Canadian Hemodialysis Morbidity Study

Self-care of well adult Canadians and adult Canadians with end stage renal disease

Empirical support for Orem's Self-Care Deficit Theory of Nursing [Orem, D.E., 1995. Nursing: Concepts of practice, 5th. ed. Mosby, Toronto] is accumulating. However, little is known about the relative usefulness of the theory with well and chronically ill adults. This research examined multiple relationships deduced from Orem's Theory in 109 well adults and 141 adults with end stage renal disease (ESRD). Relations among personality traits, gender, age, socioeconomic status, self-care agency, and self-care were examined. Qualitative and quantitative differences were evident for the two samples. For example, self-care agency was a stronger predictor of self-care in well adults. Implications for development of disease-specific, mid-range theory are explored.

[Children with chronic renal failure: evaluation of the nutritional status and management]

Since malnutrition is a well recognized problem in children with chronic renal failure, nutritional management of these children is essential. This review describes methods for nutritional assessment and suggests guidelines for providing maximal dietary support in children with chronic renal insufficiency. Optimal nutritional management includes an adequate caloric and protein intake, a restriction of phosphorus intake and an appropriate intake of electrolytes and vitamins.

Dialysis in The Netherlands: the clinical condition of new patients put into a European perspective. NECOSAD Study Group. Netherlands Cooperative Study on the Adequacy of Dialysis phase 1

BACKGROUND

The unadjusted annual mortality rate among prevalent Dutch dialysis patients increased from 1981 to 1992. Part of this increase may be attributed to the ageing of the dialysis population, but hardly any data were available on other important prognostic features of new Dutch dialysis patients, such as co-morbidity and other aspects of their clinical condition. The aim of the present study was to obtain these data and to put them into a European perspective.

METHODS

Two hundred and fifty consecutive new patients were included in this prospective multi-centre study. Data were collected 3 months after start of dialysis. Multivariate linear regression analysis was used to explain the variability of parameters of nutritional state and blood pressure.

RESULTS

Mean age was 57 years, co-morbid conditions were present in 51%, diabetes mellitus in 18%, and cardiovascular disease in 28%. Decreased protein intake was related to diminished residual renal function. Our patients did not have more co-morbidity than Dutch patients participating in a European study some years earlier. Comparison with other studies was complicated by the use of different definitions of co-morbidity and of selected patient populations.

CONCLUSIONS

Despite the fact that Dutch dialysis patients have become older and the incidence of diabetic nephropathy has increased, no conclusions could be drawn on a concomitant increase in co-morbidity. This patient group may serve as a reference population to study future changes in patient case-mix within the Netherlands. Furthermore, the use of common international definitions of co-morbidity is needed to be able to make comparisons of survival data.

Deaths within 90 days from starting renal replacement therapy in the ERA-EDTA Registry between 1990 and 1992

BACKGROUND

Patients who die within 90 days of commencing renal replacement therapy (RRT) may be recorded by some centres and not others, and hence data on mortality and survival may not be comparable. However, it is essential to compare like with like when analysing differences between modalities, centres and registries. It was decided, therefore, to look at the incidence of deaths within 90 days in the ERA-EDTA Registry, and to try to define the characteristics of this group of patients.

METHODS

Between 1 January 1990 and 31 December 1992, 78 534 new patients started RRT in 28 countries affiliated to the ERA-EDTA Registry. Their mean age was 54 years and 31% were over 65 years old. Eighty-two per cent of the patients received haemodialysis (HD), 16% peritoneal dialysis (PD) and 2% had preemptive transplantation as first mode of treatment.

RESULTS

From January 1990 to March 1993 the overall incidence of deaths was 19% and 4% of all patients died within 90 days from the start of RRT. Among those dying within 90 days 59% were over 65 years compared to 53% over 65 years in those dying beyond this time (P<0.0001). The modality of RRT did not influence the distribution of deaths before and after 90 days. Vascular causes and malignancy were more common in those dying after 90 days, while there were more cardiac and social causes among the early deaths. Mortality from social causes was twice as common in the elderly, who had a significantly higher chance of dying from social causes within 90 days compared to those aged under 65 years. The overall incidence of deaths within 90 days was 3.9% but there was a wide variation between countries, from 1.8% to 11.4%. Finally, patient survival at 2 years was markedly influenced in different age groups when deaths within 90 days were taken into account.

CONCLUSIONS

The incidence of deaths within 90 days from the start of RRT was 3.9%, with a marked variation between countries ranging from 1.8% to 11.4%, which probably reflects mainly differences in reporting these deaths, although variable selection criteria for RRT may contribute. Deaths within 90 days were significantly more frequent in elderly patients with more early deaths resulting from cardiac and social causes, while vascular causes of death and malignancy were more common in those dying after 90 days. Patient survival analyses should take into account deaths within 90 days from the start of RRT, particularly when comparing results between modalities, countries and registries.

Body weight-for-height relationships predict mortality in maintenance hemodialysis patients

BACKGROUND

Protein-energy malnutrition is a strong predictor of mortality in maintenance hemodialysis (MHD) patients. This association has generally been described for serum chemistry measures of protein-energy malnutrition. We hypothesized that body weight-for-height relationships also predict survival in MHD patients.

METHODS

During the last three months of 1993, data were obtained on 12,965 men and women concerning clinical characteristics (height, postdialysis weight, age, gender, race, and presence or absence of diabetes mellitus) and laboratory measurements (predialysis serum albumin, creatinine and cholesterol, and the urea reduction ratio). Patient survival during the next 12 months was evaluated retrospectively.

