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Biomedical subjects

Raymond T Krediet

Publications and source records attributed to Raymond T Krediet.

At least 19 recordsLinked to original sources
PubMed2006

Social support predicts survival in dialysis patients.

BACKGROUND: Social support is a consistent predictor of survival, as evidenced in empirical studies in patients with cancer or cardiovascular disease. In the area of renal diseases, this topic has not yet been studied extensively. This study, therefore, aimed to investigate the association between social support and survival for patients on dialysis. METHODS: Between December 1998 and January 2002, 528 incident haemodialysis (HD) and peritoneal dialysis (PD) patients from multiple centres in The Netherlands were consecutively recruited as part of the NECOSAD-2 study. Patients completed the Social Support List (SSL) at 3 months after the start of dialysis. The SSL measured two aspects of social support: interaction and discrepancy. Cox regression analysis was used to estimate all-cause mortality risk from baseline till censor date on 1 January 2005. RESULTS: Perceiving a discrepancy between expected and received social support was associated with increased mortality: social companionship (RR(adj): 1.06, 95% CI: 1.00-1.13), daily emotional support (RR(adj): 1.10, 95% CI: 1.02-1.18), and total support (RR(adj): 1.02, 95% CI: 1.00-1.04). This association was similar for PD and HD patients. Social support (interaction) was not associated with survival, neither in the whole sample nor when stratified by therapy modality. CONCLUSIONS: These results point to the importance of psychosocial risk factors for mortality in patients on dialysis. More efforts are needed to improve support for these patients.

Female↗
PubMed2006

Mineral metabolism and cardiovascular morbidity and mortality risk: peritoneal dialysis patients compared with haemodialysis patients.

BACKGROUND: The K/DOQI guideline for bone metabolism and disease in chronic kidney disease is predominantly based on studies in haemodialysis (HD) patients. However, in clinical practice, this guideline is also applied to peritoneal dialysis (PD) patients. To validate the implementation of this guideline in PD patients, we evaluated the associations between plasma concentrations outside the K/DOQI-targets and the risk of cardiovascular morbidity and mortality in incident PD patients compared with HD patients. METHODS: In a large prospective multicentre study in the Netherlands (The Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), we included patients starting PD or HD between 1997 and 2004. Relative risk of cardiovascular morbidity and mortality were estimated using time-dependent Cox regression modelling. RESULTS: We included 586 PD patients with mean age 52 +/- 15 years (66% males) and 1043 HD patients with mean age 63 +/- 14 years (58% males). Cardiovascular disease (CVD) was the reason for hospitalization in 102 PD and 271 HD patients. In HD patients, the relative risk of CVD-related hospitalization increased with elevated plasma calcium concentrations (hazard ratio: 1.4; 95% CI: 1.1-1.9). Cardiovascular mortality was significantly higher for phosphorus concentrations above the K/DOQI-threshold in PD (2.4; 95% CI: 1.3-4.2) and HD patients (1.5; 95% CI: 1.1-2.1), and for elevated Ca x P in PD (2.2; 95% CI: 1.3-3.8) and HD patients (1.5; 95% CI: 1.1-2.1). CONCLUSIONS: Plasma calcium concentrations above the K/DOQI-threshold increase the relative risk of CVD-related hospitalization in HD patients. Associations with cardiovascular mortality were more pronounced. Both in PD and HD patients with elevated plasma phosphorus and Ca x P concentrations, the cardiovascular mortality risk is increased. Therefore, it seems appropriate to adopt the current guideline in PD patients.

Biomarkers↗
PubMed2006

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.

C-Reactive Protein↗
PubMed2006

Serum troponin T concentration as a predictor of mortality in hemodialysis and peritoneal dialysis patients.

BACKGROUND: Troponin T is a good predictor of all-cause and cardiovascular mortality in cardiac patients. Although it is known that troponin T is an independent risk factor in dialysis patients as well, its prognostic value when measured routinely in clinical practice, particularly in addition to other risk indicators, is unclear. METHODS: A cohort of 847 patients who started dialysis therapy between 1997 and 2001 and participated in a multicenter follow-up study was examined. Clinical data were determined 3 months after the start of dialysis therapy. Patients were followed up until date of death or censoring in November 2003. RESULTS: For patients with troponin T values of 0.05 to 0.10 microg/L, hazard ratio for all-cause mortality was 2.2 (95% confidence interval [CI], 1.7 to 2.8) compared with patients with values less than 0.05 microg/L. For patients with values greater than 0.10 microg/L (11%), hazard ratio was 3.3 (95% CI, 2.5 to 4.5). A survival model with clinical and laboratory risk indicators yielded an area under the curve of 0.81, which did not increase when troponin T level was added to the model. The area under the curve for troponin T level alone was 0.67. No important differences were found between patients on hemodialysis or peritoneal dialysis therapy and between patients with high and low residual renal function. CONCLUSION: Although troponin T level is an independent risk factor for mortality in dialysis patients, it has limited added predictive power as a routine screening test over other clinical risk factors in dialysis patients.

