The effect of comorbid conditions on hemodialysis access patency

Studying the Effects of Systemic Inflammatory Markers and Drugs on AVF Longevity through a Novel Clinical Intelligent Framework

Although arteriovenous fistula is the preferred vascular access method, it has challenges in three phases of planning, maturation, and maintenance. We looked at the root of fistula challenges in the maintenance phase and found traces of inflammation. Accordingly, we investigated the role of systemic inflammation in this phase to understand its effects on post-maturation function and extract knowledge to help extend fistula longevity. Previous studies on longevity of fistula have focused entirely on statistical tests, and since they put limitations on data, we also used a data mining framework for data analysis. For prediction, we used Decision Tree, Random Forest, and Support Vector Machines, and for inferential analysis, we used Wilcoxon and Chi-squared tests. We analyzed the archived data of 119 hemodialysis patients. In these data, independent variables were serum inflammatory markers, serum metabolic values, anti-inflammatory drugs, and demographic characteristics, and the dependent variable was fistula longevity separated in classes of equal to or greater than four and less than four years. Both predictive and inferential approaches have shown that serum inflammatory markers had no significant involvement in fistula longevity, but some anti-inflammatory drugs were effective. The results have shown that blood tests and drug variables, alone or together, could predict longevity class by 100% accuracy. This prediction can help surgeons make better decisions in selecting patients for fistula creation. Also, the extracted knowledge can provide guidelines for post-maturation disorders.

Conversion of vascular access type among incident hemodialysis patients: description and association with mortality

BACKGROUND

Limited data exist describing vascular access conversions during the first year on dialysis therapy or the effect of converting to and from a catheter on subsequent mortality risk.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We studied a random sample of incident US hemodialysis patients (initiated long-term dialysis < 30 days before study entry) in the Dialysis Outcomes and Practice Patterns Study (DOPPS; 1996-2004).

PREDICTORS

At dialysis therapy initiation, we assessed vascular access type in use (arteriovenous fistula [AVF], arteriovenous graft [AVG], or catheter) and other patient characteristics. We characterized changes in vascular access type (conversions) by using regularly collected functional status information.

OUTCOME & MEASUREMENTS

We assessed time to all-cause mortality. We first described conversions, then used time-dependent Cox regression to estimate mortality hazard ratios (HRs) for conversions from a catheter to a permanent vascular access (versus no conversion) and conversions from a permanent vascular access to a catheter (versus no conversion).

RESULTS

The study included 4,532 patients; 69.2% were dialyzing with a catheter; 17.6%, with an AVG; and 13.1%, with an AVF. In patients initiating therapy with an AVF or AVG, 22% experienced a conversion (failure), and median times to first failure were 62 and 84 days, respectively. In catheter patients, 59% converted to an AVF/AVG (predominantly AVG [57%]); median times to first conversion were 92 and 66 days, respectively. Conversion to a permanent access was associated with an adjusted mortality HR of 0.69 (95% confidence interval, 0.55 to 0.85). The effect was similar for conversion to an AVF or AVG, and these persisted across demographic groups and facilities with different conversion practices. Conversion from a permanent vascular access to a catheter was associated with an adjusted mortality HR of 1.81 (95% confidence interval, 1.22 to 2.68).

LIMITATIONS

Potential for residual confounding because of unmeasured factors influencing decision to convert.

CONCLUSION

Vascular access conversions are common in incident patients. Continued efforts to increase early nephrologist referral and permanent vascular access placement may help decrease mortality risk in incident dialysis patients.

Evaluation of the efficacy of the transposed upper arm arteriovenous fistula: A single institutional review of 190 basilic and cephalic vein transposition procedures

INTRODUCTION

Although autogenous brachial-basilic upper arm transpositions (BVT) have been extensively utilized, there has been significant disparity in published patency rates. Very little is known about the efficacy of autogenous brachial-cephalic upper arm transpositions (CVT). We evaluated our experience with transposed upper arm arteriovenous fistulas (tAVF) in order to assess patency and identify factors that affect efficacy. We then compared our tAVF patients with a cohort of upper arm arteriovenous grafts (AVG).

METHODS

A retrospective review was conducted of tAVF performed at our institution from 1998 to 2004. The tAVF group consisted of 119 BVT and 71 CVT procedures. We compared these with 164 AVG. tAVF were placed only for veins >/=2.5 mm in diameter by duplex ultrasonography.

