Plasma C-reactive protein in hemodialysis patients: a cross-sectional, longitudinal clinical survey

Factors Associated With Short-Term Complications After Percutaneous Endoscopic Gastrostomy Tube Insertion: A Retrospective Cohort Study

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) tube placement is generally safe but is associated with a range of complications. Minor complications include infections, granuloma formation, leakage, and blockages, while major complications encompass aspiration pneumonia, hemorrhage, and more serious conditions such as necrotizing fasciitis and colonic fistula.

AIM

This study aimed to assess the rate of short-term complications within one month of endoscopic PEG insertion, focusing on their correlation with patient characteristics.

METHODOLOGY

This retrospective cohort study analyzed data from patients who underwent PEG insertion between January 2020 and December 2022. It evaluated the incidence of complications in relation to variables such as the indication for the procedure, the patient's immune status, albumin and CRP levels, and the setting of the procedure (inpatient vs. outpatient).

RESULTS

The study included 121 patients, with a mean age of 69.73 years, comprising 71 males (58.7%) and 50 females (41.3%). Neurological indications accounted for 64.5% of the cases. Notably, 67.8% of the patients were immunocompromised. Within 30 days of PEG insertion, 16.5% experienced complications, including GI bleeding (4.1%), infection at the PEG site (11.6%), and peritonitis (0.8%). Complications were significantly higher in immunocompromised patients and those with non-neurological indications. Higher serum albumin and lower CRP levels were associated with fewer complications, though the association was not statistically significant.

CONCLUSION

The study highlights that gastrostomy site infection is the most common short-term complication following PEG insertion. Immune status and the reason for PEG insertion emerged as key factors influencing the likelihood of complications.

Prevalence of chronic pain in hemodialysis patients and its correlation with C-reactive protein: a cross-sectional study

End-stage renal disease (ESRD) is a common chronic disease worldwide that requires hemodialysis. Patients may face chronic pain and poor quality of life. Therefore, a better understanding of these variables in hemodialysis patients is essential to provide a good intervention. We aim to determine how common chronic pain is in hemodialysis patients and its correlation with sociodemographics, C-reactive protein (CRP), calcium, phosphorus, albumin, and parathyroid hormone. A cross-sectional study of hemodialysis patients was conducted in Palestine. Data collection took place between November 2020 and May 2021. We used the brief pain inventory score to assess chronic pain, and lab tests detected CRP levels. Data were collected using a convenience sampling technique. There were two hundred sixty-one patients in the present study. The mean age of the patients was 51 years, with 63.6% being men. 47.1% of them reported having chronic pain. Gender (p = 0.011), social status (p = 0.003), educational status (p = 0.010), and number of chronic diseases (p = 0.004) indicated a significant relationship with the severity score of pain. Furthermore, sex (p = 0.011), social status (p = 0.003), and number of chronic diseases (p = 0.002) were significantly associated with the pain interference score. Additionally, Person's test indicated significant correlations between CRP and pain severity (p < 0.001) and with pain interference (p < 0.001). Albumin was significantly and negatively correlated with pain severity (p = 0.001) and pain interference (p < 0.001). Multiple linear regression analysis revealed that patients who had a higher CRP level and many chronic diseases were more likely to have a higher pain severity score. However, pain severity was the only predictor for pain interference. Our results suggest that there is a significant correlation between the existence of chronic pain in hemodialysis patients and increased CRP levels. However, further investigations are needed with a larger number of patients in more than one dialysis unit to confirm this correlation and management of chronic pain in patients with HD.

Association of dialysis-related amyloidosis with lower quality of life in patients undergoing hemodialysis for more than 10 years: The Kyushu Dialysis-Related Amyloidosis Study

BACKGROUND

Dialysis-related amyloidosis (DRA) commonly develops in patients undergoing long-term dialysis and can lead to a decline in activities of daily living and quality of life (QOL), mainly owing to orthopedic complications.

METHODS

First, we determined utility scores of the EuroQol 5-Dimensions 3-Levels (EQ-5D-3L) questionnaire in 1,323 patients with DRA who had undergone dialysis for more than 10 years and compared the score between those with and without DRA. Second, a 2-year follow-up was also performed, in which patients were divided into three groups: those complicated by DRA from the beginning, those with newly developed DRA within the 2-year period, and those not complicated by DRA throughout the survey period; changes in the EQ-5D-3L utility score were compared. In the group already complicated by DRA at the survey baseline, changes in the EQ-5D-3L utility score were compared according to the dialysis treatment method.

RESULTS

A total of 1,314 and 931 patients were included in the first and second studies, respectively. EQ-5D-3L utility scores among patients diagnosed with DRA were significantly lower than scores in those not diagnosed with DRA. The reduction in the EQ-5D-3L utility score over the 2-year follow-up was significantly greater in patients newly complicated by DRA during the follow-up period after enrollment but not in those complicated by DRA from the beginning, as compared with patients not complicated by DRA throughout the survey period. The reduction in utility score tended to be lower in patients routinely treated with a β2-microglobulin adsorption column than in untreated patients with DRA.

CONCLUSION

Complication by DRA in patients undergoing long-term hemodialysis was significantly associated with a decline in QOL.

Platelets: Peripheral Biomarkers of Dementia?