RESULTS

In comparison to values for normal Americans determined from the National Health and Nutrition Evaluation Survey II data, weight-for-height relationships tended to be slightly lower than normal in African American men and women and Caucasian men undergoing MHD and were normal or slightly greater in the taller Caucasian women. In both men and women, the mortality rate decreased progressively as the patients' weight-for-height increased. MHD patients who weighed more than normal had the lowest mortality rates. After adjustment for clinical characteristics and laboratory measurements, the inverse relationship between mortality rates and weight-for-height percentiles was still highly significant for patients within the lower 50th percentile of body weight-for-height. Serum albumin correlated directly with weight-for-height in patients in the lower 50th percentile of weight-for-height. Serum creatinine and cholesterol correlated directly with weight-for-height in the entire population of men and women. In contrast, the urea reduction ratio was inversely correlated with weight-for-height.

CONCLUSIONS

These data indicate that weight-for-height is a strong predictor of 12-month mortality in male and female MHD patients. Multivariate analyses indicate that body weight-for-height is an independent predictor of higher mortality in those patients who are in the lower 50th percentile for this measurement.

Blood pressure variability as an adverse prognostic risk factor in end-stage renal disease

BACKGROUND

Prospective and case-control studies show that blood-pressure variability is an independent risk factor for severe organ damage and cardiovascular events in hypertensives. We prospectively studied the association between systolic blood pressure variability and cardiovascular mortality and mortality from all causes in end-stage renal disease patients.

METHODS AND RESULTS

The subjects were 144 patients (86 men, 58 women; mean age+/-SD, 52+/-13 years) who underwent dialysis in the same dialysis centre and were examined for blood-pressure variability. The study period was 38 months beginning in January 1995, during which six cardiovascular and seven noncardiovascular fatalities occurred. Coefficient of variation in systolic blood pressure in 1994, as an indicator of systolic blood pressure variability, ranged from 7.8 to 14.6%. Cumulative incidence of death from all causes was related to coefficient of variation in systolic blood pressure. The difference between the maximum and minimum systolic blood pressure (deltaSBP) in 1994 ranged from 44 to 146 mmHg (mean+/-SD, 78+/-13 mmHg) and correlated significantly with coefficient of variation in systolic blood pressure (r = 0.65, P<0.0001). Cox regression analysis was used to identify the independent predictors for mortality. The hazard ratio for death from all causes increased 1.63 times per 1% increase in coefficient of variation in systolic blood pressure (hazard ratio; 95% confidence interval: 1.63; 1.05-2.53) and 1.03 times per 1 mmHg increase in deltaSBP (1.08; 1.03-1.14).

CONCLUSION

These results suggest that systolic blood pressure variability may be a significant prognostic factor in end-stage renal disease.

Prevalence of and factors associated with suboptimal care before initiation of dialysis in the United States

Despite improvements in dialysis care, the mortality of patients with end-stage renal disease (ESRD) in the United States remains high. Factors that thus far have received scant attention, but could significantly affect morbidity and mortality in dialysis patients, are the timing and quality of care before the initiation of dialysis (pre-ESRD). Data from the new version of the Health Care Financing Administration (HCFA) 2728 Form were used to examine the prevalence of and factors associated with hypoalbuminemia, severe anemia, and erythropoietin (EPO) use among 155,076 incident chronic dialysis patients in the United States between April 1, 1995 and June 30, 1997. At initiation of dialysis, the median serum albumin and hematocrit were 3.3 g/dl and 28%, respectively. Sixty percent of patients had a serum albumin below the lower limit of normal and 51% had a hematocrit <28%. Overall, only 23% had received EPO pre-ESRD. Among patients with hematocrit <28%, only 20% were receiving EPO, compared to 27% among patients with hematocrit > or =28%. In a multivariate analysis that adjusted for diabetes, functional status, and demographic, socioeconomic, and geographic factors, the odds ratios for hypoalbuminemia, hematocrit <28%, and lack of EPO use were higher for African-Americans, patients with non-private insurance or no insurance, and patients who were started on hemodialysis. There were also significant differences in odds ratios for these outcomes between different geographic regions in the United States. The high prevalence of pre-ESRD hypoalbuminemia, hematocrit <28%, and lack of EPO use suggests that the quality of pre-ESRD care in the United States is suboptimal. Improvement in pre-ESRD care could potentially improve outcomes among ESRD patients.

Predictors of adequacy of arteriovenous fistulas in hemodialysis patients

BACKGROUND

Dialysis access procedures and complications represent a major cause of morbidity, hospitalization, and cost for chronic dialysis patients. To improve the outcomes of hemodialysis access procedures, recent clinical guidelines have encouraged attempts to place an arteriovenous (A-V) fistula, rather than an A-V graft, whenever possible in hemodialysis patients. There is little information, however, about the success rate of following such an aggressive strategy in the prevalent dialysis population.

METHODS

We evaluated the adequacy of all A-V fistulas placed in University of Alabama at Birmingham dialysis patients during a two-year period. A fistula was considered adequate if it supported a blood flow of >/=350 ml/min on at least six dialysis sessions in one month. Fistula adequacy was correlated with clinical and demographic factors.