Female↗
PubMed2006

Cystatin C in critically ill patients treated with continuous venovenous hemofiltration.

Assessment of residual renal function in critically ill patients with acute renal failure (ARF) treated with continuous venovenous hemofiltration (CVVH) is difficult. Cystatin C (CysC) is a low-molecular-weight protein (13.3 kDa) removed from the body by glomerular filtration. Its serum concentration has been advocated for assessment of renal function in patients with kidney disease. To investigate whether the removal of CysC by CVVH is likely to influence its serum concentration, concentrations of CysC were measured in 3 consecutive samples in 18 patients with oliguric ARF treated with CVVH (2 L/hr). Samples were taken from the afferent and efferent blood lines and from the ultrafiltrate line. Concentrations of CysC did not change during the time interval studied. The mean serum concentrations of CysC were 2.25+/-0.45 mg/L in the afferent and 2.19+/-0.56 mg/L in the efferent samples (NS); ultrafiltrate concentrations of CysC were 1.01+/-0.45 mg/L. The sieving coefficient of CysC was 0.52+/-0.20; the clearance of CysC was 17.3+/-6.6 mL/min; and the quantity of CysC removed averaged 2.13 mg/hr. During CVVH (2 L/hr), the quantity of CysC removed is less than 30% of its production and no rapid changes in its serum concentration are observed. Therefore, CVVH (2 L/hr) is unlikely to influence serum concentrations of CysC significantly, which suggests that it can be used to monitor residual renal function during CVVH.

Acute Kidney Injury↗
PubMed2006

Dry body weight: water and sodium removal targets in PD.

BACKGROUND/AIMS: Cardiovascular mortality is high in peritoneal dialysis patients. This may be due to the presence of hypertension and fluid overload. Dietary intake of water and sodium are likely to be important, especially in anuric patients. METHODS: A review of the literature on assessment of fluid status, and on peritoneal removal of water and sodium. RESULTS: MF-BIA added to clinical judgement is helpful for the assessment of fluid status. Natriuretic hormones in patients without heart failure are promising, but their value in clinical practice has not been established yet. Peritoneal ultrafiltration and sodium removal in anuric peritoneal dialysis patients are associated with survival. APD patients have lower sodium removal than CAPD, icodextrin increases it. The value of routine use of low sodium dialysis solutions has not been established. Definite targets on fluid and sodium removal have not been established, but the maintenance of euvalemia, while reducing the exposure to 3.86% glucose solutions at the same time, is largely facilitated by dietary salt and water restrictions. CONCLUSION: MF-BIA is a useful addition to clinical judgement of hydration status. The use of high dose loop diuretics facilitates water and salt removal in the presence of residual renal function. A dietary salt restriction of 4 g/day in anuric patients improves hypertension and is likely to reduce fluid intake.

Body Water↗
PubMed2005

IgG and complement receptor expression in children treated by peritoneal dialysis.

Children treated by peritoneal dialysis (PD) are at increased risk of infections. IgG receptors (FcgammaRs) and complement receptors (CRs) on white blood cells (WBCs) are important for the phagocytic process. We have investigated FcgammaR and CR expression on monocytes, macrophages and neutrophils in blood and in peritoneal dialysis effluent (PDE) of 39 PD children. WBCs were isolated from blood and PDE, labelled with FITC-conjugated CD16 (FcgammaRIII), CD32 (FcgammaRII), CD64 (FcgammaRI), CD11b (CR3) and CD35 (CR1) monoclonal antibodies, and analysed by flow cytometry. Peritoneal cells had lower percentages of FcgammaR-positive or CR-positive cells than blood. On the other hand, the receptor number per cell [mean fluorescence intensity (MFI)] was higher on peritoneal macrophages and neutrophils than blood, except for CD16. The FcgammaR and CR expression in blood and dialysate did not change significantly during the first year of PD treatment. During a peritonitis episode the MFI of all receptors in blood increased only on monocytes, with the exception of CD32. The percentages of FcgammaR-positive and CR-positive macrophages and neutrophils in the PDE increased, whereas the MFI did not increase consistently. Peritoneal cells of PD children showed a lower percentage of FcgammaR-positive and CR-positive neutrophils and macrophages, combined with an increased MFI, indicating a state of activation. Blood and peritoneal cells are capable of up-regulating the receptor expression during peritonitis but probably not to a maximum level.