Dementia continues to be the most burdening neurocognitive disorder, having a negative impact on the lives of millions. The search for biomarkers to improve the clinical diagnosis of dementia is ongoing, with the focus on effective use of readily accessible peripheral markers. In this review, we concentrate on platelets as biomarkers of dementia and analyze their potential as easily-accessible clinical biomarkers for various subtypes of dementia. Current platelet protein biomarkers that have been investigated for their clinical utility in the diagnosis of dementia, in particular Alzheimer's disease, include amyloid-β protein precursor (AβPP), the AβPP secretases (BACE1 and ADAM10), α-synuclein, tau protein, serotonin, cholesterol, phospholipases, clusterin, IgG, surface receptors, MAO-B, and coated platelets. Few of them, i.e., platelet tau, AβPP (particularly with regards to coated platelets) and secreted ADAM10 and BACE1 show the most promise to be taken forward into clinical setting to diagnose dementia. Aside from protein biomarkers, changes in factors such as mean platelet volume have the potential to play a very specific role in both the dementia diagnosis and prognosis. This review raises a number of research questions for consideration before application of the above biomarkers to routine clinical setting. It is without doubt that there is a need for more clarification on the effects of dementia on platelet morphology and protein content before these changes can be clinically applied as dementia biomarkers and explored further in differentiating distinct dementia subtypes.

Malnutrition, inflamation and atherosclerosis (MIA syndrome) in patients with end stage renal disease on maintenance hemodialysis (a single centre experience)

BACKGROUND

Inflammation and malnutrition play an important role in endothelial dysfunction, atherosclerosis and excessive cardiovascular morbidity and mortality in ESRD patients AIM OF THE STUDY: The primary objective is to determine the prevalence of inflammation, malnutrition and atherosclerosis in patients on maintenance haemodialysis. Secondary objective was to determine the association for atherosclerosis with inflammation and malnutrition.

PATIENT AND METHODS

One hundred and one adult patients with end stage renal disease on maintenance haemodialysis who are met with the exclusion criteria were enrolled in this cross sectional study from haemodialysis unit of Baghdad teaching hospital over the period of July/2015 - June 2016. All patients were thoroughly examined and many variables were evaluated (age, gender, blood pressure, diabetes mellitus, serum lipid profile, smoking habits, serum albumin, CRP, calcium, Phosphate, Parathyroid hormone and haemoglobin measurements). All patients underwent a carotid Doppler ultrasound study.

RESULTS

Atherosclerosis was present in 65.3%: 58.4% of patients had malnutrition and 43.6% had inflammation. The association for atherosclerosis and high CRP and low serum albumin is strong and independent of other atherosclerosis risk factors. There is significant inverse and independent correlation between CRP and albumin.

CONCLUSION

Inflammation (high serum CRP) and malnutrition (low serum albumin) in patients on haemodialysis are significantly associated with carotid atherosclerosis. Inflammation was more prevalent in the malnourished patients than in those with normal nutritional status.

NT-proBNP: is it a more significant risk factor for mortality than troponin T in incident hemodialysis patients?

Numerous studies have demonstrated that cardiac biomarkers are significant predictors of cardiovascular (CV) and all-cause mortality in ESRD patients, but most of the studies were retrospective or included small numbers of patients, only prevalent dialysis patients, or measured 1 or 2 biomarkers. This study was to analyze the association between 3 cardiac biomarkers and mortality in incident HD patients. A prospective cohort of 864 incident HD patients was followed for 30 months. Based on the median values of baseline NT-proBNP, cTnT, and hsCRP, the patients were divided into "high" and "low" groups, and CV and all-cause mortality were compared between each group. Additionally, time-dependent ROC curves were constructed, and the NRI and IDI of the models with various biomarkers were calculated. The CV survival rates were significantly lower in the "high" NT-proBNP and cTnT groups compared to the corresponding "low" groups, while there was no significant difference in CV survival rate between the 2 hsCRP groups. However, all-cause mortality rates were significantly higher in all 3 "high" groups compared to each lower group. In multivariate analyses, only Ln NT-proBNP was found to be an independent predictor of mortality. Moreover, NT-proBNP was a more prognostic marker for mortality compared to cTnT. In conclusion, NT-proBNP is the biomarker that results in the most added prognostic value on top of traditional risk factors for CV and all-cause mortality in incident HD patients.

Improvements in renal replacement therapy practice patterns in estonia

Background

The clinical performance indicators (CPI) are important tools to assess and improve the quality of renal replacement therapy (RRT). The aim of the current study was to compare the results of a longitudinal set of CPI in RRT patients and to determine the extent to which the guidelines for anaemia, calcium phosphate management and other CPI are met in Estonian renal centres.

Methods

A long-term retrospective, observational, cross-sectional CPI analysis was undertaken in RRT patients from 2007 to 2011. The following CPI set of well-designed measures based on good evidence was analysed: anaemia management variables, laboratory analyses of mineral metabolism, nutritional status variables and dialysis adequacy variables.

Results

Relatively small changes in the analysed mean CPI values were noticed during the study period. In the course of the study, we noticed an improvement in anaemia control, but not all centres achieved the standard of >80% of the dialysis patients with a haemoglobin (Hb) level >100 g/l. There was a trend of decreasing Hb concentrations below 125 g/l in both haemodialysis (HD) and peritoneal dialysis (PD) patients. In 2011, hyperphosphataemia was present in 58% of the HD and 47% of the PD patients, whereas centre differences varied between 50 and 60% of both the HD and PD patients. HD adequacy was achieved in 77% of the HD patients.

Conclusion

An improvement in the data collection was noticed, and the analysis of CPI allows renal centres to assess and compare their practices with others. The collection and evaluation of CPI of RRT patients is an important improvement and significantly increases the awareness of nephrologists.

Association between depression, nutritional status, and inflammatory markers in peritoneal dialysis patients

BACKGROUND

To investigate the relationship between depression, nutritional status, and inflammatory markers in patients on peritoneal dialysis (PD).

PATIENTS AND METHODS

This prospective study included 40 PD patients and 20 healthy people. The severity of depressive symptoms was assessed using the Beck depression inventory, the Hamilton depression rating scale, and the Hamilton anxiety rating scale. The depressive patients received antidepressant drug for 8 weeks. Blood samples were taken before and after antidepressant treatment for the high-sensitive C-reactive protein (hs-CRP), interleukin (IL)-1, IL-6, and tumor necrosis factor-α (TNF-α) levels.

