Chronic Hemodialysis Population Research Articles

Clinical Evaluation of a New High Efficiency Hemodialyzer: Polysynthane™

Two increasingly common characteristics of the American chronic hemodialysis (HD) population, high hematocrit and large body size, may render the currently recommended adequacy targets difficult to achieve, even with very efficient dialyzers. In a group of patients with these characteristics, we assessed the ability of a new high efficiency dialyzer (PSN210; Baxter Healthcare Corporation) to achieve the currently recommended adequacy targets. Six patients (mean pre-HD weight and hematocrit, 90.3 +/- 18.0 kg and 0.40 +/- 0.03 kg, respectively) were evaluated. At prescribed blood and dialysate flow rates of 400 and 800 ml/min, respectively, and a mean treatment duration of 4 hrs, mean delivered urea Kt/V and reduction ratio (URR) were 1.38 +/- 0.25 and 0.73 +/- 0.07, respectively. For the same flow rates, whole blood clearances for urea, creatinine, and phosphate were 315 +/- 13, 246 +/- 28, and 260 +/- 27 ml/min, respectively. These data indicate this dialyzer has an efficient mass transfer design allowing adequate dialysis to be delivered even to very large patients under high efficiency conditions.

Hypotransferrinemia of chronically hemodialyzed patients.

Increasingly, the iron needs of hemodialysis patients receiving erythropoietin are being met by infusions of intravenous iron guided by laboratory tests to measure body iron availability. The interpretation of assays based on ferritin and transferrin must take into account the effect of inflammation on both proteins and malnutrition on the latter. In our chronic hemodialysis population, hypotransferrinemia was present in greater than 90% of the patients. Using statistical methods and laboratory studies, we sought to identify the principal reasons for the high prevalence of hypotransferrinemia. We observed that transferrin levels were disproportionately low relative to albumin and prealbumin and correlated inversely with ferritin levels. There was no correlation between transferrin and the soluble transferrin receptor. After the infusion of 900 mg of iron, transferrin saturation increased and total transferrin decreased so that unsaturated iron bonding capacity decreased as well. Ferritin concentrations increased significantly after iron loading. Attempts to demonstrate activation of the patients' antioxidant mechanisms associated with iron infusion were negative. We concluded that the low transferrin may be principally the result of diminished synthesis related to the chronic inflammatory status of hemodialysis patients, which favors production of ferritin, but iron and nutritional status may also influence the blood transferrin concentration. These factors make interpretation of transferrin-dependent assessment of body iron stores unreliable and can result in inadequate or overly aggressive iron-replacement therapy.

Cefazolin in chronic hemodialysis patients: A safe, effective alternative to vancomycin

Vancomycin use is common in hemodialysis patients, due in part to the ease of dosing, but can lead to the development of resistant organisms, including vancomycin-resistant enterococcus. Alternate antibiotics may be equally effective and allow similar dosing in the chronic hemodialysis population. A retrospective review of culture results from a 217-patient, non-hospital-based outpatient hemodialysis center was performed over a 7-month period. Wound and blood culture sensitivity to cefazolin, vancomycin, cefazolin plus gentamicin, and vancomycin plus gentamicin was analyzed. Cefazolin was equivalent to vancomycin for empiric treatment of clinically significant infections in a population with a low rate of methicillin-resistant Staphylococcus aureus infection. Cefazolin plus gentamicin was superior to vancomycin alone. The vancomycin plus gentamicin combination did provide minimally broader coverage than the cefazolin plus gentamicin combination. A prospective pharmacokinetic analysis of postdialysis cefazolin dosing was performed in anuric chronic hemodialysis patients dialyzed with polysulfone dialyzers. Peak, predialysis, and postdialysis cefazolin levels were obtained. Nondialysis clearance of cefazolin was sufficiently low (k(e), 0.027; t(1/2), 26.4 hours) and dialysis clearance sufficiently high (k(e), 0.254; t(1/2), 3.19 hours) to provide for safe and effective peak and trough cefazolin levels with postdialysis dosing in anuric hemodialysis patients. In conclusion, cefazolin alone or with gentamicin in an appropriate empiric antibiotic choice in chronic hemodialysis patients dialyzed in a nonhospital setting with low methicillin-resistant S. aureus infection rates. For infections with documented sensitivity to cefazolin, a 1 g intravenous dose postdialysis (750 mg in patients weighing <50 kg) is safe and effective. (Am J Kidney Dis 1998 Sep;32(3):401-9)

Reassessing the cardiac risk profile in chronic hemodialysis patients: a hypothesis on the role of oxidant stress and other non-traditional cardiac risk factors.