RESULTS

Mean follow-up was 28 months. With the exception of mean vein diameter, the patients in the BVT and CVT groups had similar demographic parameters and complication rates. Primary and secondary patency rates were 52% and 62% at 5 years for BVT and 40% and 46% at 5 years for CVT, respectively (P = NS). Multivariate analysis revealed that hemodialysis dependence at the time of fistula placement and history of previous upper arm access independently affected primary patency. History of upper torso dialysis catheters independently affected secondary patency. Comparison of the tAVF and AVG groups revealed that tAVF patients were significantly younger, more likely to be male, less likely to be African American (AA) and less likely to have a history of previous AV access. The primary patency rate for tAVF was significantly higher than for AVG: 48% vs 14% at 5 years (P < .001). The secondary patency rate for tAVF was also significantly higher than for AVG: 57% vs 17% at 5 years (P < .001). Among the tAVF procedures, 9% required one or more revisions to maintain secondary patency, compared to 51% with the AVG group (P < .001). Multivariate analysis revealed that presence of AVG and a history of previous upper arm access negatively affected primary and secondary patency.

CONCLUSIONS

Autogenous BVT and CVT have similar, high patency rates. Transposed upper arm arteriovenous fistulas have higher patency rates than upper arm AVG and require significantly fewer revisions. Our data strongly support the contention that as long as the patient is a candidate for an upper arm tAVF, based on anatomical criteria, a tAVF should always be considered before an AVG.

Predictors of delayed transition from central venous catheter use to permanent vascular access among ESRD patients

BACKGROUND

Early arteriovenous fistula (AVF) creation is necessary to curb the use of central venous catheters (CVCs) and reduce their complications. We sought to examine patient characteristics that may influence persistent CVC use 90 days after dialysis therapy initiation among patients using a CVC.

METHODS

Data from the 1999 to 2003 Clinical Performance Measures Project was linked to the Centers for Medicare & Medicaid Services Medical Evidence (2728) form.

RESULTS

Most patients (59.4%) starting dialysis with a CVC failed to transition to permanent access within 90 days, whereas 25.4% received a graft and only 15.2% received an AVF. Older patients (>75 years) were more than 2-fold more likely to remain CVC dependent at 90 days (P = 0.0.001) compared with those younger than 50 years. In addition, race and sex were highly predictive of CVC dependence at 90 days; black females, white females, and black males were 75% (P < 0.001), 61% (P < 0.001), and 35% (P = 0.023) more likely than white males to maintain CVC use, whereas patients with ischemic heart disease and peripheral vascular disease were 35% (P = 0.023) and 39% (P = 0.007) more likely to remain CVC dependent at 90 days, respectively.

CONCLUSION

Prolonged CVC dependence is more likely to occur among patients of older age, females, blacks, and those with cardiovascular comorbidity, suggesting inadequate or late access referral or greater primary access failure. Our findings suggest possible missed opportunities for early conversion of patients to permanent vascular access that may vary by race and sex.

Diabetes and distal access location are associated with higher wall shear rate in feeding artery of PTFE grafts

BACKGROUND

Surgical creation of permanent vascular access for haemodialysis leads to considerable haemodynamic changes. They could be implicated in the pathogenesis of access complications, which limit access survival, especially in diabetics. Physiologically, the relation between arterial diameter and blood velocity is maintained by wall shear stress (WSS), which is directly related to both blood viscosity and wall shear rate (WSR = blood velocity/internal diameter). Because of methodological difficulties, WSR is used as a measure of WSS. Extremely high values of WSS might induce hypercoagulable states, which might contribute to access thrombosis. We performed a study, which was aimed to (i) describe WSR values in feeding arteries of various polytetrafluoroethylene access types and (ii) prove that diabetic patients have higher WSR than non-diabetics.

METHODS

A linear-array 11 MHz probe of SONOS 5500 (Phillips, USA) was used to obtain blood velocity and internal diameter in the feeding arteries of radial or brachial polytetrafluoroethylene grafts. WSR was calculated as 4 x blood velocity/internal diameter. We compared observed values of WSR according to feeding artery (radial vs brachial artery) and according to diabetic status using unpaired t-test.

RESULTS

We included 106 patients (58 non-diabetic and 48 diabetic) in the study. WSR was significantly higher in radial arteries compared with brachial arteries independent of diabetes status. Diabetic subjects had significantly higher WSR in both radial and brachial arteries.

