk factors cannot alone explain the unacceptable high prevalence and incidence of CVD in this population, inflammation (a common phenomenon in ESRD), and other non-traditional risk factors are likely to contribute. Among several inflammatory biomarkers used to assess inflammation, high-sensitivity C-reactive protein (hs-CRP) has attracted the most interest. Indeed, in the general population the consistency of prognostic data for hs-CRP and the practicality of its use have led to suggestions that CRP should be used as a clinical criterion for global cardiovascular risk prediction. As CRP is so strongly associated with vascular disease, it has been suggested that this protein is not only a marker, but also a mediator, of atherogenesis. Indeed, recent in vitro data from studies on endothelial cells, monocytes-macrophages and smooth muscle cells support a direct role for CRP in atherogenesis. In ESRD, hs-CRP has been proven to be a strong predictor of both cardiovascular and all-cause mortality, and associated with oxidative stress, vascular calcification and endothelial dysfunction. As recent studies suggest that interleukin-6 may be a somewhat better outcome predictor than hs-CRP, comparative studies are needed to evaluate which inflammation biomarker is the most cost-effective predictor of outcome in the ESRD patient population.

Impact of C-reactive protein and pulse pressure evaluated at the start of peritoneal dialysis on cardiovascular events in the course of treatment with peritoneal dialysis

BACKGROUND

Despite a reduced number of infectious complications, cardiovascular (CV) mortality remains unchanged in peritoneal dialysis (PD) patients. The aim of this study was to evaluate the effects of high-sensitivity C-reactive protein (hs-CRP) and pulse pressure (PP) at the start of PD on the development of CV events (CVEs) in these patients.

METHODS

The study population was comprised of 291 patients that started PD between January 2003 and June 2008 and were treated for more than 6 months. Baseline clinical, biochemical, and echocardiographic data, indices of dialysis adequacy, and peritoneal transport rate were reviewed retrospectively. The clinical outcome was the occurrence of a CVE.

RESULTS

Mean duration of follow-up was 28 (range 6 - 70) months. A CVE was observed in 33 patients (11.3%). The 1-, 3-, and 5-year cumulative incidences of CVEs were 4.0%, 13.7%, and 27.5%, respectively. Although multiple variables were correlated with the prevalence of a CVE in the univariate analysis, hs-CRP, PP, and comorbidity remained significant after adjustment: hs-CRP: odds ratio (OR) 4.09 (1.53 - 10.95), p = 0.005; PP: OR 2.79 (1.26 - 6.17), p = 0.012. PP and hs-CRP, which were not intercorrelated in our data, combined adversely to increase the incidence of CVEs. The incidence of CVEs increased with the number of risk factors, which included high hs-CRP, high PP, and the presence of comorbidity (no risk factor, 0%; 1 risk factor, 1.5%; 2 risk factors, 30.8%; 3 risk factors, 53.9%).

CONCLUSIONS

Our study suggests that measurements of hs-CRP and PP at the start of PD may be helpful in predicting the development of CVEs in the course of treatment with PD.

Is valvular calcification a part of the missing link between residual kidney function and cardiac hypertrophy in peritoneal dialysis patients?

BACKGROUND AND OBJECTIVES

Residual renal function (RRF) predicts survival and shows an important inverse relation with cardiac hypertrophy in peritoneal dialysis (PD) patients. We hypothesized that valvular calcification and the calcification milieu may be part of the process linking loss of RRF and cardiac hypertrophy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cross-sectional study was conducted by performing two-dimensional echocardiography on 230 PD patients to assess valvular calcification and left ventricular (LV) mass and collecting 24-h urine for estimation of RRF.

RESULTS

Patients having valvular calcification had lower RRF than those without. Patients with no RRF showed higher calcium-phosphorus product (Ca x P) and C-reactive protein (CRP). Using multiple logistic regression analysis, every 1-ml/min per 1.73 m(2) increase in residual GFR was associated with a 28% reduction in the risk for valvular calcification. The association was lost after additional adjustment for Ca x P and CRP. Using multiple linear regression analysis, loss of RRF showed significant association with increased LV mass index, but this association was lost after additional adjustment for CRP, Ca x P, and valvular calcification. Patients with all three calcification risk factors, namely inflammation, high CaxP, and no RRF, showed the highest prevalence of valvular calcification and had the most severe cardiac hypertrophy.