RESULTS

The adequacy could be determined for 101 fistulas; only 47 fistulas (46.5%) developed sufficiently to be used for dialysis. The adequacy rate was lower in older (age >/= 65) versus younger (age < 65) patients (30.0 vs. 53.5%, P = 0.03). It was also marginally lower in diabetics versus nondiabetics (35.0 vs. 54.1%, P = 0.061) and in overweight (BMI >/= 27 kg/m2) versus nonoverweight patients (34.5 vs. 55.2%, P = 0.07). The adequacy rate was not affected by patient race, smoking status, surgeon, serum albumin, or serum parathyroid hormone. The adequacy rate was substantially lower for forearm versus upper arm fistulas (34.0 vs. 58.9%, P = 0.012). The adequacy of forearm fistulas was particularly poor in women (7%), patients age 65 or older (12%), and diabetics (21%). In contrast, upper arm fistulas were adequate in 56% of women, 54% of older patients, and 48% of diabetics.

CONCLUSIONS

An aggressive approach to the placement of fistulas in dialysis patients results in a less than 50% early adequacy rate, which is considerably lower than that reported in the past. Moreover, the success rate of fistulas is even lower for certain patient subsets. To achieve an optimal outcome with A-V fistulas, we recommend that they be constructed preferentially in the upper arm in female, diabetic, and older hemodialysis patients.

Association of morbidity with markers of nutrition and inflammation in chronic hemodialysis patients: a prospective study

BACKGROUND

Numerous studies suggest a strong association between nutrition and clinical outcome in chronic hemodialysis (CHD) patients. Nevertheless, the pathophysiological link between malnutrition and morbidity remains to be clarified. In addition, recent evidence suggests that nutritional indices may reflect an inflammatory response, as well as protein-calorie malnutrition. In this study, we prospectively assessed the relative importance of markers of nutritional status and inflammatory response as determinants of hospitalization in CHD patients.

METHODS

The study consisted of serial measurements of concentrations of serum albumin, creatinine, transferrin, prealbumin, C-reactive protein (CRP), and reactance values by bio-electrical impedance analysis (BIA) as an indirect measure of lean body mass every 3 months over a period of 15 months in 73 CHD patients. Outcome was determined by hospitalizations over the subsequent three months following each collection of data.

RESULTS

Patients who required hospitalization in the three months following each of the measurement sets had significantly different values for all parameters than patients who were not hospitalized. Thus, serum albumin (3.93 +/- 0.39 vs. 3.74 +/- 0.39 g/dl), serum creatinine (11.0 +/- 3.7 vs. 9.1 +/- 3.5 mg/dl), serum transferrin (181 +/- 35 vs. 170 +/- 34 mg/dl), serum prealbumin (33.6 +/- 9.2 vs. 30.0 +/- 10.1 mg/dl), and reactance (50.4 +/- 15.6 vs. 43.0 +/- 13.0 ohms) were higher for patients not hospitalized, whereas CRP (0.78 +/- 0.89 vs. 2.25 +/- 2.72 mg/dl) was lower in patients who were not hospitalized. All differences were statistically significant (P < 0.05 for all parameters). When multivariate analysis was performed, serum CRP and reactance values were the only statistically significant predictors of hospitalization (P < 0.05 for both). When a serum CRP concentration of 0.12 mg/dl was considered as a reference range (relative risk 1.0), the relative risk for hospitalization was 7% higher (relative risk = 1.07) for a CRP concentration of 0.92 mg/dl and was 30% (relative risk = 1.30) higher for a CRP concentration of 3.4 mg/dl. When a reactance value of 70 ohms was considered as a reference range with a relative risk of 1.0, the relative risk of hospitalization increased to 1.09 for a reactance value of 43 ohms and further increased to 1.14 for a reactance value of 31 ohms.

CONCLUSIONS

The results of this study strongly indicate that both nutritional status and inflammatory response are independent predictors of hospitalization in CHD patients. CRP and reactance values by BIA are reliable indicators of hospitalization. Visceral proteins such as serum albumin, prealbumin, and transferrin are influenced by inflammation when predicting hospitalization. When short-term clinical outcomes such as hospitalizations are considered, markers of both inflammation and nutrition should be evaluated.

Septicemia in dialysis patients: incidence, risk factors, and prognosis

BACKGROUND

Infection is second to cardiovascular disease as a cause of death in patients with end-stage renal disease (ESRD), and septicemia causes a majority of these infectious deaths. To identify patients at high risk and to characterize modifiable risk factors for septicemia, we examined the incidence, risk factors, and prognosis for septicemia in a large, representative group of U.S. dialysis patients.

METHODS

We conducted a longitudinal cohort study of incident ESRD patients in the case-mix study of the U.S. Renal Data System with seven years of follow-up from hospitalization and death records. Poisson regression was used to examine independent risk factors for hospital-managed septicemia. Cox proportional hazards analysis was used to assess the independent effect of septicemia on all-cause mortality and on death from septicemia. Separate analyses were performed for patients on peritoneal dialysis (PD) and hemodialysis (HD).

RESULTS

Over seven years of follow-up, 11.7% of 4005 HD patients and 9.4% of 913 PD patients had at least one episode of septicemia. Older age and diabetes were independent risk factors for septicemia in all patients. Among HD patients, low serum albumin, temporary vascular access, and dialyzer reuse were also associated with increased risk. Among PD patients, white race and having no health insurance at dialysis initiation were also risk factors. Patients with septicemia had twice the risk of death from any cause and a fivefold to ninefold increased risk of death from septicemia.

CONCLUSIONS

Septicemia, which carries a marked increased risk of death, occurs frequently in patients on PD as well as HD. Early referral to a nephrologist, improving nutrition, and avoiding temporary vascular access may decrease the incidence of septicemia. Further study of how race, insurance status, and dialyzer reuse can contribute to the risk of septicemia among ESRD patients is indicated.