Adolescent↗
PubMed2005

The Kidney Disease Outcomes Quality Initiative (K/DOQI) Guideline for Bone Metabolism and Disease in CKD: association with mortality in dialysis patients.

BACKGROUND: In 2003, the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (K/DOQI) published a guideline recommending tight control of serum calcium, phosphorus, calcium-phosphorus product (Ca x P), and intact parathyroid hormone levels in patients with chronic kidney disease. Within the context of this guideline, we explored associations of these plasma concentrations with all-cause mortality risk in incident dialysis patients in The Netherlands. METHODS: In a large, prospective, multicenter, cohort study (Netherlands Cooperative Study on the Adequacy of Dialysis), we included 1,629 patients new on hemodialysis or peritoneal dialysis therapy between 1997 and 2004. Multivariate Cox regression models containing calcium level, phosphorus level, intact parathyroid hormone level, age, comorbidity, primary kidney disease, nutritional status, albumin level, dialysis dose, and hemoglobin level were used to examine mortality risks. RESULTS: Mean age was 60 +/- 15 (SD) years, 61% were men, and 64% were treated with hemodialysis. In adjusted time-dependent survival analysis, all-cause mortality risk increased in hemodialysis patients by 40% (hazard ratio [HR], 1.4; 95% confidence interval [CI], 1.1 to 1.7) and in peritoneal dialysis patients by 60% (HR, 1.6; 95% CI, 1.1 to 2.4) for plasma phosphorus levels greater than the target. In addition, having elevated plasma Ca x P product levels increased mortality risk by 40% (HR, 1.4; 95% CI, 1.1 to 1.8) in hemodialysis patients and 50% in peritoneal dialysis patients (HR, 1.5; 95% CI, 1.0 to 2.2). In both patient groups, no significant effects were observed for plasma levels less than the targets. CONCLUSION: In time-dependent survival analysis, the presence of plasma phosphorus and Ca x P product concentrations greater than K/DOQI targets increased all-cause mortality risk in hemodialysis and peritoneal dialysis patients.

Aged↗
PubMed2005

Predictors of survival in anuric peritoneal dialysis patients.

BACKGROUND: Residual glomerular filtration rate (GFR) is a much more important determinant of survival in peritoneal dialysis patients, than peritoneal solute clearances. However, anuric peritoneal dialysis patients are solely dependent on peritoneal solute clearances. The aim of the study was to analyze the effects of peritoneal small solute clearances and ultrafiltration on survival in anuric patients, and to establish the minimum levels of small solute clearances and net ultrafiltration. These objectives were investigated in a prospective cohort study in incident peritoneal dialysis patients who had become anuric during follow-up. METHODS: The Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) is a prospective multicenter cohort study in which new adult dialysis patients are included and followed during 6 months intervals. Included were 542 peritoneal dialysis patients. Of these, 166 developed anuria, 130 of which could be included in the study. RESULTS: Two-year patient survival after the outset of anuria was 67%, technique survival 73%, and the combined 2-year patient and technique survival was 50%. Risk factors associated with mortality were age, comorbidity, the duration of peritoneal dialysis before anuria, and a low serum albumin. Peritoneal solute clearances were analyzed time-dependently. These parameters were not associated with survival when analyzed as continuous variables and also not when the analyses were done in quintiles, although the time-dependent approach was almost significant for Kt/V(urea). On the other hand, when the results were analyzed dichotomously using predefined cutoff points, Kt/V(urea) <1.5 per week and creatinine clearance <40 L/week/1.73 m2 were associated with an increase in the relative risk of death. Also peritoneal ultrafiltration was significantly associated with survival. CONCLUSION: The survival of anuric peritoneal dialysis patients is in line with expectations based on the duration of dialysis. The risk factors for death are the same as in the dialysis population as a whole. Besides an association with ultrafiltration, our study enabled us to define the lower limits of adequate peritoneal dialysis, that is Kt/V(urea) <1.5 per week and creatinine clearance <40 L/week/1.73 m2.