CONCLUSIONS

The association among loss of RRF, valvular calcification, and cardiac hypertrophy was closely linked to increased inflammation and high Ca x P in PD patients. These data suggest that valvular calcification and the calcification milieu are part of the processes linking loss of RRF and worsening cardiac hypertrophy in PD.

[Correlation between dialysis solution type and cardiovascular morbidity rate in patients undergoing continuous ambulatory peritoneal dialysis]

BACKGROUND/AIM

Peritoneal dialysis (PD) patients have an increased risk for cardiovascular diseases. The aim of the study was to evaluate the cardiovascular changes in patients undergoing chronic PD and the eventual existing differences depending on biocompatibility of dialysis solutions.

METHODS

After 3 +/- 2 years of starting PD, 21 PD patients on the treatment with bioincompatible dialysis solutions (conventional glucose- based solutions: PDP-1), average age 47.43 +/- 12.87 years, and 21 PD patients on the treatment with biocompatible dialysis solutions (neutral solutions with lower level of glucose degradation products, lower concentration of Ca2+ and neutral pH: PDP-2), average age 68.62 +/- 13.98 years, participated in the longitudinal study. The average number of episodes of peritonitis was similar in both groups: 1 episode per 36 months of the treatment. The control group included 21 patients with preterminal phase of chronic renal failure (Glomerular Filtration Rate: 22.19 +/- 10.73 ml/min), average age 65.29 +/- 13.74 years. All the patients underwent transthoracal echocardiography (in order to detect: eject fraction (EF), left ventricular hypertrophy (LVH), and valvular calcification (VC) and B-mode ultrasonography of common carotid artery (CCA): IMT, lumen narrowing, and plaque detection.

RESULTS

The values of EF were: in PDP-1 group 62.05 +/- 5.65%, in PDP-2 group 53.43 +/- 7.47%, and in the control group 56.71 +/- 8.12% (Bonferroni test, p = 0.001). The recorded LVH was: in PDP-1 group in 47.6% of the patients; in PDP-2 group in 61.9% of the patients; and in control the group in 52.4% (chi2 test; p = 0.639). The detected VC was: in PDP-1 in 52.4% of the patients, in PDP-2 group in 42.9% of the patients, and in the control group in 23.8% of the patients (chi2 test; p = 0.776). The IMT was: in PDP-1 group 1.26 +/- 0.54 mm, in PDP-2 group 1.23 +/- 0.32, and in the control group 1.25 +/- 0.27 mm (Bonferroni test; p = 0.981). An average lumen narrowing was: in PDP-1 group 13.78 +/- 18.26%, in PDP-2 group 18.57 +/- 22.98%, and in the control group 25.00 +/- 28.02% (Kruskal Wallis test; p = 0.413). Calcified plaques of CCA were detected in PDP-1 group in 61.9% of the patients, in PDP-2 group in 85.7%, of the patients and p = 0.159).

CONCLUSION

Generally, PD had a significant influence on cardiovascular morbidity in the treated patients, especially on the left ventricular function and peripheral atherosclerosis. The age of the patients had more influence on acceleration of atherosclerosis than the length of dialysis or biocompatibility of dialysis solutions.

Serum high-sensitivity C-reactive protein is not increased in patients with IgA nephropathy

BACKGROUND/AIMS

The development of renal injury in glomerulonephritis (GN) has been related to systemic inflammatory mediators. We investigated whether serum high-sensitivity C-reactive protein (hs-CRP) is a marker reflecting the inflammatory pathogenesis of primary GN.

METHODS

We compared serum hs-CRP levels in 192 patients with IgA nephropathy (IgAN), 43 patients with membranous nephropathy (MN), and 25 patients with minimal change disease (MCD) undergoing kidney biopsy and 638 matched controls.