Effect of increasing serum albumin on plasma D-dimer, von Willebrand factor, and platelet aggregation in CAPD patients

This study was performed to investigate the interrelation between blood albumin level and D-dimer (a marker of intravascular coagulation) and von Willebrand factor (vWF; a marker of endothelial injury) levels or platelet aggregation. Blood levels of albumin, D-dimer, vWF, and C-reactive protein (CRP) and the threshold aggregating concentration (TAC) of ristocetin were measured in 64 continuous ambulatory peritoneal dialysis (CAPD) patients and compared with 36 healthy controls. Twenty-two CAPD patients with albumin levels less than 3.0 g/dL were divided into experimental and disease-control groups. In the experimental group, levels were measured before and after repeated infusions of 20% albumin, 100 mL/d for 7 days. The same parameters were measured in the disease-control group that did not receive the albumin infusion. CAPD patients had higher D-dimer and vWF levels than the healthy controls. There were inverse correlations between albumin and D-dimer (r = -0.48; P < 0.001), vWF (r = -0.29; P < 0.05), or logCRP (r = -0.44; P < 0.001) in CAPD patients. There were positive correlations between logCRP and D-dimer (r = 0.38; P < 0.01) and between logCRP and vWF (r = 0.32; P = 0.01) in CAPD patients. No change was seen in D-dimer, vWF, and CRP levels in either group. The TAC of ristocetin in the 18 CAPD patients was not different from that in the 11 healthy controls (0.55 +/- 0.09 v 0.65 +/- 0.07 mg/mL). There was a correlation between albumin level and TAC in the CAPD patients (r = 0.59; P < 0.01). TAC increased from 0.50 +/- 0.09 to 0.62 +/- 0.13 mg/mL (123% +/- 17%; P < 0.05; n = 6) at the end of the repeated albumin infusions in the experimental group, whereas it did not change in the control group. CRP level did not change in either group. The results of this study indicate that hypoalbuminemia increases platelet aggregability. The observation that the albumin infusion was not associated with changes in D-dimer and vWF despite the inverse correlations suggests that these relationships may be secondary to other factors, such as inflammation.

Can renal replacement be deferred by a supplemented very low protein diet?

Patients with chronic renal failure are commonly started on renal replacement therapy (RRT) as soon as (or, in some centers, before) the usual criteria for severity are met, i.e., GFR <10 ml/min for nondiabetic patients and <15 ml/min for diabetic patients. To determine whether RRT can safely be deferred beyond this point, adults with all types of chronic renal failure who met these criteria on presentation (23 patients) or who reached these levels of severity during treatment (53 patients) were managed conservatively until RRT was judged necessary by their chosen dialysis or transplantation team, without input into this decision from the present authors. Patients were prescribed a very low protein diet (0.3 g/kg) plus supplemental essential amino acids and/or ketoacids and followed closely. The intervals between the time at which GFR became less than 10 ml/min (15 ml/min in diabetic patients) and the date at which renal replacement therapy was started were used as estimates of renal survival on nutritional therapy. Kaplan-Meier analysis showed median renal survival of 353 d. Acidosis and hypercholesterolemia were both predictive of shorter renal survival. Signs of malnutrition did not develop. Final GFR averaged 5.6 +/- 1.9 ml/min. Two patients died; thus, annual mortality was only 2.5%. Hospitalizations totaled 19 in 93 patient-years of treatment, or 0.2 per year. Thus, these well motivated patients with GFR <10 ml/min (<15 ml/min in diabetic patients) were safely managed by diet and close follow-up for a median of nearly 1 yr without dialysis. It is concluded that further study of this approach is indicated.

Hyperhomocysteinemia, anticardiolipin antibody status, and risk for vascular access thrombosis in hemodialysis patients

BACKGROUND

Vascular access failure is an important cause of morbidity in end-stage renal failure patients on hemodialysis. Currently, little is known about risk factors that predispose certain hemodialysis patients to recurrent access thrombosis. Hyperhomocysteinemia (common in patients with renal failure) predisposes people with normal renal function to recurrent and early-onset venous thrombosis, although the effect on vascular access thrombosis is currently unknown. Previous studies have suggested that high titers of IgG anticardiolipin antibody (IgG-ACA) predispose hemodialysis patients to access thrombosis. This cross sectional study was designed to assess for an association between two predictive variables, hyperhomocysteinemia and elevated titers of IgG-ACA, and vascular access thrombosis in patients undergoing chronic hemodialysis.

METHODS

Risk factors for vascular access thrombosis were documented, and the number of episodes of access thrombosis was recorded for the previous three years in patients undergoing hemodialysis. Midweek predialysis total homocysteine and IgG-ACA levels were measured in all subjects.

RESULTS

Of the 118 patients who were enrolled, 75.4% had a native arteriovenous fistula. Episodes of vascular access thrombosis were recorded for the previous three years; 34 (28.8%, 95% CI 20.9 to 37.9%) patients had 72 episodes of access thrombosis over the period of risk. Mean homocysteine levels were not significantly different between these 34 patients (28.6 micromol/liter, 95% CI 24.5 to 32.7) and the patients who had no episodes of graft thrombosis (29.8 micromol/liter, 95% CI 26.7 to 32.9). Sixty-seven unselected patients had IgG-ACA levels drawn for analysis, and all assays were negative. The only variable that was associated with a higher risk for graft thrombosis was the type of vascular access placed (odds ratio 4.0, 95% CI 1.6 to 9.6 for patients with a synthetic graft compared with those with an arteriovenous fistula).

CONCLUSIONS

No association was found between homocysteine levels or anticardiolipin antibody and vascular access thrombosis in our patient population.