RESULTS

Ten (25%) of the 40 PD patients had depression. No significant difference was determined between depressive patients and nondepressive patients. The mean erythrocyte sedimentation rate was higher in depressive patients. There was no significant difference for other inflammation parameters, including hs-CRP, TNF-α, IL-1, and IL-6, between depressive patients and nondepressive patients. In the depressive patients, we did not observe any significant change in nutritional parameters after antidepressant treatment. When we evaluated inflammation parameters of the depressive patients before and after antidepressant treatment, only IL-1 and IL-6 levels were significantly increased after antidepressant treatment.

CONCLUSION

The depressive disorder in PD patients is a common psychopathology and has no significant effects on nutritional status and inflammation.

Association of malnutrition-inflammation complex and responsiveness to erythropoiesis-stimulating agents in long-term hemodialysis patients

BACKGROUND

Protein-energy wasting, inflammation and refractory anemia are common in long-term hemodialysis patients. A decreased responsiveness to erythropoiesis-stimulating agents (ESA) is often the cause of the refractory anemia. We hypothesized that the malnutrition-inflammation complex is an independent predictor of decreased responsiveness to ESAs in hemodialysis patients.

METHODS

This cohort study of 754 hemodialysis patients was examined for an association between inflammatory and nutritional markers, including the malnutrition-inflammation score (MIS) and responsiveness to ESA. Cubic spline models were fitted to verify found associations.

RESULTS

The mean (±SD) age of patients was 54 ± 15 years, 53% were diabetic and 32% blacks. MIS was worse in the highest quartile of ESAs responsiveness index (ERI, ESA dose divided by hemoglobin) when compared with 1st quartile (6.5 ± 4.5 versus 4.4 ± 3.4; P < 0.001). Both C-reactive protein (log CRP) (β = 0.19) and interleukin-6 (log IL-6) (β = 0.32) were strong and independent predictors of ERI using multivariate linear regression. Serum albumin (β = -0.30) and prealbumin levels (β = -0.14) were inversely associated with ERI. Each 1 SD higher MIS, higher CRP and lower albumin were associated with 86, 44 and 97% higher likelihood of having highest versus three lowest ERI quartiles in fully adjusted models [odds ratio (and 95% confidence interval) of 1.86 (1.31-2.85), 1.44 (1.08-1.92) and 1.97 (1.41-2.78)], respectively. Cubic splines confirmed the continuous and incremental nature of these associations.

CONCLUSIONS

Malnutrition-inflammation complex is an incremental predictor of poor responsiveness to ESAs in hemodialysis patients. Further studies are needed to assess whether modulating inflammatory or nutritional processes can improve anemia management.

Relationship between depression and proinflammatory cytokine levels in hemodialysis patients

AIM

To evaluate the presence of the relationship between depression and proinflammatory cytokine levels in hemodialysis (HD) patients.

METHODS

The study included 40 HD patients and 20 healthy controls. All participants were evaluated for the presence of depression using the structured clinical interview based on criteria defined by Diagnostic and statistical manual mental disorders (Fourth Edition, Text Revision) Axis I disorders. The severity of depressive symptoms was assessed using the Beck Depression Inventory, the Hamilton Depression Rating Scale, and the Hamilton Anxiety Rating Scale. The depressive patients received antidepressants for 8 weeks. Blood samples were taken at baseline and after 8 weeks of antidepressant treatment for interleukin-1 (IL-1), IL-6, and tumor necrosis factor-α (TNF-α) levels.

RESULTS

A total of 9 (22.5%) of the 40 HD patients had depression. IL-1, IL-6, and TNF-α levels were significantly higher in HD patients compared with that in the control group, but were not significantly different between HD patients with and without depression. In the depressive patients, we observed no significant difference in proinflammatory cytokine levels after antidepressant treatment. The psychometric measurements in depressive patients decreased significantly after antidepressant treatment.

CONCLUSION

We observed that depression is a common psychiatric disorder and has no significant effect on proinflammatory cytokine levels in HD patients; no important improvement in cytokine levels was observed after antidepressant therapy.

Elevation of Pro-Inflammatory Cytokines, C-Reactive Protein and Cardiac Troponin T in Chronic Renal Failure Patients on Dialysis

Chronic renal failure (CRF) patients suffer from a chronic inflammation. They are at increased risk of cardiovascular disease. In order to investigate this inflammatory process and cardiovascular risk factors associated with haemodialysis (HD) and peritoneal dialysis (PD), we compared serum/plasma pro-inflammatory cytokines, C-reactive protein (CRP), and cardiac troponin T (cTnT) of 146 CRF patients treated or not treated with PD or HD. Serum cytokines and CRP as well as plasma cTnT were measured by enzyme-linked immunosorbent assay, chemiluminescence immunoassay, and electrochemiluminescence immunoassay, respectively. Results indicated that serum interleukin (IL)-18 concentrations were significantly higher in PD and low creatinine clearance pre-dialysis CRF (LCC) patients than HD patients (both p < 0.05). IL-6 and tumour necrosis factor (TNF)-alpha concentrations were significantly higher in PD patients than LCC patients (both p < 0.01). Serum hsCRP and plasma cTnT in HD were significantly higher than LCC (both p < 0.01). The elevation of pro-inflammatory cytokines should play an important role in the chronic inflammation and increased cardiovascular risk of CRF patients on dialysis. We are evaluating further the diagnostic and prognostic applications of pro-inflammatory cytokines and biochemical inflammatory markers for these patients.