Cardiovascular disease is the single largest cause of mortality in the general population (1) and, as such, it is not surprising that it is also the leading cause of mortality in chronic hemodialysis patients, accounting for nearly half of all deaths in this population in the United States (2). Numerous studies have described the high prevalence of atherosclerotic cardiovascular disease (2,3) and congestive heart failure in the ESRD population (4,5), with these entities accounting for a great majority of cardiovascular mortality in the chronic hemodialysis population.

Intake of vitamins and minerals in stable hemodialysis patients as determined by 9-day food records

Objective: To determine the dietary intake of vitamins, minerals and trace elements in a chronic hemodialysis population. Setting: University-owned chronic hemodialysis center. Patients: Twenty-five patients dialyzed with cellulose acetate or cellulose membranes. The average Kt V was 1.18 ± .12, the mean caloric intake was 1656 ± 538 kcal/d and the mean protein intake was 61.1 ± 17.2 g/d (.86 ± .22 g/kg/ideal body wt). Data source: Nine-day food record histories. Results: The mean daily intake of most water-soluble vitamins was less than the recommended daily allowance (RDA), with the most deficient intakes observed for vitamin B 6 (64% of RDA) and riboflavin (84% of RDA). Only mean vitamin B 12 intake was greater than the RDA. For the fat soluble vitamins the mean intake of both vitamins A and E was less than the RDA (63% and 73%, respectively). Mean iron intake was 101% of the RDA, whereas mean zinc intake was only 60% of the RDA. Intake of folic acid was greater in our patients compared with previous studies in Australian, Danish, and British patients. In addition, intake of thiamine and vitamins B 6 and C was higher, and intake of niacin was lower in our patients compared with Australian patients. Conclusion: There is marked variability in the intake of vitamins and minerals in chronic hemodialysis patients. Careful attention should be paid to regional and national differences in dietary intake of vitamins, trace elements, and minerals in hemodialysis patients.

Obesity in a chronic hemodialysis population

Objective: To estimate the prevalence of obesity in the chronic hemodialysis (CHD) population and determine the effect of obesity on the morbidity and mortality in these patients. Design: Retrospective survey with some prospective elements. Setting: Four free-standing outpatient dialysis units. Patients: Of 296 CHD patients screened, 60 obese CHD patients (≥120% ideal body weight and body mass index ≥28) were identified, including 34 males and 26 females of ages 44 to 84 years. The control group included 60 nonobese CHD patients (90% to 110% ideal body weight and body mass index >19 and <28), including 34 males and 26 females ages 43 to 83 years. Interventions: A noninterventional study; routinely collected demographic, anthropometric, bioelectrical impedance analysis, biochemical, urea kinetic, and clinical data were analyzed. Main outcome measures: Comparison of the existence of comorbidities, hospitalization, and mortality in obese and nonobese CHD patients. Results: Obesity is prevalent in 20% of the CHD population. In obese versus nonobese patients, there was an increased incidence of diabetes mellitus in obese patients (48% v 30%), a higher percentage of patients at increased risk of developing coronary heart disease as determined by lipid profiles (52.9% v 36.7%), an increased hospitalization rate (mean annualized hospital days, 35.52 v 17.6 days per year), and increased death rate (5 v 3 incidents), respectively. Conclusion: Increased morbidity and mortality was observed in the obese CHD patients. Further study is warranted to determine the impact of diet, exercise, and physical training on morbidity and mortality in this group of patients.

Catheter-related sepsis complicating long-term, tunnelled central venous dialysis catheters: Management by guidewire exchange

Standard therapy of catheter-related sepsis of long-term, tunnelled, silicone dialysis catheters is catheter removal, parenteral antibiotics, and catheter replacement in a new venous site after documented clearing of bacteremia. This leads to loss of future venous access sites. Thirteen consecutive cases of dialysis catheter-related sepsis in 10 patients successfully managed by guidewire exchange with preservation of the same central venous access site are reported. Although the most common cause of catheter sepsis in this series was coagulase-negative staphylococcus, guidewire exchange also was successful in cases due to gram-negative rods and yeast. To preserve future venous access sites in the chronic hemodialysis population, long-term, tunnelled dialysis catheter-related sepsis should be managed by a short course of parenteral antibiotics and by changing the catheter over a guidewire using the same venous insertion site.