RESULTS

There were no differences in hs-CRP levels between controls (median 0.08 mg/dl; range 0.03-1.87 mg/dl) and patients with IgAN (0.08 mg/dl; 0.03-3.13 mg/dl), MN (0.07 mg/dl; 0.03-0.99 mg/dl) or MCD (0.08 mg/dl; 0.03-1.75 mg/dl). In patients with IgAN, hs-CRP levels did not differ according to Haas' pathological subclasses or subsequent renal outcomes. In the IgAN group, hs-CRP showed positive correlations with IgA, uric acid, systolic blood pressure, BMI and age. Hs-CRP level was significantly higher in male than in female IgAN patients. Serum IgA concentration was the strongest independent correlate with hs-CRP levels, and gender and BMI were also independently associated with hs-CRP. There were no correlations between hs-CRP and markers of disease activity.

CONCLUSION

It is likely that hs-CRP does not closely reflect inflammatory pathogenesis in patients with IgAN, MN and MCD.

Higher serum C-reactive protein predicts short and long-term outcomes in peritoneal dialysis-associated peritonitis

We examined the association between C-reactive protein (CRP) and short- and long-term adverse outcomes in peritoneal dialysis (PD)-associated peritonitis. Serum CRP levels were measured at baseline and 3 weeks after initiation of treatment in 209 patients with an incident episode of peritonitis between 1 January 1999 and 31 March 2005. Patients were followed until 31 May 2005. Short-term adverse outcomes included switch to hemodialysis, death, persistent infection beyond planned therapy duration, and relapse; long-term adverse outcomes included a subsequent peritonitis event or death. After adjustment for age, gender, diabetes, duration of renal replacement therapy and causative organism, patients with higher CRP levels at diagnosis had a greater odds of an adverse short-term outcome (odds ratio 1.57 (95% confidence interval (CI): 0.61-4.02), 2.73 (95% CI: 1.09-6.87), and 3.38 (95% CI: 1.36-8.42) in the second, third, and highest quartiles). In patients who met criteria for resolution of peritonitis 3 weeks after diagnosis, those with higher CRP levels had a greater risk of a long-term adverse outcome (hazard ratio 1.79 (95% CI: 1.05-3.07)). In conclusion, higher levels of CRP are independently associated with adverse outcomes in PD-associated peritonitis. Serial measurement of this marker during the course of peritonitis may facilitate earlier identification of individuals at greater risk of complications.

Do inflammatory markers add predictive information of death beyond that provided by age and comorbidity in chronic renal failure patients?

BACKGROUND

Elevated levels of inflammatory markers have been shown to be associated with increased mortality in chronic kidney disease (CKD) patients. Comorbid indexes are also helpful clinical instruments for predicting mortality. At present, it is unknown whether inflammatory markers add predictive information of death beyond that provided by comorbid indexes.

METHODS

This observational single-centre study included 404 patients (mean age 63+/-16 years) with CKD stage 4 and 5 predialysis who were prospectively followed-up. Data obtained at baseline: demographics, grade of comorbidity by Davies index, serum albumin, creatinine clearance, total white blood cell (WBC), polymorphonuclear leukocyte (PMN) counts, and high-sensitivity C-reactive protein (CRP) were analysed as potential determinants of the subsequent all-cause mortality. Receiver-operating characteristic (ROC) curves were used to determine the values of CRP, WBC and PMN most closely related to mortality. These cut-off values were used to define subgroups with high or low inflammatory markers. Uni- and multivariate Cox regression models were performed.

RESULTS

Median follow-up time was 583 days, with a mortality of 26%, and overall survival rate of 47%. In unadjusted Cox models, inflammatory markers (CRP, WBC and PMN) were all significantly associated with all-cause mortality. Age (HR 1.05; 95% CI 1.03-1.07, P<0.0001) and comorbid index (HR 2.15; 95% CI 1.54-3.00, P<0.0001) were strongly associated with mortality. The introduction of inflammatory markers into the multivariate Cox regression model did not add significant predictive power. In a stepwise Cox model, the age, comorbid index, serum albumin levels and creatinine clearance were the best predictive variables of mortality.

CONCLUSIONS

Although elevated inflammatory markers are associated with a worse outcome in CKD patients, they did not add predictive information of all-cause mortality beyond that provided by age and the comorbid index.