Implementation of the Dialysis Outcomes Quality Initiative Vascular Access Guidelines

To better care for patients with chronic renal failure and end-stage renal disease, the National Kidney Foundation has published a set of Clinical Guidelines, the Dialysis Outcomes Quality Initiative, based on current available evidence and, where such evidence is lacking, the expert opinions of current leaders in vascular access research. These Guidelines were developed to standardize the care of chronic renal failure and end-stage renal disease patients. This report describes some of the more important aspects of these recommendations and the authors' implementation strategies.

Modality-specific nutrition support in ESRD: weighing the evidence

Protein-calorie malnutrition affects a large fraction of patients with end-stage renal disease (ESRD) and contributes significantly to the high rates of mortality and morbidity observed in this population. Observational studies of specific interventions, including intradialytic parenteral nutrition (IDPN), suggest that aggressive nutrition support may be of some benefit to some patients with ESRD. Due in part to lack of data derived from prospective, randomized clinical trials, and to the large expense associated with these therapies, Medicare and other payers have strongly discouraged the prescription of IDPN and other intermittent, dialysis-specific methods of nutrition support, such as intraperitoneal nutrition (IPN). The "burden of proof" has been placed on the dialysis community. In response, we must continue to emphasize the importance of securing nutritional health for all patients on or anticipating renal replacement therapy. Intradialytic parenteral nutrition should be reserved for patients who are taking in sufficient calories yet are unable to tolerate oral or enteral protein-rich foods or formulas designed to meet daily protein requirements (> or = 1.5 g/kg in some patients). Intradialytic parenteral nutrition should not be prescribed in place of total parenteral nutrition (TPN) if the latter is truly needed. Creative methods of nutrition support, including the use of dietary supplements at dialysis (intradialytic oral or enteral nutrition), should be explored. Prospective clinical trials investigating the effects of nutrition support on survival, hospitalization rates, health-related quality of life, and functional status, are urgently needed.

Relationship of dialysis membrane and cause-specific mortality

A number of studies have suggested that type of dialysis membrane is associated with differences in long-term outcome of patients undergoing hemodialysis, both in terms of morbidity and mortality. The purpose of this study was to determine the relationship of membrane type and specific causes of death. Data from the United States Renal Data System Case Mix Adequacy Study, a national random sample of hemodialysis patients who were alive on December 31, 1990, were used. Our study was limited to patients in this data set who were undergoing dialysis for at least 1 year (n = 4,055). For the main analytic models, membrane type was classified into two categories: unmodified cellulose or MC/SYN (which combines modified cellulose [MC] and synthetic membranes [SYN]). The relationships of membrane type and major causes of mortality were analyzed using Cox proportional hazards models, which adjusted for multiple (21) covariates, including demographics, comorbidity, Kt/V, and other parameters. Patients were censored at transplantation or 60 days after a switch to peritoneal dialysis. Compared with patients dialyzed with unmodified cellulose membranes, the adjusted relative mortality risk (RR) from infection was 31% lower (RR = 0.69; P = 0.03) and from coronary artery disease was 26% lower (RR = 0.74; P = 0.07) for patients dialyzed with MC/SYN membranes. No statistically significant difference (all P > 0.1) was found in mortality risk from cerebrovascular disease (RR = 1.08), other cardiac causes (RR = 0.86), malignancy (RR = 0.90), or other known causes (RR = 0.82) between patients dialyzed with MC/SYN compared with unmodified cellulose membranes. These results offer support to reported experimental and observational clinical studies that have found that unmodified cellulose membranes may increase the risk for both infection and atherogenesis. Further studies are necessary to evaluate the possibility of confounding factors, compare more specific membrane types, and determine the pathophysiology linking membrane type to cause-specific mortality.

Blood pressure, left ventricular hypertrophy and long-term prognosis in hemodialysis patients

Cardiovascular events are the main cause of death in patients with chronic renal failure who are treated with hemodialysis. Hypertension is frequent among dialysis patients and may be a major cause of mortality, although epidemiological studies are controversial in this regard. This disparity in results may be the consequence of an inadequate definition of hypertension in dialysis patients as well as the interaction with hypertension with other risk factors such as malnutrition or left ventricular hypertrophy (LVH), which are strong predictors of death. Although the goal of blood pressure in dialysis has not been established yet, it seems that predialysis blood pressure levels lower than 150/90 mm Hg must be achieved for patients to avoid complications. LVH is very frequent among dialysis patients and starts early in the progression of chronic renal failure. Hypertension is the main cause for its development, but other potentially reversible factors such as anemia, volume overload, secondary hyperparathyroidism, dose of dialysis or malnutrition may also be implicated. Hence, an adequate management of patients on hemodialysis must include the strict control of blood pressure, preferably with angiotensin converting enzyme (ACE) inhibitors, together with those early measures in order to avoid the development of the other causes of LVH or to treat them when they already exist.

Hemodialysis access failure: a call to action

Recent evidence suggests that the cost as well as the morbidity associated with the maintenance of hemodialysis access is increasing rapidly; currently, the cost exceeds 1 billion dollars and access related hospitalization accounts for 25% of all hospital admissions in the U.S.A. This increase in cost and morbidity has been associated with several epidemiological trends that may contribute to access failure. These include late patient referral to nephrologists and surgeons, late planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts and temporary catheters, which have a higher failure rate. The reasons for this shift in the types of access is multifactorial and is not explained by changes in the co-morbidities of patients presenting to dialysis. Surgical preference and training also appear to play an important role in the large regional variation and patency rate of these PTFE grafts. We propose a program for early placement of A-V fistulae, a continuous quality improvement, multidisciplinary program to monitor access outcome, the development of new biomaterials, and a research plan to investigate pharmacological intervention to reduce development of stenosis and clinical interventions to treat those that do develop, prior to thrombosis.