Inflammatory syndrome in patients on hemodialysis

Mortality is markedly elevated in hemodialysis (HD) patients. Between 30 and 50% of prevalent patients have elevated serum levels of inflammatory markers such as C-reactive protein and IL-6. The presence of inflammation, chronic or episodic, has been found to be associated with increased mortality risk. The causes of inflammation are multifactorial and include patient-related factors, such as underlying disease, comorbidity, oxidative stress, infections, obesity, and genetic or immunologic factors, or on the other side, HD-related factors, mainly depending on the membrane biocompatibility and dialysate quality. The adequate knowledge of these causes and their prevention or treatment if possible may contribute to improving the inflammatory state of patients who are on HD and possibly their mortality.

Mortality risk for patients receiving hemodiafiltration versus hemodialysis: European results from the DOPPS

Hemodiafiltration (HDF) is used sporadically for renal replacement therapy in Europe but not in the US. Characteristics and outcomes were compared for patients receiving HDF versus hemodialysis (HD) in five European countries in the Dialysis Outcomes and Practice Patterns Study. The study followed 2165 patients from 1998 to 2001, stratified into four groups: low- and high-flux HD, and low- and high-efficiency HDF. Patient characteristics including age, sex, 14 comorbid conditions, and time on dialysis were compared between each group using multivariate logistic regression. Cox proportional hazards regression assessed adjusted differences in mortality risk. Prevalence of HDF ranged from 1.8% in Spain to 20.1% in Italy. Compared to low-flux HD, patients receiving low-efficiency HDF had significantly longer average duration of end-stage renal disease (7.0 versus 4.7 years), more history of cancer (15.4 versus 8.7%), and lower phosphorus (5.3 versus 5.6 mg/dl); patients receiving high-efficiency HDF had significantly more lung disease (15.5 versus 10.2%) and received a higher single-pool Kt/V (1.44 versus 1.35). High-efficiency HDF patients had lower crude mortality rates than low-flux HD patients. After adjustment, high-efficiency HDF patients had a significant 35% lower mortality risk than those receiving low-flux HD (relative risk=0.65, P=0.01). These observational results suggest that HDF may improve patient survival independently of its higher dialysis dose. Owing to possible selection bias, the potential benefits of HDF must be tested by controlled clinical trials before recommendations can be made for clinical practice.

UNRESOLVED ISSUES IN DIALYSIS: Ultrapure Dialysate: Facts and Myths

During hemodialysis, blood comes in contact with a large volume of dialysate. Since the purity of dialysate has been linked to acute and long-term complications in hemodialysis patients, the limit of bacterial and endotoxin contamination has been reduced in recent years. Questions have been raised as to whether ultrapure dialysate is required to prevent such complications; in particular, the chronic inflammatory status frequently found in chronically hemodialyzed patients. In vivo and in vitro data suggest that cytokine stimulation in the blood depends on the concentration of bacteria or endotoxin in the dialysate and on the endotoxin permeability of the dialysis membrane. It is not proven whether ultrapure dialysate reduces significantly proinflammatory cytokine generation compared with standard dialysate within the limits of recent recommendations, if rather impermeable dialysis membranes are used. Cuprophane membranes are more permeable to cytokine-inducing substances compared with synthetic membranes such as polysulfone and polyamide. Clinical reports have also attempted to link several acute and chronic complications of hemodialysis to dialysate purity. To date, however, there is no large randomized clinical trial demonstrating that ultrapure dialysate significantly reduces biomarkers of inflammation and other consequential putative complications, including dialysis-related amyloidosis, erythropoietin requirement, and cardiovascular morbidity and mortality. In conclusion, based on the existing clinical data, ultrapure dialysate is recommended in the setting of suboptimal bacteriologic quality of standard dialysate and the use of permeable dialysis membranes.

The interaction of vascular inflammation and chronic kidney disease for the prediction of long-term death after percutaneous coronary intervention

BACKGROUND

Patients with chronic kidney disease frequently have worse outcomes following percutaneous coronary intervention (PCI) compared to patients with normal renal function. Furthermore, they more commonly have elevated serum markers of inflammation, which may be either directly or indirectly associated with a state of accelerated atherosclerosis. We sought to assess the relationship among glomerular filtration rate (GFR), systemic inflammation, and long-term death after PCI.

METHODS

In patients undergoing PCI, the intensity of vascular inflammation was measured using baseline ultrasensitive C-reactive protein (us-CRP), and GFR was calculated using the Modification of Diet in Renal Disease formula. Their association with long-term death was compared using multivariate Cox regression analysis including an interaction element for us-CRP and GFR, baseline clinical, biochemical, and angiographic variables.

RESULTS

In 4522 patients (mean age 65 +/- 11 years) having undergone PCI, 332 (7.3%) deaths occurred over the median duration of follow-up of 20.1 months (interquartile range 8.5-31.3 months). The mean GFR was 77 +/- 33 mL/min per 1.73 m2 with a median us-CRP of 3.75 mg/L (interquartile range 1.5-10.1 mg/L). Both increasing levels of CRP (log rank P < .001) and decreasing levels of GFR were univariate predictors of long-term death (P < .001). In a multivariate model, both GFR and us-CRP retained independent predictive value for long-term death.

CONCLUSION

Although baseline us-CRP and GFR are both independent predictors of long-term death after PCI, in concert, they impart a markedly exaggerated hazard of mortality.

Serum C-reactive Protein Level Is Associated with Renal Function and It Affects Echocardiographic Cardiovascular Disease in Pre-Dialysis Patients

BACKGROUND

Relevance of serum CRP for morbidity and mortality in pre-dialysis patients has not been assessed extensively. The aim of this study was to determine the incidence of elevated serum CRP in pre-dialysis patients and to identify the factors that associate with serum CRP. We were also evaluated the effects of serum CRP on cardiovascular disease, anemia, and nutritional markers.