Adult↗
PubMed2005

Incidence of recombinant erythropoietin (EPO) hyporesponse, EPO-associated antibodies, and pure red cell aplasia in dialysis patients.

BACKGROUND: Since 1998, an increase of anti-erythropoietin (anti-EPO) antibody-induced pure red cell aplasia (PRCA) has been reported. As data up to now consisted mostly of spontaneously reported cases the question arose about the frequency of this increase in EPO-induced PRCA. The objectives of this study were to determine the incidence and causes of recombinant EPO hyporesponse, of antibodies to EPO in patients on dialysis, and to relate the detection of anti-EPO antibodies to the presence of PRCA. METHOD: This multicenter cohort study used existing patient data and serum samples collected at 6-month intervals from 1677 patients with incident end-stage renal disease (ESRD) participating in The Netherlands Cooperative Study on the Adequacy of Dialysis-2 (NECOSAD-2). RESULTS: Fifty-seven patients had an inadequate EPO response, which resulted in an incidence of 16.7 per 1000 patient-years on EPO while on dialysis. All available sera specimens (N = 232) of these patients were screened for anti-EPO antibodies. The sera specimens of two of these 57 patients tested positive. Of the 57 patients with inadequate EPO response, one had clinical PRCA (incidence 0.29 per 1000 patient-years on EPO and on dialysis). Of the 1346 patients without symptoms of inadequate EPO response, one patient tested borderline positive for anti-EPO antibodies. In total, three patients developed EPO antibodies during follow-up, leading to an estimated incidence of 1.27/1000 (95% CI 0.3 to 3.7/1000) patient-years since the start of dialysis. CONCLUSION: The incidence of inadequate EPO response in our population of dialysis patients is in concordance with tentative calculations found in the literature. Furthermore, we found the incidence of EPO-induced PRCA and EPO antibodies to be low.

Adult↗
PubMed2005

The contribution of free water transport and small pore transport to the total fluid removal in peritoneal dialysis.

BACKGROUND: Water transport in peritoneal dialysis (PD) patients is across the small pores and water channels, the latter allowing free water transport. The objective of the study was to investigate the contribution of each transport route on transcapillary ultrafiltration (TCUF). METHODS: Standard peritoneal permeability analyses of 80 stable PD patients were analyzed. Twenty-nine patients were followed longitudinally. Fluid transport through small pores (SPT) was assessed by the amount of transported sodium. Free water transport (FWT) was calculated by subtracting SPT from TCUF. The contribution of FWT and SPT to the TCUF and water transport rates at any time point was computed. RESULTS: The ultrafiltered volume due to SPT increased gradually during the dwell, while FWT reached its maximum around 3 hours. The rate of FWT decreased continuously during the dwell. SPT decreased during the initial 2 hours and remained stable thereafter. At 60 minutes, the SPT (P < 0.05) and its contribution (P < 0.05) were positively related to the MTAC(creat). The contribution of FWT after 1 hour, but not the absolute amount, showed an inverse relationship. Peritoneal solute transport parameters (P < 0.01) and the contribution of SPT (P= 0.08), but none of the other fluid parameters showed a U-shape with the lowest values in the second year of PD (P < 0.01). CONCLUSION: The dwell courses of water transport suggest that the activity of water channels is dependent and limited by the crystalloid osmotic pressure gradient, while other determinants are important in SPT. The time-course of SPT paralleled that of peritoneal solute transport parameters.

Adult↗
PubMed2005

ACE I/D polymorphism is associated with mortality in a cohort study of patients starting with dialysis.

BACKGROUND: In dialysis patients, only a few follow-up studies have addressed the relationship between the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene and mortality, but the available data are contradictory. METHODS: A cohort of 453 consecutive patients starting dialysis between January 1999 and January 2002 and participating in a Dutch multicenter prospective study was examined. Patients who died within 3 months after the start of dialysis were excluded. Patients were followed until date of death or censoring in November 2003. RESULTS: The ACE II, ID, and DD genotype frequencies were 24.3% (N = 110), 50.1% (N = 227), and 25.6% (N = 116). Besides a slightly higher number of Caucasians in the DD group, all other patient characteristics of the 3 ACE groups were similar at the start of dialysis. After adjustment for age, comorbidity, and ethnic background, patients with the ID and DD genotype showed an increased hazard ratio (HR) for all-cause mortality of 1.55 (95% CI 1.00-2.42) and 2.30 (95% CI 1.41-3.75), compared to patients with the II genotype. Slightly lower HRs were found for cardiovascular mortality. All groups of primary kidney disease showed a 2- to 3-fold increased adjusted HR for DD. CONCLUSION: The DD genotype identifies dialysis patients at an increased risk for mortality.