[Cardiac pathology of extracardiac origin (IX)> Cardiac pathology in the patient with chronic nephropathy]

Cardiac disease constitutes a common complication among patients with renal failure. This is partly due to the high incidence of shared risk factors, such as hypertension or diabetes mellitus, and some to specific factors inherent in renal disease. It implies a high incidence of cardiac failure and ischemic heart disease (frequently without significant coronary artery obstructions) with important associated morbidity and mortality. Pericardial disease, valvular involvement and arrhythmia are also common among these patients. The management of these complications in patients with endstage renal disease has some particularities, specially in the field of drug therapy.

A multidisciplinary approach to hemodialysis access: prospective evaluation

Dialysis access procedures and complications represent a major cause of morbidity, hospitalization and cost for chronic dialysis patients. To improve outcomes and reduce the cost of hemodialysis access procedures we developed a multidisciplinary approach, involving nephrologists, access surgeons, and radiologists. A full-time dialysis access coordinator scheduled all access procedures with the surgeons and radiologists, and tracked outcomes. A computerized database was developed for prospective documentation of procedures and complications. Confidential, detailed analyses and recommendations for improvements were provided periodically to the surgeons and radiologists. The major changes arising from the multidisciplinary approach were as follows: (1) The approach to clotted grafts evolved from an inpatient surgical procedure to an outpatient radiologic procedure. The immediate technical success rate of graft declots increased from 48% to 69%. (2) Elective placement of arteriovenous (A-V) grafts evolved from a three-day inpatient hospitalization to a largely outpatient procedure. The proportion of A-V grafts placed as same day surgery or outpatient surgery increased from 16% to 81%. (3) Surgical complications of new A-V graft surgery decreased from 25% to 11%. (4) Aggressive detection and correction of graft stenosis decreased the incidence of graft thrombosis by 60%, from 0.70 to 0.28 events per patient-year. (5) The proportion of native A-V fistula construction in new dialysis patients increased from 33% to 69%. In conclusion, an integrated multidisciplinary approach markedly reduced surgical complications of access surgery and decreased access failures. These improvements occurred despite a marked decrease in hospitalization for access procedures, with a substantial cost saving.

Specificity of cardiac troponins I and T in renal disease

We investigated and compared serum levels of cardiac troponins I(cTnl) and cardiac troponin T (cTnT) in 85 renal patients (chronic renal impairment n = 23, continuous ambulatory peritoneal dialysis n = 20, hemodialysis n = 42). Patients with the following conditions were excluded: myocardial infarction, angina pectoris, liver disease, malignant neoplasms, enforced physical activity, skeletal muscle trauma, myositis, rhabdomyolysis and seizures. Troponin T was measured by the second generation cTnT-ELISA with a cut-off value = 0.1 microgram/l. Troponin I was measured by a cTnI immunoassay analyser with a cut-off value = 2.0 micrograms/l. Additionally, creatine kinase (CK), CK-MB activity, CK-MB mass concentration and myoglobin levels were measured. Specificity was determined as the fraction of true-negative cases compared to the total number of false-positive and true-negative cases. Specificity for cTnT was 96% [78-100] in patients with renal impairment (creatinine > 150 mumol/l), 95% [75-100] in continuous ambulatory peritoneal dialysis patients, but in hemodialysis patients it was 75% [53-92] for short-term hemodialysis (< 1 year) and 46% [24-68] for long-term hemodialysis (> 1 year). There was a weak correlation between cTnT levels and duration of hemodialysis therapy (r = 0.35, n = 34, p < 0.04). Specificity for cTnI in renal impairment patients was 96% [78-100] and 100% [84-100] in continuous ambulatory peritoneal dialysis and all hemodialysis patients. None of the studied markers showed higher specificity than cTnI. Only myoglobin was less specific than cTnT in hemodialysis patients. Different clearances of the troponins during dialysis (investigated by pre-hemodialysis and post-hemodialysis levels) cannot explain the discordant results of cTnT and cTnI.

CONCLUSION

Cardiac troponin I exhibits higher specificity than cardiac troponin T in hemodialysis patients. Uremic myopathy could explain falsely elevated troponin T levels in hemodialysis patients.

Bioimpedance norms for the hemodialysis population

More than 3,000 hemodialysis patients were examined with single-frequency bioelectrical impedance analysis (BIA). Distributions of resistance, reactance, phase angle (PA), and estimates of total body water (TBW) and body cell mass (BCM) by BIA were determined, and compared with traditional laboratory markers of nutritional status. Bioimpedance parameters and body composition estimates differed significantly by age, sex, race, and diabetic status. PA and BCM correlated directly with serum creatinine, albumin, and prealbumin concentrations. Population-based norms for bioimpedance parameters and estimates of body composition are provided.