Persistence of antibodies to hepatitis C virus in a chronic hemodialysis population.

In order to evaluate the persistence of antibodies against hepatitis C virus (HCV) in a chronic hemodialysis population, we studied 151 HBsAg-negative patients. Anti-HCV titers were evaluated every 3 months over 1 year, and the serum alanine aminotransferase/serum aspartate aminotransferase ratio monthly from the start of hemodialysis. The anti-HCV titers (ELISA C100-3) remained stable in 127 patients and fluctuated in 24, without an evident correlation with hepatic function. Using our criteria, we found 85 patients with non-A, non-B hepatitis, 57 of them with biochemical criteria of chronic hepatic disease. There was a strong correlation between antibodies to HCV and non-A, non-B hepatitis (chi 2; p < 0.05) which was more marked in those patients with biochemical criteria of chronic hepatic disease (chi 2; p < 0.001). We concluded that the anti-HCV titer is reliable as a long-term marker of hepatitis C virus infection.

The Impact of Diagnosis-Related Groups on the Cost of Hospitalization for End-Stage Renal Disease Patients at Rhode Island Hospital From 1987 to 1990

The introduction of diagnosis-related groups (DRGs) for the reimbursement of hospital costs in the Medicare population made no provisions to identify end-stage renal disease (ESRD) patients. To assess the impact of the DRGs on ESRD patients, we prospectively evaluated all hospitalizations (901) at the Rhode Island Hospital from July 1987 through April 1990 among a chronic hemodialysis population of 587 patients. The compiled data on length of hospital stay, cost per day, and total cost were compared with the accepted allowances as defined by the DRG codes assigned to the admissions. The mean values and comparisons were length of stay, 10.2 ± 21 days (ESRD) versus 9.7 ± 3.6 days (DRGs), P = 0.44; cost per day, $1,240 ± $685 (ESRD) versus $671 ± $897 (DRGs), P = 0.0001; and total cost, $9,660 ± $17,170 (ESRD) versus $6,815 ± $8,872 (DRGs), P = 0.0001, a difference of $2,275 per admission. The increase in daily, and thus total, costs was primarily due to the use of supplies, medications, laboratory procedures, and transfusion services. It appears from our data that the DRGs do not adequately reflect the cost of caring for ESRD patients with the same DRGs as non-ESRD patients because of increased demand for anCillary services. If these observations are confirmed, a reevaluation of the DRG process as it relates to ESRD patients is warranted.

Development and Use of a Computer-Generated Patient Nutrition Assessment Form

Nutritional assessments collected in the chronic hemodialysis population may include anthropometrics, kinetic modeling, drug-nutrient interactions (DNI), and nutritional diagnostic statements. Intervention and documentation standards exist at state, federal, and network levels. A computer-generated patient nutritional assessment (PNA) form was developed at the authors' outpatient hemodialysis facility to meet these requirements. Necessary data are extracted from a relational data base and a single sheet per patient is printed each month following laboratory data collection week. Pertinent data include the dialysis prescription, diet order, anthropometrics, percentage of ideal body weight, estimate of caloric need, and prescribed medications with known DNI. A 3-month summary of diet-related laboratory data is included. Averaged interdialytic weight changes and dry weight for the corresponding interval also appear. The dietitian formulates nutritional diagnostic statements and chooses a plan of action based on the objective and subjective data. The computer-generated PNA has minimized dietitian data collection time, provided the basis for a comprehensive review of nutritional status, become a readily accessible record for use in patient care plan meetings; it also functions as a quality control tool in meeting state, federal, and network standards of care. The PNA has allowed the dietitian to spend less time with the medical record and more time with patient intervention.

Serum aluminium level in the veneto chronic haemodialysis population: cross-sectional study on 1,026 patients.

A total of 1,026 patients undergoing haemodialysis as the only chronic treatment were studied in all the dialysis units of the Veneto region, Italy. Aluminium was determined in water, dialysis fluids, and patients' serum. Aluminium mean concentration was 9.1 micrograms/l in tap water and 13.3 and 15.7 micrograms/l in bicarbonate and acetate haemodialysis fluids, respectively. Patients' serum aluminium mean level was 52.0 micrograms/l with the following frequency distribution: 59.2% below 60 micrograms/l, 25.5% between 60 and 100 micrograms, and 15.3% above 100 micrograms/l. The mean serum aluminium level was higher in patients undergoing haemodialysis with aluminium concentration in fluids over 10 micrograms/l. This was true also in patients not receiving aluminium hydroxide. Furthermore, we found higher average serum aluminium in those treated with aluminium hydroxide more than 3 g/day. No relationship was found between serum aluminium and sex, age, dialytic age, parathyroid hormone, and vitamin D treatment. Moreover, the patients with serum aluminium above 100 micrograms/l had higher serum alkaline phosphatase and lower mean cell volume values. Thus, in our haemodialysis population aluminium overloading occurred in spite of low concentration in water and fluid, and it was a result more of fluid pollution (over 10 micrograms/l) than aluminium hydroxide ingestion (over 3 g/day).