The effect of single and repeatedly high concentrations of C-reactive protein on cardiovascular and non-cardiovascular mortality in patients starting with dialysis

BACKGROUND

Single measurements of C-reactive protein (CRP) predict cardiovascular mortality in dialysis patients. However, CRP can be temporarily elevated due to infections. Therefore, we investigated the effect of single and repeatedly high concentrations of CRP on cardiovascular and non-cardiovascular mortality in incident dialysis patients.

METHODS

In the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD), patients starting with dialysis were enrolled between 1997 and 2002. From 635 patients, plasma CRP concentrations were determined at 3 and 6 months of follow-up. Concentrations >10 mg/l were regarded as 'high'. Patients were followed until time of death, or censored at the end of follow-up (1 May 2004). Cox regression models were performed to compare mortality between patients with repeatedly low CRP, with varying CRP and with repeatedly high CRP.

RESULTS

At the end of follow-up, 247 patients had died, of which 107 patients died of cardiovascular disease (47.8%). Patients with low CRP(3 months) and high CRP(6 months) were at increased cardiovascular [adjusted hazard ratio (HR): 2.59, 95% CI: 1.25-5.37] and non-cardiovascular (adjusted HR: 2.18, 95% CI: 1.11-4.28) mortality risk compared with patients with low CRP on both occasions. Moreover, patients with high CRP on both occasions had a higher cardiovascular (adjusted HR: 1.51, 95% CI: 0.72-3.18) and non-cardiovascular (adjusted HR: 2.25, 95% CI: 0.96-5.28) mortality risk than patients with high CRP(3 months) and low CRP(6 months).

CONCLUSIONS

Single and repeatedly high concentrations of CRP (>10 mg/l) are related to both cardiovascular and non-cardiovascular mortality in dialysis patients. A high CRP concentration, therefore, has implications for the treatment of cardiovascular as well as non-cardiovascular disease.

Why Do Dialysis Patients Develop a Heart of Stone and Bone of China?

Vascular calcification is a common complication of end-stage renal disease (ESRD). The mechanisms responsible are complex and have so far been considered to be mainly the result of a passive mechanism due to elevated PO(4) levels and high Ca x PO(4) ion product resulting in saturated plasma. However, recent results suggest that also other features, commonly observed in the uremic milieu, such as chronic inflammation, hyperleptinemia and a dysregulation of various mineral-regulating proteins might also contribute to an enhanced calcification process. Moreover, as an inverse relationship between vascular calcification and bone density has been documented in ESRD, it could be speculated that pathologically low bone remodelling (adynamic bone disease) associated with active vitamin D treatment and low parathyroid hormone (PTH) levels may predispose to ectopic calcification of vessels, valves and heart. As patients with vascular calcification have a higher intake of calcium-containing PO(4) binders, novel, non-calcium containing PO(4) binders may diminish the risk of progressive vascular calcification in this patient group. Further studies are needed to elucidate the respective role of chronic inflammation, hyperleptinemia and PTH-lowering therapies in this fatal complication of ESRD.

Effect of dialysis modality on plasma fibrinogen concentration: A meta-analysis

BACKGROUND

Concentrations of plasma fibrinogen, a vascular risk factor, tend to be greater in patients on peritoneal dialysis (PD) than hemodialysis (HD) therapy, like concentrations of serum cholesterol, lipoprotein(a), and transthyretin, despite the substantial loss of protein during PD. Worse vascular outcome has been noted in PD patients compared with HD patients in several studies.

METHODS

In this study, the mean difference in plasma fibrinogen levels (PD-HD) was quantified by means of meta-analysis of mean differences found in 12 cohorts with both PD and HD patients (set 1; N = 630) by using a fixed-effects model and meta-analysis of mean fibrinogen values reported in 30 cohorts of patients on a single dialysis modality (set 2; 8 PD cohorts, 22 HD cohorts; N = 2,096) by using a mixed model.

RESULTS

On meta-analysis, the weighted mean difference (PD-HD) was 105 mg/dL (95% confidence interval [CI], 86 to 124 [3.1 micromol/L; 95% CI, 2.5 to 3.6]) in set 1 and 103 mg/dL (95% CI, 53 to 153 [3.0 micromol/L; 95% CI, 1.6 to 4.5) in set 2.