METHODS

One hundred and eight pre-dialysis patients with a mean creatinine clearance (CrCl) of 30.1 ml/min were included in the study. Data collected from each patient included demographics, co-morbidity, medications, blood pressures, blood biochemistry including serum CRP, renal function, and echocardiography.

RESULTS

Serum CRP was elevated (>5 mg/l) in 43 patients (39.8%). There was a negative correlation between serum CRP and CrCl (r = -0.370, p < 0.001). CrCl was the unique independent factor affecting serum CRP. Serum CRP was an independent factor affecting left ventricular mass index, fractional shortening, serum albumin and hematocrit in multivariate analyses.

CONCLUSIONS

Prevalence of elevated serum CRP in pre-dialysis patients is high. Reduced renal clearance of CRP and/or cytokines may contribute to the inflammatory status. Elevated serum CRP is an important cause of morbidity in pre-dialysis patients.

C-Reactive Protein Levels in Patients on Maintenance Hemodialysis: Reliability and Reflection on the Utility of Single Measurements

BACKGROUND

Single C-reactive protein (CRP) values have been associated with death and cardiovascular disease in dialysis patients. We prospectively obtained multiple CRP values in stable patients, hypothesizing that values would remain stable in the absence of disease and that a single CRP value would be a reliable marker of risk.

METHODS

Four CRP values per week for three consecutive weeks were obtained in 10 clinically stable patients receiving conventional HD. Using prespecified cutoffs of 2.2 and 4.4 mg/l, the frequency of risk misclassification relative to the lowest CRP value obtained was determined. Within and between patient variability was also calculated.

RESULTS

The median age was 54 years, and the average duration of dialysis was 41 months. Nine out of ten patients had at least one abnormal CRP value (>2.2 mg/l), six had all values elevated, and seven had an abnormal median CRP. The overall coefficient of reliability was 0.63 (95% CI 0.42-0.87). The misclassification rate varied with cutoff, and ranged from 0-83% and 0-58% using upper limit of normal (ULN) and twice ULN, respectively. The within patient variability was 0.37 for the entire cohort, and 0.33 when three patients with intercurrent acute inflammation were excluded.

CONCLUSIONS

CRP exhibits short term variability in HD patients, resulting in a risk of misclassification depending on sampling time and chosen cutoff point. Single CRP values must be interpreted with caution, and multiple measurements, or use of other biomarkers, should be considered.

Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of determination of procalcitonin (PCT) and C-reactive protein (CRP) levels for the diagnosis of bacterial infection. The analysis included published studies that evaluated these markers for the diagnosis of bacterial infections in hospitalized patients. PCT level was more sensitive (88% [95% confidence interval [CI], 80%-93%] vs. 75% [95% CI, 62%-84%]) and more specific (81% [95% CI, 67%-90%] vs. 67% [95% CI, 56%-77%]) than CRP level for differentiating bacterial from noninfective causes of inflammation. The Q value for PCT markers was higher (0.82 vs. 0.73). The sensitivity for differentiating bacterial from viral infections was also higher for PCT markers (92% [95% CI, 86%-95%] vs. 86% [95% CI, 65%-95%]); the specificities were comparable (73% [95% CI, 42%-91%] vs. 70% [95% CI, 19%-96%]). The Q value was higher for PCT markers (0.89 vs. 0.83). PCT markers also had a higher positive likelihood ratio and lower negative likelihood ratio than did CRP markers in both groups. On the basis of this analysis, the diagnostic accuracy of PCT markers was higher than that of CRP markers among patients hospitalized for suspected bacterial infections.

The effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients

The aim of this study was to investigate the effects of antidepressant treatment on serum cytokines and nutritional status in hemodialysis patients. Twenty-eight hemodialysis patients with a depressed mood were given 20 mg of fluoxetine for 8 weeks. The degree of depressive symptoms, the serum levels of interleukin-1beta, interleukin-2, interleukin-6, tumor necrosis factor-alpha, c-reactive protein, and markers of nutritional status were assessed at baseline and after treatment. The outcome was assessed in terms of response to treatment (>50% reduction in the score of the Hamilton depression rating scale). Antidepressant treatment decreased the serum level of interleukin-beta1 in both response and nonresponse groups, and increased the serum level of interleukin-6 only in the response group. At baseline, the level of interleukin-6 in the response group was lower than in the nonresponse group. Antidepressant treatment also increased fat distribution significantly in the response group which might have slightly improved the nutritional status. This study suggests that antidepressant treatment improve depressive symptoms and may affect immunological functions and nutritional status in chronic hemodialysis patients with depression.

Dialyser reuse-associated mortality and hospitalization risk in incident Medicare haemodialysis patients, 1998-1999

BACKGROUND

The reuse of haemodialysers has been practiced in the United States for >20 years. We investigated mortality and hospitalization risk according to various reuse practices, testing the hypothesis that outcomes are improved in patients treated with dialysers cleaned with bleach and sterilized with formaldehyde.

METHODS

We studied 1998 and 1999 incident Medicare haemodialysis patients, with follow-up through December 31, 2000 (49 273 patients). Clinical conditions and dialysis therapy were characterized from Medicare claims data. Included were patients who could be linked to a dialysis provider. Demographic characteristics were obtained from the Centers for Medicare and Medicaid Services (CMS) Medical Evidence Report. Mortality information was obtained from the CMS ESRD Death Notification; hospitalization information, from Medicare in-patient claims files. Data on reuse practices were obtained from the annual survey of haemodialysis units conducted by the Centers for Disease Control and Prevention.

RESULTS

Cox regression analyses found no significant differences in mortality or first-hospitalization risk for patients in dialysis units not using bleach as a cleaning agent. Outcomes for patients treated in units using glutaraldehyde did not vary according to use of bleach. In the analysis of first-hospitalization risk, there was no difference according to various germicide/bleach combinations. Overall, there was no significant difference in relative risk of death or in hospitalization risk among the reuse groups (including the no-reuse group).