Aged↗
PubMed2005

Effects of inhibition of the polyol pathway during chronic peritoneal exposure to a dialysis solution.

BACKGROUND: Peritoneal dialysis with glucose- and lactate-containing dialysis solutions stimulates peritoneal angiogenesis and fibrosis. These serious side effects can also be induced by chronic peritoneal exposure to dialysis solutions in nonuremic rats. The high glucose concentrations of the dialysis solutions may saturate physiological glucose metabolism pathways and stimulate the polyol pathway that has been described to damage nerves and vessels in diabetes mellitus. To investigate the role of the polyol pathway in the development of fibrosis and angiogenesis during chronic peritoneal exposure, the rate-limiting aldose reductase activity in the polyol pathway was inhibited in a chronic peritoneal exposure model in the rat, in which different administration routes were compared. EXPERIMENTAL PROCEDURES: Three groups of rats received daily intraperitoneal infusion with lactate/glucose (3.86%)--containing dialysate via a peritoneal catheter with a subcutaneous puncture device, for 14 weeks: group 1 received only the dialysis solution, groups 2 and 3 received, in addition, zopolrestat, administered either orally (group 2) or intraperitoneally (group 3). After sacrifice, omental tissue was examined by histology for the presence of fibrosis (Picro Sirius Red) and the number of blood vessels (CD31). RESULTS: Histology revealed significantly less Picro Sirius Red-positive tissue in perivascular areas of both experimental groups and submesothelial areas of the oral group in comparison to the control group. There were significantly fewer CD31-positive vessels perfield in both groups treated with zopolrestat compared to the infusion-only group: group 2, 9 (7 - 12); group 3, 17 (13 - 38), compared to group 1, 37 (32 - 39), p < 0.05. CONCLUSION: The combination of peritoneal exposure to dialysis fluids and administration of zopolrestat, a newly developed inhibitor of aldose reductase activity, resulted in less fibrosis and fewer peritoneal vessels than exposure to dialysis fluids only, in a long-term exposure model in the rat. Inhibition of the polyol pathway may thus offer an important contribution to allow long-term continuation of peritoneal dialysis.

Aldehyde Reductase↗
PubMed2005

The difference in causes of early and late ultrafiltration failure in peritoneal dialysis.

OBJECTIVE: Ultrafiltration failure (UFF) is a major complication of peritoneal dialysis. Although it seems associated with long-term treatment, it can also occur in recently started patients. To identify the causes of this complication in patients with early and late UFF we studied a group of 48 patients. Patients were classified as early if they had been treated for less than 2 years and as late if they had been treated for more than 4 years. METHOD: The patients were studied using a standard peritoneal permeability analysis. They all had a net ultrafiltration of less than 400 mL after a 4-hour dwell with 3.86% glucose. As possible causes for UFF, the solute transport parameters dialysate-to-plasma ratio (D/P) and mass transfer area coefficient of creatinine were compared, as well as the effective lymphatic absorption rate (ELAR) and the maximum dip in D/P sodium as an assessment of osmotic conductance to glucose. RESULTS: 25 short-term patients were compared with 23 long-term patients. Both groups showed an equal distribution of high small solute transport rates as a cause of UFF. The chi-square test showed that a high ELAR was a more frequent cause in early UFF compared to late UFF. However, a decreased osmotic conductance to glucose was significantly more often observed in late UFF. Some patients showed more than one cause of the complication. CONCLUSION: This study has shown that UFF in long-term patients is often caused by a decreased osmotic conductance to glucose, most likely caused by a dysfunction of peritoneal water channels in combination with increased peritoneal surface area. In short-term patients, aquaporin dysfunction is rare, but a high ELAR was a very important factor in the occurrence of UFF.

Adult↗
PubMed2005

When to start dialysis treatment: where do we stand?

BACKGROUND: Since the publication of opinion-based guidelines regarding the timing of dialysis treatment, there has been a trend toward earlier initiation. OBJECTIVE: In this review, the existing guidelines and the currently published studies that evaluate them are discussed. RESULTS: These studies could not demonstrate a clear benefit on survival or quality of life for patients who started with relatively higher renal function. CONCLUSION: Early start of dialysis treatment should not be confused with early referral to the nephrologist. It is concluded that initiation of dialysis should not depend on a predefined magnitude of renal function, but should be tailored to the individual patient.

Humans↗