CONCLUSION

Like other vascular risk factors, such as cholesterol and lipoprotein(a), plasma fibrinogen level is markedly greater in PD than HD patients, with an approximate difference of 100 mg/dL [2.9 mumol/L]. Different plasma reference ranges for fibrinogen need to be defined for PD and HD patients. The mechanism for the difference and the possible role of hyperfibrinogenemia in worsening vascular disease in PD patients deserve study.

Prevalence of coronary artery disease using thallium-201 single photon emission computed tomography among patients newly undergoing chronic peritoneal dialysis and its association with mortality

BACKGROUND

Previous data about the prevalence of coronary artery disease in dialysis patients were mainly based on history or electrocardiogram.

METHODS

We evaluated the prevalence of coronary artery disease using routine thallium-201 single photon emission computed tomography (SPECT) in 227 patients at the start of chronic peritoneal dialysis between January 1996 and October 2003. We also analyzed its association with mortality.

RESULTS

Fifty-one patients (22.5%) were positive on thallium SPECT. There were significant differences in age, underlying diabetic nephropathy, and C-reactive protein (CRP), serum albumin, total cholesterol, and prealbumin levels among patients positive and negative on thallium SPECT. Multivariate logistic regression analysis showed that age (> or =60 years), underlying diabetic nephropathy, and CRP (> or =0.5 mg/dl) were independent predictors of positive thallium SPECT, with the patients positive for all three factors having a probability for positive thallium SPECT of 43%, whereas patients negative for all three factors had a probability of only 4%. Ninety patients died, and 137 survived during the median follow-up period of 34 (range 3-99) months. Kaplan-Meier survival analysis revealed that age, underlying diabetic nephropathy, serum albumin, prealbumin, and CRP levels, positive thallium SPECT, and smoking affected survival. Survival was not different according to gender, presence of hypertension, body mass index, total cholesterol, or lipoprotein(a). Cox regression analysis showed that only underlying diabetic nephropathy and age (> or =60 years) were independent predictors of mortality.

CONCLUSIONS

We found that 22.5% of the patients who started chronic peritoneal dialysis had a positive thallium SPECT. Age, underlying diabetic nephropathy, and CRP were independent predictors of a positive thallium SPECT. Underlying diabetic nephropathy and age, but not positive thallium SPECT, were independent predictors of mortality.

Continuous peritoneal dialysis-associated peritonitis: a review and current concepts

The percentage of end-stage renal disease (ESRD) patients in the United States maintained on continuous peritoneal dialysis (CPD) therapy is decreasing. Complications from CPD therapy, including peritonitis, may be the reason for the decline. Improvements in CPD technology and a better understanding of the risk factors that predispose patients to the development of peritonitis have been responsible for a decline in the rate of peritonitis. Yet peritonitis remains a significant cause of patient morbidity and mortality and the overall outcome of peritonitis is not acceptable. Factors that have limited our ability to lessen the impact of peritonitis include a lack of data on dosing antibiotics in patients on continuous cycling peritoneal dialysis (CCPD) therapy, a lack of knowledge concerning the biology of bacterial biofilm, and the development of resistance to the current prophylactic antibiotic protocols. Further studies are needed concerning the optimal management of the peritoneal catheter and whether it is feasible to resume CPD therapy after catheter removal.

Malnutrition and inflammation in peritoneal dialysis patients

BACKGROUND

Malnutrition, cardiovascular disease, and heightened inflammation are highly prevalent in dialysis patients, and major contributors to morbidity and mortality. We have investigated the inter-relationship between malnutrition and inflammation, and their impact on morbidity and mortality in peritoneal dialysis (PD) patients.

METHOD

We enrolled 63 PD patients beginning in November 2000, and measured C-reactive protein (CRP) and various nutritional markers, including prealbumin.