CONCLUSIONS

For the 1998-1999 period, reuse practices were not associated with a survival advantage or disadvantage. Our findings may reflect the National Kidney Foundation's 1997 introduction of clinical practice guidelines, the intent of which was to bring about increased consistency of care within the dialysis community in the United States.

Biological Reactions Resulting from Endotoxin Adsorbed on Dialysis Membrane: An In Vitro Study

Some types of dialysis membrane are known to adsorb endotoxin (ET). It is suggested that the biocompatibility of dialysis membrane is enhanced by adsorption and inhibition of ET. This study attempts to clarify the membrane-mediated biological reaction of the ET that is adsorbed to a dialysis membrane. After a dialysis circuit was prepared, contaminated dialysate was introduced on the dialysate side of a polyether polymer alloy (PEPA) membrane that adsorbs ET while saline solution or blood were introduced on the blood side, and the difference in ET adsorption between the two set-ups was measured. Further, the side filled with blood was left standing for 2 h, after which the changes in the amount of interleukin 1 receptor antagonist (IL-1Ra) produced from the whole blood were also assayed. Significantly more ET was adsorbed to the dialysis membrane when blood rather than saline was on the other side. In addition, the IL-1Ra production from the dialysis membrane that adsorbed ET was significantly higher. The ET adsorbed to the dialysis membrane may influence a living body even if it does not pass through the membrane. Accordingly, it is difficult to assume that the adsorption of ET to the membrane enhances its biocompatibility.

[Atherosclerosis and uremia: signifance of non-traditional risk factors]

Arteriosclerosis, atherosclerosis and vascular calcification are causally related to the high morbidity and mortality of patients with chronic renal failure. Oxidative stress and carbonyl stress of uremia, dialysis procedure and/or intravenous iron therapy result in AGE (advanced glycation end-product), ALE (advanced lipoxidation end-product) and AOPP (advanced oxidation protein product) formation, favouring together with elevated CRP (C-reactive protein) levels the development of cardiovascular and cerebrovascular complications. Enhanced plasma levels of homocysteine and ADMA (asymmetric dimethylarginine) contribute to this process. In addition, in chronic renal insufficiency hyperphosphatemia and an enhanced calcium x phosphorus ion product are associated with the morbidity and mortality of the patients, particularly in the presence of fetuin deficiency. Phosphorus, AGEs and AOPPs, beside other factors, catalyze the conversion of vascular smooth muscle cells to osteoblast--like cells (particularly in the presence of monocytes/macrophages), resulting in bone matrix protein formation. Other risk factors, such as age, male sex, smoking, hypertension, diabetes, chronic inflammation, insulin resistance or dyslipidemia (enhanced non-HDL-cholesterol) also contribute to the atherosclerotic risk profile of the patient with chronic renal insufficiency. While there is growing understanding of the mechanisms involved in arteriosclerosis, atherosclerosis and vascular calcification in uremia, we are still missing effective therapeutic maneuvers for reduction of excess mortality in uremic 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.

Inflammation in end-stage renal disease: sources, consequences, and therapy

Cardiovascular disease (CVD) remains the main cause of morbidity and mortality in patients with end-stage renal disease (ESRD). Although traditional risk factors are common in ESRD patients, they alone may not be sufficient to account for the high prevalence of CVD in this condition. Recent evidence demonstrates that chronic inflammation, a nontraditional risk factor which is commonly observed in ESRD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. The causes of inflammation in ESRD are multifactorial and, while it may reflect underlying CVD, an acute-phase reaction may also be a direct cause of vascular injury by several pathogenetic mechanisms. Available data suggest that proinflammatory cytokines play a central role in the genesis of both malnutrition and CVD in ESRD. Thus it could be speculated that suppression of the vicious cycle of malnutrition, inflammation, and atherosclerosis (MIA syndrome) would improve survival in dialysis patients. Recent evidence has demonstrated strong associations between inflammation and both increased oxidative stress and endothelial dysfunction in ESRD patients. As there is not yet any recognized, or even proposed, treatment for ESRD patients with chronic inflammation, it would be of obvious interest to study the long-term effect of various anti-inflammatory treatment strategies on the nutritional and cardiovascular status as well as outcome in these patients.

Nutritional status in dialysis patients: a European consensus

BACKGROUND

Malnutrition is common in dialysis patients and closely related to morbidity and mortality. Therefore, assessment of nutritional status and nutritional management of dialysis patients play a central role in everyday nephrological practice.

METHODS

Achieving a consensus on key points relating to pathogenesis, clinical assessment, and nutritional management of dialysis patients.

RESULTS

The assessment of nutritional status should be based on clinical assessment and biochemical parameters, including history of weight loss, per cent standard weight, body mass index, muscle mass, subcutaneous fat mass, and plasma albumin, creatinine, bicarbonate and cholesterol. Co-morbid conditions should be assessed and C-reactive protein (CRP) measured--as a marker of inflammation--as there is a close relation between malnutrition, on one side, and co-morbid conditions and inflammation on the other. For a more detailed assessment, subjective global assessment of nutritional status is a well-validated tool, and dual-energy X-ray absorptiometry (DEXA) is a useful method for routine assessment of lean body mass. Anthropometric methods are also useful. They are cheap and easy to apply, although less precise than DEXA. The recommended daily protein intake is at least 1.2 g/kg standard body weight and the energy intake 35 kcal/kg standard body weight (BW), in patients <60 years, and 30 kcal/kg standard BW in patients >60 years. The standard bicarbonate level should be at least 22 mmol/l. If CRP is >10 mg/l, it is important to seek and treat the underlying cause. Adequate dialysis (for haemodialysis: Kt/V >1.2) should be ensured and, although no definite evidence of the importance of dialysis water quality is available, the opinion of the authors is that the water quality should be high. The role of the biocompatibility of the dialysis membrane is still not clear. The dietitian plays a pivotal role in the nutritional care of dialysis patients, and patients should be provided with dietary counselling from the start of substitutive treatment in order to meet the recommended nutritional intakes. Dietary counselling can also play an important role in an integrated treatment of hyperphosphataemia, although most patients will also need phosphate binders if they have an adequate protein intake.