CONCLUSIONS

Diabetes mellitus and distal vascular access creation are associated with higher WSR in the feeding artery. This could be of relevance in the pathogenesis of access complications, e.g. thrombosis, and thus lower patency rates in diabetic patients.

Medical factors affecting patency of arteriovenous access

Arteriovenous access failure is multifactorial in nature with contributions from both medical and surgical etiologies. Medical causes of arteriovenous access failure are rare, and therefore infrequently identified as a major contributing source of malfunction. Although they account for only 10-15% of all cases of access failure, their importance should not be underestimated, especially in cases where a surgical source cannot be identified. Most medical causes are derived from Virchow's triad of endothelial cell injury, stasis, and hypercoaguability. Endothelial cell injury occurs through oxidative stress, activated platelets, increased levels of circulating tumor necrosis factor-alpha, and preexisting intimal hyperplasia. Stasis can occur through prolonged access compression, hypotension, or hypoalbuminemia. Finally, patients with renal failure requiring hemodialysis are frequently at increased risk for hypercoaguable states, except for situations of platelet dysfunction, and therefore access failure. Potential treatments include identifying and removing the offending source, as well as innovative, new medications to prevent their reoccurrence. Treatment is aimed at improving quality of life, as well as decreasing morbidity and hospital admissions in this difficult patient population.

Significance of platelet activation in vascular access survival of haemodialysis patients

BACKGROUND

Vascular access failure is the most common cause of morbidity and hospitalization in haemodialysis (HD) patients. Although there are reports that anti-platelet agents can prevent vascular access thrombosis, the relationship between platelet activation and vascular access failure is not clear. The aim of this study was to investigate the role of platelet activation in recurrent vascular access failure.

METHODS

The studied subjects were divided into three groups: group I included 23 HD patients with recurrent vascular access failure (native arteriovenous fistula <2 year survival or synthetic arteriovenous graft <1 year survival), group II included 15 HD patients with longer vascular access survival (>5 year survival) and group III included 10 healthy volunteers as controls. The expression of platelet activation markers (CD62P and fibrinogen receptor) and the numbers of platelet-derived microparticles were measured and compared between groups.

RESULTS

CD62P-positive platelets were significantly higher in group I than in both group II (7.3+/-3.7 vs 3.5+/-1.3%; P<0.0005) and group III (2.9+/-0.9%; P<0.00005). Fibrinogen receptor-positive (PAC-1-positive) platelets were also significantly higher in group I than in group II (2.2+/-2.1 vs 0.9+/-0.7%; P<0.01) and group III (0.8+/-0.6%; P<0.01).

CONCLUSIONS

A higher level of circulating activated platelets is associated with shorter survival of vascular access in HD patients. The higher level of circulating activated platelets may be a predictor of recurrent vascular access failure. The potential advantageous effects of anti-platelet therapy on this patient population warrant further investigation.

Vascular access and patient outcomes in hemodialysis: questions answered in recent literature

Hemodialysis is not possible without access to the vascular system to provide an adequate and reliable source of blood flow through the hemodialyzer. Since maintenance hemodialysis therapy became a reality in the latter half of the twentieth century, no vascular access has exceeded the success and reliability of arteriovenous fistulae (AVF). They have the lowest infection and thrombosis rates, have the longest patency rates, and are associated with the best morbidity and mortality outcomes of any access modality. In the United States, the majority of patients starting hemodialysis do not have a primary AVF, which may explain why vascular access complications represent almost 20% of the total spending for hemodialysis. In addition, as much as 50% of hospitalization costs for end-stage renal disease are related to access issues. Every effort must be directed in the U.S. as well as elsewhere to promote the use of AVF whenever possible. In some European countries, more than 90% of patients have AVF as their hemodialysis access when nephrologists perform placement of vascular access. Already, some programs in the U.S. have recognized the need for trained nephrologists to provide these services. U.S. interventional nephrologists should be given the opportunity to learn AVF placement procedures to emulate their European counterparts, and thus improve U.S. dialysis outcomes.