RESULTS

CRP level was elevated in 29% of the PD patients. Diabetics had higher CRP than non-diabetics (24 vs. 9.3 mg/L, P = 0.016). Patients who were hospitalized during the study had higher enrollment CRP (16 vs. 12.5 mg/L, P = 0.05) and lower enrollment albumin (3.5 vs. 3.9 g/dL, P = 0.002), blood urea nitrogen (BUN) (40 vs. 49 mg/dL, P = 0.034), and protein catabolic rate (nPCR) (0.88 vs. 1.0 g/kg/day, P = 0.02) than those who were not hospitalized. Enrollment level of CRP was inversely correlated with nutritional markers prealbumin (r = -0.5, P < 0.0001) and creatinine (r =-0.35, P < 0.01). After adjusting for age, race, gender, diabetes, and CRP level, prealbumin continued to correlate with other nutritional markers. There was a trend toward association of elevated CRP with all-cause mortality in PD patients.

CONCLUSION

It is useful to incorporate prealbumin and CRP in the regular assessment of PD patients, whose survival may be improved by better management of malnutrition and inflammation.

C-reactive protein as a cardiovascular risk factor and its therapeutic implications in end-stage renal disease patients

We observed the association between a persistent elevation of C-reactive protein (CRP) level and the presence of ischemic heart disease in 73 peritoneal dialysis (PD) patients. Twenty-six patients showed an elevation of CRP for more than 6 months. Seventeen (65%) of the 26 patients had positive thallium single photon computed tomography (SPECT). Three of 9 patients who had a persistent elevation of CRP and negative thallium SPECT had a history of cerebral infarction or peripheral vascular disease. Therefore, 77% (20/26) of an elevated CRP level that lasted longer than 6 months can be explained by the presence of atherosclerotic vascular disease. There are as yet no valid recommendations on how chronic inflammation should be handled. We found that aspirin 200 mg daily for 8 weeks induce no significant changes of the CRP levels in PD patients (0.22 vs. 0.18 mg/dL, p > 0.05). However, 62 HD patients were randomly assigned to treatment group (simvastatin 20 mg/day) and control group. After 8 weeks medication, hs-CRP levels significantly reduced from a median of 0.23 mg/dL to 0.12 mg/dL.

Is a single time point C-reactive protein predictive of outcome in peritoneal dialysis patients?

C-reactive protein is the prototype marker of inflammation and has been shown to predict mortality in hemodialysis patients. However, it remains uncertain as to whether a single C-reactive protein level has similar prognostic significance in peritoneal dialysis patients. A single high-sensitivity C-reactive protein (hs-CRP) level was measured in 246 continuous ambulatory peritoneal dialysis patients without active infections at study baseline together with indices of dialysis adequacy, echocardiographic parameters (left ventricular mass index, left ventricular dimensions, and ejection fraction), nutrition markers (serum albumin, dietary intake, and subjective global assessment) and biochemical parameters (hemoglobin, lipids, calcium, and phosphate). The cohort was then followed-up prospectively for a median of 24 mo (range, 2 to 34 mo), and outcomes were studied in relation to these parameters. Fifty-nine patients died (36 from cardiovascular causes) during the follow-up period. The median hs-CRP level was 2.84 mg/L (range, 0.20 to 94.24 mg/L). Patients were stratified into tertiles according to baseline hs-CRP, namely those with hs-CRP < or = 1.26 mg/L, 1.27 to 5.54 mg/L, and > or = 5.55 mg/L. Those with higher hs-CRP were significantly older (P < 0.001), had greater body mass index (P < 0.001), higher prevalence of coronary artery disease (P = 0.003), and greater left ventricular mass index (P < 0.001). One-year overall mortality was 3.9% (lower) versus 8.8% (middle) versus 21.3% (upper tertile) (P < 0.0001). Cardiovascular death rate was 2.7% (lower) versus 5.2% (middle) versus 16.2% (upper tertile) (P < 0.0001). Multivariable Cox regression analysis showed that every 1 mg/L increase in hs-CRP was independently predictive of higher all-cause mortality (hazard ratio [HR], 1.02; 95% CI, 1.01 to 1.04; P = 0.002) and cardiovascular mortality (HR, 1.03; 95% CI, 1.01 to 1.05; P = 0.001) in peritoneal dialysis patients. Other significant predictors for all-cause mortality included age (HR, 1.07; 95% CI, 1.04 to 1.10), gender (HR, 0.49; 95% CI, 0.27 to 0.90), atherosclerotic vascular disease (HR, 2.65; 95% CI, 1.46 to 4.80), left ventricular mass index (HR, 1.01; 95% CI, 1.00 to 1.01) and residual GFR (HR, 0.53; 95% CI, 0.38 to 0.75). Age (HR, 1.06; 95% CI, 1.02 to 1.10), history of heart failure (HR, 3.31; 95% CI, 1.36 to 8.08), atherosclerotic vascular disease (HR, 3.20; 95% CI, 1.43 to 7.13), and residual GFR (HR, 0.57; 95% CI, 0.38 to 0.86) were also independently predictive of cardiovascular mortality. In conclusion, a single, random hs-CRP level has significant and independent prognostic value in PD patients.