CONCLUSION

Malnutrition assessment and treatment is a great challenge for nephrological care. Achieving evidence-based consensus can help in implementing the progress of knowledge in clinical practice.

Vascular calcifications as a footprint of increased calcium load and chronic inflammation in uremic patients: a need for a neutral calcium balance during hemodialysis?

Cardiovascular complications caused by an accelerated atherosclerotic disease represent the largest single cause of mortality in chronic renal failure patients. The rapidly developing atherosclerosis of the uremic syndrome appears to be caused by a synergism of different mechanisms, such as malnutrition, oxidative stress and genetic factors. Recent studies provide evidence that chronic inflammation plays an important role in the pathogenesis of cardiovascular diseases. Hyperphosphatemia and an increased calcium-phosphate ion product have also been associated with an increased risk of death. Cardiovascular calcifications secondary to increases in phosphate and calcium load in dialysis patients might exert an important contribution to the excess cardiovascular mortality and morbidity in dialysis patients. Elevated serum levels of plasma C-reactive protein (CRP) are associated with the extent and severity of the atherosclerotic processes as well as with an increased risk of experiencing myocardial infarction and sudden cardiac death in apparently healthy subjects. In patients affected by pre-dialytic renal failure increased levels of CRP and IL-6 were recorded in 25% of our population; CRP and IL-6 were inversely related with renal function. These data suggest the activation--even in the predialytic phase of renal failure--of mechanisms known to contribute to the enhanced cardiovascular morbidity and mortality of the uremic syndrome. In recent years we have investigated the hypothesis that the chronic inflammatory state of the uremic patient could be at least in part due to the dialytic technique. We have shown that the increase of CRP in stable dialysis patients may be due to the stimulation of monocyte/macrophage by backfiltration of dialysate contaminants. During conventional dialysis, a positive calcium balance and a concomitant inflammatory state may act as cofactors in the development of cardiovascular calcifications. We suggest that this hypothesis should be verified by clinical studies. A reevaluation of the ideal calcium levels in the dialysate is warranted: a neutral intradialytic calcium balance is probably more appropriate, although not easily attainable.

C reactive protein in patients with chronic renal diseases

Base-line serum levels of plasma C-reactive protein (CRP) are predictive of future myocardial infarction and sudden cardiac death in apparently healthy subjects, suggesting the hypothesis that chronic inflammation might be important in the pathogenesis of atherothrombosis. CRP production is mediated by several inflammatory mediators: interleukin 6 (IL-6) is currently felt to be the major cytokine influencing the acute phase response. CRP and other acute phase proteins are elevated in dialysis patients and cardiovascular diseases represent the single largest cause of mortality in chronic renal failure patients. Little information is available, however regarding CRP and IL-6 plasma levels in pre-dialysis renal failure. Plasma CRP was determined by a modification of the laser nephelometry technique; IL-6 by immunoassay (RD System); and fibrinogen, serum albumin, cholesterol, triglycerides, hematocrit, white blood cell count, erythrocytic sedimentation rate (ESR) and urinary protein levels by standard laboratory techniques. Results were obtained in 102 chronic pre-dialysis patients whose mean age was 53+/-5.8 years with a mean creatinine clearance (C(Cr)) of 52+/-37 mL/min). CRP was greater than 5 mg/L in 25% of the global population. CRP and IL-6 were 4.0+/-4.6 mg/L and 5.8+/-5.6 pg/mL, respectively and were not significantly correlated (r=0.11, p=n.s.). CRP and IL-6 were however related with renal function (CRP versus C(Cr) r=-0.40 p <0.001; IL- 6 versus C(Cr) r=-0.45; p <0.001). When patients were divided in two groups according to renal function, CRP resulted 7.4+/-6.3 mg/L in the group of patients with a C(Cr) lower than 20 mL/min (n=32) and 2.76+/-4.35 in the group of patients with a C(Cr) higher than 20 mL/min (n = 70) (p <0.0001). CRP and IL-6 were positively related with ESR (r=0.32 and 0.46 respectively). Serum albumin levels were not significantly different in the two groups of patients (3.2+/-0.4 versus 3.0+/-0.5 g/dL). CRP and serum albumin were not significantly related (r=0.17). CRP and IL-6 correlated positively with ESR (r=0.32 and 0.46 respectively). In pre-dialysis patients we have demonstrated an increase in both CRP and IL-6 that occurs as renal function decreases. These data provided evidence of the activation - even in the predialysis phase of renal failure - of mechanisms known to contribute to the enhanced cardiovascular morbidity and mortality of the uremic syndrome.

End-stage renal disease, atherosclerosis, and cardiovascular mortality: is C-reactive protein the missing link?