Hepatitis B surface antigenemia in a chronic hemodialysis program: lack of influence on morbidity and mortality.

One hundred one patients established on chronic hemodialysis on January 1, 1978, were retrospectively evaluated over the ensuing 8-year period to determine the effect of hepatitis B surface antigenemia on morbidity and mortality. Sixty-four patients remained HBsAg-negative after reaching end-stage renal disease; 30 were transiently or persistently HBsAg-positive; seven patients were excluded from study because of insufficient data. The HBsAg-positive and HBsAg-negative patients did not differ with respect to age, sex, race, or etiology of renal disease. There were no differences between the positive and negative groups in terms of death rates (50% v 34.4%, P = not significant), causes of death, hospitalizations (1.5 v 1.2/patient/yr), or hospitalized days (18.0 v 11.8 patient/yr). Only mild liver enzyme elevation (SGOT) was observed at the time of conversion in 13 patients with enzyme abnormalities who seroconverted after beginning hemodialysis (mean SGOT 255 micron/mL). No patient had persistent liver enzyme elevation over the 8-year period. These data suggest that chronic hepatitis B surface antigenemia is not, in itself, associated with increased morbidity or mortality in a chronic hemodialysis population.

Results of Carpal Tunnel Release in Renal Hemodialysis Patients

Forty-eight renal hemodialysis patients were evaluated clinically and electrodiagnostically for carpal tunnel syndrome (CTS). The incidence (32%) was significantly higher than that previously reported by other authors. All patients with CTS also had peripheral neuropathy by electrodiagnostic criteria. CTS was found four times as often in patients who had dialyzed longer than five years compared to those who had dialyzed less than five years. Patients with CTS were more likely to have an active or inactive access in the involved forearm than were patients without CTS. In patients with CTS treated by transverse carpal ligament release, 87.5% obtained relief from pain and numbness. Because of the high incidence of CTS in the chronic hemodialysis population, electrodiagnostic screening is recommended in these patients. Patients with clinical and electrodiagnostic signs of CTS will benefit from transverse carpal ligament release.

Allergy to ethylene oxide in chronic hemodialysis patients.

Almost a decade ago, a single chronic hemodialysis patient in Hamilton, Ontario, Canada, who was experiencing recurrent acute reactions during hemodialysis was found to have become allergic to ethylene oxide gas (EO). This observation recently provided a stimulus to examine the possibility that others exhibiting acute allergic-type reactions during hemodialysis might be similarly sensitized. Serum was obtained from 27 reacting patients and tested in a radioallergosorbent test (RAST) for antibodies to EO. The test was positive for 22 of these sera. EO-related specificity of the antibodies was confirmed. However, EO sensitization was not found in other hemodialysis patients with isolated eosinophilia. In a survey of the current Hamilton chronic hemodialysis population for EO-related antibodies, 9% had a positive allergy skin test and 12% had a positive RAST. The sensitized individuals had no distinctive symptoms. The lesser sensitivity of the skin test contrasts with usual findings in allergic individuals; however, the use of histamine and codeine in chronic hemodialysis and peritoneal dialysis patients might well explain a reduced sensitivity of the EO-related allergy skin test. Chronic peritoneal dialysis could not be invoked as a source of sensitization. None of these patients had a positive skin test or RAST for EO-related antibodies that could be attributed to peritoneal dialysis.

Lymphocytotoxins in a Chronic Hemodialysis Population

Patients in a chronic hemodialysis program were studied over a period of 2½ years to determine whether or not blood transfusions cause the development of cytotoxic antibodies. Blood exposure was moderate in quantity and varied in the type of processing used. No patient was demonstrated to have converted from negative serum cytotoxicity to positive serum cytotoxicity on the basis of blood transfusions given while on dialysis. The use of leukocyte‐free blood, although theoretically desirable, was not shown to be necessary by this study.