An association between coronary artery calcification score, lipid profile, and selected markers of chronic inflammation in ESRD patients treated with peritoneal dialysis

BACKGROUND

Chronic uremia is considered a proinflammatory state associated with high cardiovascular morbidity and mortality. The aim of the present study is to evaluate the potential relationship between the prevalence of coronary artery calcification (CAC) and selected factors that may be involved in the process of atherogenesis (lipid profile, acute-phase reactants, growth factors, and cytokines).

METHODS

The study group consisted of 43 patients (19 women, 24 men) with a mean age of 50.6 +/- 13.4 years treated with peritoneal dialysis (PD) for a median period of 15 months (range, 2 to 96 months). Only patients with sinus rhythm were included. CAC score (CaSc) was measured using multirow spiral computed tomography (MSCT). As parameters of lipid profile, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were assayed. C-reactive protein (CRP) and fibrinogen represented the level of acute-phase activation. Proinflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor-alpha [TNF-alpha]), leptin, and basic fibroblast growth factor (bFGF) also were measured.

RESULTS

Median CaSc equaled 17.9 Agatston units (range, 0 to 5,502 Agatston units). No calcification was detected in 20 subjects (46.5%; CaSc < 10 Agatston units). CaSc correlated with age (R = 0.57; P < 0.0001), body mass index (R = 0.42; P < 0.005), and serum leptin (R = 0.3; P < 0.05) and CRP levels (R = 0.38; P < 0.05). The correlation with PD therapy duration was borderline statistically significant (P = 0.063). Patients with the greatest values for CaSc (> 400 Agatston units) were characterized by significantly greater levels of IL-6, bFGF, and CRP compared with subjects with a CaSc less than 10 Agatston units (P < 0.05 for all). Patients with history of coronary artery disease (CAD) had significantly greater CaSc values (median, 778.6 versus 3.3 Agatston units; P < 0.001) compared with those without CAD. Serum triglyceride levels were significantly greater and HDL cholesterol levels were significantly lower in patients with CAD. The first group also was characterized by significantly greater serum TNF-alpha (P < 0.01) and CRP levels (P < 0.005). In multiple regression analysis, only age was independently associated with CaSc (beta = 0.45; P = 0.002).

CONCLUSION

Our results may suggest an association between CAC and chronic inflammation activity in the mentioned group of patients. To our knowledge, this is the first study reporting the prevalence of CAC in PD patients using the MSCT method. The association between CaSc results and classic, as well as inflammatory, risk factors for CAD found in this study should be interpreted with caution because of its method limitations (cross-sectional design, heterogeneity of study population, and small number of studied patients).

Comorbidity and cardiovascular risk factors in patients with chronic kidney disease

The mortality rate among dialysis patients is high. Although guidelines have been in place to improve outcomes in dialysis patients, new emphasis is being placed on better management of patients who are pre-end-stage renal disease (pre-ESRD)-patients with chronic kidney disease (CKD). Spearheaded by the National Kidney Foundation, the National Institute of Health, and the nephrology community at large, an effort is underway to improve the care of patients with kidney disease. We hope that improvement in health and outcomes of patients with kidney disease will be optimized through attention to care before the development of advanced renal disease. Cardiovascular disease (CVD) is an important comorbidity of chronic kidney disease, and reducing cardiovascular events in this population is an important goal for the people who care for chronic kidney disease patients. In this article, we review the available literature regarding certain risk factors for cardiovascular disease: proteinuria, hyperglycemia, hypertension, homocysteine, hyperlipidemia, and inflammation. When possible, recommendations for treatment are provided based on the information reviewed.