Blood flow surveillance of hemodialysis grafts and the dysfunction hypothesis

It is widely recommended that hemodialysis graft surveillance programs should be implemented and that significant stenosis should be corrected when it is accompanied by graft dysfunction. The rationale for surveillance depends on the dysfunction hypothesis, which states that stenosis causes graft dysfunction [such as a decrease in graft blood flow (Qa)], and this dysfunction reliably precedes and accurately predicts thrombosis. The usefulness of Qa surveillance depends on accurate prediction of thrombosis so that stenosis can be corrected prior to thrombosis. An analysis of the dysfunction hypothesis indicates that some or all of its underlying assumptions are invalid. Most importantly, the presence of wide hemodynamic variation during Qa measurements makes Qa a relatively inaccurate predictor of thrombosis. A number of studies have evaluated the value of surveillance with intervention in reducing thrombosis rates and prolonging graft life. Review of these studies show that few have been prospective and randomized, and many have included historical control groups. It is debatable whether these studies have established that Qa surveillance with intervention should be applied to all grafts. Data from several studies suggest that severity of stenosis may be at least as accurate as Qa in predicting thrombosis. Consequently, inclusion of stenosis measurements (e.g., by duplex ultrasound) may improve the results of surveillance. These unresolved issues indicate it is premature to recommend routine Qa surveillance with intervention of all hemodialysis patients with grafts.

The value and limitations of the arm cephalic and basilic vein for arteriovenous access

The National Kidney Foundation has identified the use arteriovenous grafts (AVG) and the interventions required to maintain their patency as two major causes of increased expenditure in the management of hemodialysis access in end-stage renal disease patients. They have issued an appeal for the increased use of native arteriovenous fistulae (AVF). Although the radialcephalic AVF is considered to be the procedure of choice for these patients, other veins should be sought after to maintain an all-autogenous AVF policy. We examined our experience of using arm veins that were transposed to the brachial artery. Over the last 2.5 years, 109 brachiocephalic AVF (BCAVF) and 63 brachiobasilic AVF (BBAVF) were placed in 163 patients with chronic renal failure. In each group, 40 and 25 patients were males, respectively. Ages ranged from 29 to 88 years (mean 67+/-1.4 years) and 37 to 84 years (mean 69+/-2.0 years) in each group. Diabetic patients comprised 56 and 65% of each group and hypertensive patients comprised 73 and 75% of each group. Data collection was via chart review, personal interviews, and review of the dialysis records. Patency was assessed by life-table analysis. The log-rank test was performed in conjunction with Kaplan-Meier survival analysis. Our results showed that the use of BCAVF and BBAVF appears to be a viable alternative to prosthetic arteriovenous grafts. On the basis of our experience, an algorithm for placement of AVF is suggested.

Does blood flow accurately predict thrombosis or failure of hemodialysis synthetic grafts? A meta-analysis

A number of studies have reported that a single low blood flow (Qa) measurement in synthetic hemodialysis grafts predicts thrombosis or failure. In a meta-analysis of these studies, we computed receiver operating characteristic (ROC) curves that evaluated the predictive accuracy of a Qa measurement. The ROC curves plotted sensitivity versus false-positive rate for predicting thrombosis or failure at different Qa thresholds. A perfect predictor has an area under the curve (AUC) of 1.0, whereas a predictor with no discriminative ability has an AUC of 0.5. We identified studies through a literature search and included our own unpublished data. A random-effects model was used to combine the ROC curves from different studies. Of 19 identified studies, 12 were suitable for computing binormal ROC curves (6 predicted thrombosis; 6 predicted failure). The studies measured Qa and then observed outcome during periods of 1.5 to more than 6 months. The combined AUCs from these studies indicate Qa was a relatively poor predictor, with 0.70 +/- 0. 04 (range, 0.61 to 0.84) for thrombosis and 0.76 +/- 0.07 (range, 0. 62 to 0.90) for failure. The wide range of AUCs also shows there was much heterogeneity between studies. We conclude that a single Qa measurement does not appear to have enough accuracy to be a clinically useful predictor of graft thrombosis or failure. Serial Qa measurements and identification of factors that caused heterogeneity between studies may be needed to achieve sufficient accuracy.

Hemodialysis access: influence of the human immunodeficiency virus on patency and infection rates

PURPOSE

The complication rate for patients who are dialysis dependent and infected with the human immunodeficiency virus (HIV) and the role of viral indicators (CD4 counts) as predictors of these complications are poorly characterized. To determine the influence of HIV status and viral activity on graft patency and infection rates, we retrospectively reviewed our results.