An evidence-based approach to earlier initiation of dialysis

The objective was to review evidence addressing the optimal time to initiate dialysis treatment. The database was derived from an evidence-based review of the medical literature and from the Canada-United States peritoneal dialysis study. The publications were divided into (1) those addressing the clinical impact of early versus late referral to a dialysis program; (2) those evaluating the association between residual renal function at initiation of dialysis and the concurrent nutritional status; (3) those evaluating the association between residual renal function at initiation of dialysis and subsequent clinical outcomes, including patient survival. There were five studies evaluating early versus late referral, three cohort design and two case-control design. Late referrals had worse outcomes than early referrals. The former had more serious comorbidity and many had been noncompliant with follow-up. The latter were more likely to have hereditary renal disease. Renal function was slightly worse at initiation among those referred late. Three studies addressed the association between renal function at initiation of dialysis and concurrent nutritional status. Two showed decreased protein intake with diminished glomerular filtration rate (GFR). Poor nutritional status is associated with decreased patient survival among both incident and prevalent dialysis patients. The third study reported excellent patient survival among patients with late initiation of dialysis. These patients had received a supplemented low-protein diet and were not malnourished at initiation of dialysis. Three groups have studied the association between GFR at initiation of dialysis and clinical outcomes. Decreased GFR at initiation of dialysis is associated with a increased probability of hospitalization and death. None of these studies has used the rigorous randomized clinical trial design, and they are therefore subject to bias. Referral time bias, comorbidity, patient compliance, and starting time bias are potential confounders. A randomized clinical trial is required to resolve this important issue. However, there is sufficient evidence to justify initiation of dialysis at a Ccr of 9 to 14 mL/min if there is any clinical or laboratory evidence of malnutrition.

Left ventricular morphology in chronic renal failure by echocardiography

M-mode, two-dimensional, and Doppler echocardiography were performed in 38 chronic renal failure (CRD) patients on conservative management, 35 patients on hemodialysis, and 36 matched controls. The controls were matched for age, sex, and comorbidities. The incidence of hypertension, left ventricular (LV) end diastolic volume, LV end systolic volume, and LV mass index were significantly higher in patients on hemodialysis compared to the controls. The LV parameters in the predialysis patients were not significantly different from the controls, except the LV end systolic internal dimensions were significantly higher in the CRF patients. Multiple regression analysis underscored the strong association between increase in LV mass index (LVMI) and hypertension. The diabetic patients with renal failure had large LV internal diameter and end diastolic volume compared to non-diabetics. Systolic function was well preserved even in hypertensive and diabetic patients with uremia. The incidence of diastolic dysfunction and asymmetrical septal hypertrophy were not significantly different in the three groups of patients.

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.

Cost-effectiveness of repeat medical procedures: kidney transplantation as an example

The constraints on medical-care resources can give rise to the question of the cost-effectiveness of permitting repeat medical procedures when some patients may die without undergoing even a first procedure. Using kidney transplantation as an example, this study estimates the cost-effectiveness of patients' having available the option of a repeat medical procedure in the event the first procedure fails. Specifically, the analysis examines the effect on transplant candidates of having the option of kidney retransplantation, if and when retransplantation might be needed. Data sources include the U.S. Renal Data System (USRDS) Case-Mix Severity Study, Health Care Financing Administration (HCFA) data, and a MEDLINE search. Outcome measures include life expectancy, quality-adjusted life expectancy, lifetime costs of medical care, and marginal cost-effectiveness from a societal perspective. By avoiding lifelong dialysis after graft failure, first-transplant candidates gain an average of 47 quality-adjusted days with a retransplantation policy, despite the prolongation of time to first transplant by an average of 30 quality-adjusted days. The lifetime cost of medical care per first-transplant candidate is $1,210 higher with a retransplantation policy compared with the no-retransplantation policy; its societal cost-effectiveness is estimated to be $9,656 per quality-adjusted life-year saved. The retransplantation policy provides the greatest improvement in quality-adjusted life expectancy for younger candidates. In the case of kidney transplantation, the cost-effectiveness of a repeat transplant, on average, compares favorably with those of other medical strategies in common practice. As resources become increasingly constrained, this study demonstrates a framework for considering the cost-effectiveness of repeat medical procedures.

Destructive pneumococcal septic arthritis in end-stage renal disease

Pneumococcal arthritis generally presents as non-destructive monoarthritis, although some underlying metabolic disorders such as liver failure and diabetes have been suggested to represent a risk factor for severe joint disease. Here we report a case of destructive pneumococcal arthritis of the left hip joint in a patient suffering from chronic renal failure treated with hemodialysis for ten years. Inspite of effective anti-pneumococcal antibiotic treatment, the patient with preexisting renal osteopathy and a mild osteoarthritis continued to suffer from severe and disabling pain of the left hip. This case demonstrates that pneumococcal joint infection in patients with underlying uremic bone disease can lead to quick deterioration of the affected joint.

Cardiac disease in chronic uremia: epidemiology

Cardiac abnormalities develop during chronic renal failure. The prevalence of ischemic heart disease, cardiac failure, and left ventricular disorders is high among patients initiating end-stage renal disease (ESRD) therapy, and appears to be getting higher. Age, gender, race, diabetes, and possibly geographic location are predictive of the presence of several cardiac conditions. Cardiac morbidity after the initiation of ESRD therapy is high, and cardiac causes are the most common reported cause of death. Cardiac abnormalities present on starting dialysis contribute to this morbidity and mortality. In epidemiological studies, higher cardiac death rates have also been associated with dialysis rather than transplantation as mode of ESRD therapy, peritoneal rather than hemodialysis, lower dose of dialysis, and unmodified cellulose rather than modified cellulose/synthetic hemodialysis membranes.