In uremic patients, the morbidity and mortality of cardiovascular disease are substantially higher than in the general population. This has led to the formulation of an 'accelerated atherogenesis' hypothesis in uremic patients and has been commonly linked with the metabolic alterations associated with uremia. Advancement in the understanding of the pathogenesis of atherosclerotic vascular disease now suggests a central contribution of inflammation to atherogenesis, with involvement of a number of key mediators and markers of the inflammatory process. Recent epidemiological data have documented associations between C-reactive protein (CRP), the prototypical acute phase response protein, and cardiovascular disease in general population. Given the lipoprotein binding and complement activation functions of CRP and its localization in atherosclerotic vessels, there is a strong likelihood that CRP may be involved in the atherosclerotic process. The uremic state is associated with an altered immune response, which is associated with elevated proinflammatory cytokine levels. CRP concentrations are increased in a significant proportion of end-stage renal disease patients and have been associated with certain clinical outcome measures, including all-cause and cardiovascular mortality. This review outlines the evidence linking CRP with atherosclerosis and proposes that elevated CRP concentrations may be involved in the initiation and progression of accelerated atherosclerosis in uremia.

A Comparative Study of C-Reactive Protein Plasma Levels in Patients on Hemodialysis and Peritoneal Dialysis

In dialysis patients, C-reactive protein (CRP), a well-recognized marker of inflammation, predicts mortality. Higher levels have been described in hemodialysis (HD) patients as compared with peritoneal dialysis (PD) patients. Our aim was to determine, based on CRP plasma levels, the degree of inflammation in HD patients using low-permeability polysulfone membranes and relatively pure dialysate, and that in PD patients. A secondary objective was to study factors associated with hypoalbuminemia and inflammation in both populations. We studied 69 stable patients on dialysis (32 on HD and 37 on PD). The mean age was 69.9 ± 8.2 years, and the mean time on dialysis was 27 months. The two populations were comparable for overall and cardiovascular comorbidities. Nephelometry was used to measure CRP plasma levels (normal levels < 0.6 mg/dL). The Kt/V_urea , corrected for residual renal clearance, and the equivalent of protein nitrogen appearance (PNA) were also calculated. Of the patients studied, 53% showed CRP plasma levels higher than 0.6 mg/dL; in 36%, the levels were higher than 1 mg/dL. No significant differences in these percentages were noted between the two dialysis groups. Patients with CRP levels higher than 1 mg/dL showed lower serum albumin, iron, hemoglobin, and transferrin levels, and higher ferritin values and leukocyte counts. Under logistic regression analysis, CRP levels higher and lower than 1 mg/dL were significantly associated with serum albumin [p = 0.01; odds ratio (OR): 0.15], iron (p = 0.006; OR: 0.96), transferrin (p = 0.004; OR: 0.97), and hemoglobin (p = 0.02; OR: 0.67). Serum albumin levels were significantly lower in PD patients. Under regression analysis, serum albumin levels correlated with cholesterol (r: 0.25; p = 0.04), serum iron (r: 0.5; p = 0.0001), transferrin (r: 0.3; p = 0.015), ultrafiltration capacity (r: 0.42; p = 0.008), and CRP values above 0.6 mg/dL (r: -0.65; p = 0.001). In conclusion, the frequent elevation of CRP plasma levels observed in both HD and PD patients suggests the presence of a silent inflammatory state. Hemodialysis performed with biocompatible, low-permeability membranes is not associated with higher CRP plasma levels than those seen in PD. In both groups, hypoalbuminemia is related to CRP level. Levels of serum albumin, slightly lower in PD patients, are also related to peritoneal ultrafiltration capacity.

C-reactive protein as a marker of chronic inflammation in uremic patients

Cardiovascular complications caused by an accelerated atherosclerotic disease represent the largest single cause of mortality in chronic renal failure patients. The rapidly developing atherosclerosis of the uremic syndrome appears to be caused by a synergism of different mechanisms, such as malnutrition, oxidative stress and genetic factors. Recent studies provide evidence that chronic inflammation plays an important role in the pathogenesis of cardiovascular diseases. Elevated serum levels of plasma C-reactive protein (CRP) are associated with an increased risk of experiencing myocardial infarction and sudden cardiac death in apparently healthy subjects. Several recently published papers have confirmed this strong association between CRP and the extent and severity of the atherosclerotic processes. In patients affected by predialytic renal failure, increased levels of CRP and interleukin (IL)-6 were recorded in 25% of our population; CRP and IL-6 were inversely related with renal function. These data suggest the activation - even in the predialytic phase of renal failure - of mechanisms known to contribute to the enhanced cardiovascular morbidity and mortality of the uremic syndrome. In recent years we have investigated the hypothesis that the chronic inflammatory state of the uremic patient could at least in part be due to the dialytic technique. We provide evidence suggesting that the increase of CRP in stable dialytic patients may be due to the stimulation of monocyte/macrophage by backfiltration of dialysate contaminants.

The link of biocompatibility to cytokine production

Recent studies suggest that chronic inflammation plays a role in the pathogenesis of cardiovascular disease. Cytokines released from jeopardized tissues stimulate the liver to synthesize acute phase proteins, including C-reactive protein (CRP). Baseline levels of CRP in apparently healthy persons or in persons with unstable angina constitute an independent risk factor for cardiovascular events. More recently, it has been suggested that CRP is useful not only as a marker of the acute phase response, but is also involved in the pathogenesis of the disease. CRP may, in fact, directly interact with the atherosclerotic vessels or ischemic myocardium by activation of the complement system, thereby promoting inflammation and thrombosis. Several studies in uremic patients have implicated CRP as a marker of malnutrition, resistance to erythropoietin, and chronic stimulation in hemodialysis. An increased cytokine production secondary to blood interaction with bioincompatible dialysis components has been reported by several studies; interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), and mainly IL-6 are the three proinflammatory cytokines involved in the pathogenesis of hemodialysis-related disease. We have provided evidence for the occurrence of high CRP and IL-6 levels in chronic dialytic patients exposed to contaminate dialysate and suggest that backfiltration may induce a chronic, slowly developing inflammatory state that may be abrogated by avoiding backfiltration of contaminate dialysate. Therefore, CRP is implicated as a marker linking bioincompatibility associated with backfiltration and increased cytokine production with a clinical state of chronic inflammation.