METHODS

Between June 1993 and March 1997, the charts of 104 patients (HIV+, n = 42; HIV-, n = 62) who required 112 hemodialysis access grafts were reviewed. Of the 112 procedures, 55 (48%) were autologous arteriovenous fistulae (AVF) procedures (HIV+, n = 23; HIV-, n = 32) and 57 (52%) were prosthetic expanded polytetrafluoroethylene grafting procedures (HIV+, n = 27; HIV-, n = 30). Transcutaneous catheter procedures were excluded from the study. The autologous AVF procedures consisted of direct and transposed AVFs. Patency rates were determined by means of life-table analysis. Infection rates and CD4 counts were compared with the chi2 test and the Fisher exact test. Significance was accepted at a P value of.05 or less.

RESULTS

The cumulative 12-month and 24-month patency rates for prosthetic grafts in patients who were HIV+ were 49% and 21%, respectively, versus 77% and 45% for patients who were HIV-. The differences in the prosthetic graft patency rates between these two groups were significant (P </=.05). The cumulative 12-month and 24-month patency rates for autologous AVF procedures did not differ significantly. The AVF procedure patency rates were 72% and 51%, respectively, in patients who were HIV+ versus 54% and 50% for patients who were HIV-. The prosthetic graft infection rate for patients who were HIV+ and HIV- were 30% and 7%, respectively ( P =.04). However, the infection rates in autologous AVF procedures did not differ between the groups (9% vs 0%; P>.05). The mean CD4+ cell counts were 174: CD4+ counts that were less than 200 did not correlate with or predict the development of infection (P >.05).

CONCLUSION

Our data showed that prosthetic graft infection rates were increased and patency rates were decreased in patients who were HIV+ as compared with patients who were HIV- and HIV+ with autologous AVFs. There were no differences in patency rates or infection rates in patients who had undergone autologous access procedures. Long-term graft patency rates were not affected by HIV status, and CD4+ lymphocyte counts were not predictive of infection development. Because the prosthetic graft infection rates exceeded those rates of autologous access procedures, we recommend the vigorous use of autologous AVFs in all patients who are HIV+, regardless of CD4+ count.

A three-year follow-up on standard versus thin wall ePTFE grafts for hemodialysis

PURPOSE

Expanded polytetraflouroethylene (ePTFE) grafts are the most popular prosthetic grafts for hemodialysis patients in whom autogenous fistulas cannot be constructed. Long-term studies to study the durability and complication rate of the different wall configurations of ePTFE grafts have not been carried out. The primary, secondary, and cumulative patency and other complications between standard thickness (STD) and thin wall (THN) 6 mm stretch ePTFE grafts (WL Gore & Assoc, Flagstaff, AZ) was prospectively evaluated.

METHODS

From September 1993 to August 1995, 108 patients receiving new grafts were randomized into 2 groups: those receiving STD grafts (n = 56) or those receiving THN (n = 52) grafts. Data prospectively collected included day of first access, primary patency, interventions required, and long-term results. Infections, pseudoaneurysms, and mortality were also documented. Student's unpaired t-test was used to compare the 2 groups, and log-rank life tables were constructed and compared.

RESULTS

Mean follow-up examination time was 38.1 +/- 0.8 months for STD grafts and 35.1 +/- 1.0 months for THN grafts (P<.03). Longer patency was noted in the STD group of grafts (18.2 months for STD vs. 12.1 months for THN). Biographical data and complications, including pseudoaneurysm (6% vs. 5%), infection (2% vs. 3%), and mortality (22% vs. 19%), between STD and THN groups were not different statistically. Mean primary (18.2 months vs. 12.1 months), secondary (20.9 months vs. 13.7 months), and cumulative patency times (22.2 months vs. 15.2 months) for the STD group were significantly more than those for the THN group (P<.000 by log rank of life tables). Other complications were not different between groups.

CONCLUSION

Standard thickness ePTFE is the graft of choice when placing ePTFE arteriovenous grafts for hemodialysis.

Leukocyte-polytetrafluoroethylene interaction enhances proliferation of vascular smooth muscle cells via tumor necrosis factor-alpha secretion

Intimal hyperplasia of vascular smooth muscle cells (VSMC) at the venous anastomosis of arteriovenous grafts represents the most common cause of vascular access failure in hemodialysis patients. Upstream release of growth factors from leukocytes activated by adhesion to the graft material may play a role in this lesion. We evaluated the effect of interaction of peripheral blood mononuclear cells (PBMC) with polytetrafluoroethylene (PTFE) on proliferation of VSMC. Vascular smooth muscle cell proliferation was significantly increased by conditioned media from human PBMC incubated with PTFE. Peripheral blood mononuclear cell adhesion to PTFE could not be antagonized by the beta 1 integrin ligand-containing peptide GRGDSP, but was attenuated by EDTA consistent with beta 2 integrin-mediated adhesion. Soluble scavenger receptor ligands at high concentrations had no effect on adhesion to PTFE excluding any contributory role of scavenger receptors in this interaction. Neutralizing antibodies to TNF-alpha significantly attenuated the mitogenic effect of PBMC/PTFE conditioned media and a marked increase in TNF-alpha secretion by PBMC on PTFE was detected by ELISA. These studies demonstrate that PBMC interaction with PTFE can promote proliferation of VSMC via increased production of TNF-alpha and perhaps other cytokines. Leukocyte interaction with PTFE causing enhanced secretion of TNF-alpha and consequent VSMC proliferation may account for the development of venous intimal hyperplasia in hemodialysis patients with arteriovenous grafts.

Prospective randomized trial of a metallic intravascular stent in hemodialysis graft maintenance

PURPOSE

To evaluate percutaneous transluminal angioplasty (PTA) alone versus PTA and flexible self-expanding stent placement for the management of hemodialysis access graft stenoses.

MATERIALS AND METHODS

Thirty-seven grafts in 34 patients were evaluated for abnormal intradialytic parameters (n = 27) or occlusion (n = 10). Angiography identified stenoses (mean, 69%; range, 50%-95%) at or within 3 cm of the vein-graft junction (70%) or in the peripheral outflow vein (30%) that had recurred within a 6-month period after previous PTA. They were randomized to PTA alone (n = 20) or PTA with Wallstent (n = 17). Additional lesions were treated by PTA alone, and a mean of 1.4 (range, 1-3) lesions were treated per patient. Significant differences existed in the mean number of previous accesses (1.8 and 0.8 in the PTA and stent groups, respectively) and in the mean number of previous interventions in the current access (1.8 and 2.9, respectively). End points were subsequent radiologic or surgical intervention, transplantation, and death.

RESULTS

Technical success was 100% (mean residual stenosis, 12%; range, 0%-30%). The primary patency of 128 days and secondary patency of 431 days were similar for both groups. Secondary patency required a mean of 1.8 and 1.6 additional interventions for the PTA and stent groups, respectively. The adjunctive stent placement increased the cost of the procedure by 90%.

CONCLUSION

Despite significant added costs, there was no advantage to stent placement for recurrent peripheral hemodialysis graft stenoses that were already adequately dilated with balloon angioplasty.

Determinants of albumin concentration in hemodialysis patients

Hypoalbuminemia predicts mortality in hemodialysis patients with end-stage renal disease and is assumed to result from malnutrition. To investigate a possible alternative cause, we evaluated the relationships between serum albumin (Salb) and serum levels of two positive acute-phase proteins: C-reactive protein (CRP) and serum amyloid A (SAA). We also examined the relationship between Salb and dialysis dose delivered (Kt/V) and normalized protein catabolic rate (PCRn) measured during 3 consecutive months in a group of 115 patients. Serum albumin was measured monthly for 5 months. SAA levels were not increased in the majority of patients, despite its low molecular weight (8 kd), and predialysis concentrations were independent of residual renal function, compatible with a nonrenal site of metabolism. Both CRP and SAA levels correlated negatively with Salb both by linear regression and by multiple regression analysis (P < 0.001). CRP correlated with fibrinogen (P < 0.005). Salb also correlated positively with PCRn (P = 0.001), but not with Kt/V. The Kt/V did not correlate with PCRn. While CRP and SAA correlated with one another, neither variable correlated with PCRn. When either SAA or CRP was high, Salb was low regardless of PCRn. Thus, there are two separate independent factors predicting Salb--markers of inflammation and protein intake--but high concentrations of acute-phase proteins have a greater impact on Salb than does low PCRn. Activity of the acute-phase response is an important predictor of low Salb in hemodialysis patients independently of nutritional factors.