Vascular access survival among incident hemodialysis patients in the United States

Vascular access failure causes substantial morbidity to hemodialysis patients. We sought to identify factors determining survival of the permanent vascular access in use at the start of end-stage renal disease during 1990 in a national sample of 784 incident hemodialysis patients insured by Medicare. Medicare claims records were used to identify access failures or revisions among patients with an arteriovenous (AV) fistula (n = 245) and an AV vascular graft (n = 539). A proportional hazards analysis of time to first failure or revision, controlled by stratification for sex, race, and cause of end-stage renal disease, was used to determine the effect of age, access type, and peripheral vascular disease on vascular access survival. Patients with an AV fistula and who were older than 65 years had a risk of access failure that was 24% lower than similar patients with an AV graft (P < 0.02). The relative risk of access failure for an AV fistula, but not an AV graft, varied significantly with age for patients younger than 65 years (P < 0.01). The relative risk of access failure for a patient with an AV fistula, compared with a patient of the same age with an AV graft, was 67% lower at the age of 40 years, 54% lower at the age of 50 years, and 24% lower at the age of 65 years. A history of peripheral vascular disease was associated with a 24% higher risk of AV graft or fistula failure (P = 0.05). Measures to decrease vascular access-related morbidity among hemodialysis patients should include reversing the current trend toward increasing use of AV grafts, particularly in patients younger than 65 years.

Cardiac disease in chronic uremia: pathogenesis

Cardiomyopathy in chronic uremia results from pressure and volume overload. The former causes concentric left ventricular [LV] hypertrophy, results from hypertension and aortic stenosis, and is also associated with diabetes mellitus and anemia. Volume overload causes LV dilatation, results from arteriovenous shunting, salt and water overload, and anemia, and is also associated with ischemic heart disease, hypertension, and hypoalbuminemia. Decreased major arterial compliance and an early return of arterial wave reflections are also associated with the extent of LV hypertrophy. Cardiomyopathy predisposes to diastolic and systolic dysfunction. The latter results from myocyte death, and predisposing factors include ischemic heart disease and the uremic environment. Ischemic heart disease may be atherosclerotic or nonatherosclerotic in origin. Multiple factors contribute to the vascular pathology of chronic uremia, including injury to the vessel wall, dyslipidemia, prothrombotic factors, increased oxidant stress, and hyperhomocysteinemia. Ischemic risk factors include hypertension, LV hypertrophy, hypoalbuminemia, and perhaps hyperparathyroidism. The clinical consequences of cardiomyopathy include heart failure, ischemic heart disease, dialysis hypotension, and arrhythmias. The adverse impact of ischemic heart disease is probably mediated through the development of cardiac failure.

Cardiac disease in chronic uremia: clinical outcome and risk factors

Cardiac disease is common and is the major killer in end-stage renal disease (ESRD). Cardiac failure is a highly malignant condition in ESRD patients. Cardiac failure mediates most of the adverse prognostic impact of ischemic heart disease. Left ventricular (LV) abnormalities are already present at initiation of dialysis therapy in approximately 80% of patients. These abnormalities (ie, systolic dysfunction in approximately 15%, LV dilatation with preserved systolic function in 30%, concentric LV hypertrophy [LVH] in 40%) independently predict ischemic heart disease and cardiac failure, and are the largest baseline predictor of mortality after 2 years on dialysis therapy. The associations between classical risk factors (eg, hyperlipidemia, smoking, hypertension) and cardiac outcomes in ESRD are inconsistent. "Uremic" risk factors represent a nascent, but potentially important field. In our prospective 10-year study of 433 patients starting renal replacement therapy, we identified the following as major independent risk factors for cardiac disease: (1) hypertension (concentric LVH, LV dilatation, ischemic heart disease, cardiac failure, inverse relationship with mortality); (2) anemia (LV dilatation, cardiac failure, death); and (3) hypoalbuminemia (ischemic heart disease, cardiac failure, death). Transplantation dramatically improved LV abnormalities, suggesting that a uremic environment is cardiotoxic. Multiple risk factors act in concert to produce cardiac disease in ESRD; many of these are avoidable, suggesting that the enormous burden of disease can be reduced considerably.

Polyurethane catheters for long-term hemodialysis access

Chronic hemodialysis patients with failed native fistulas and/or synthetic arteriovenous grafts are usually dialyzed via surgically placed silicone jugular catheters such as the PermCath (Quinton, Seattle, WA, U.S.A.). We report a successful experience with the use of double lumen polyurethane central venous catheters placed percutaneously. Catheters with poor flows were replaced over a guidewire at the bedside. Eleven long-term hemodialysis patients failed arteriovenous access, 9 of them having had multiple attempts at fistulas and/or grafts. Seven of these patients had also failed peritoneal dialysis. They were dialyzed with polyurethane catheters for a mean of 681 +/- 280 days (range 282-1150 days), requiring a mean of 3.4 +/- 0.4 new venous punctures and 8.2 +/- 1.5 catheter changes over a guidewire over that period of time. Actuarial patient survival was 50% at 2 years, and mean urea reduction during dialysis was 64.2 +/- 1.7%. The septicemia rate was only 1.2 episodes per 1,000 catheter-days, but about 20% of patients experienced central venous occlusion, attributable to the use of subclavian catheter placement in 82% of the sites. The success of this technique and its elimination of the need for urokinase, radiologic interventions, and surgical placement warrant its consideration as an acceptable form of long-term vascular access, provided jugular placement allows reduced central venous occlusion rates.

Using nursing diagnoses to achieve desired outcomes for hemodialysis clients

As part of the multidisciplinary end-stage renal disease (ESRD) health care team, nephrology nurses assess, diagnose, plan, implement, and evaluate nursing care for hemodialysis clients. As the team member with the most consistent contact with the client, registered nurses not only practice within their own unique domain but also refer to medical, nutritional, and social work staff. Use of the taxonomy of nursing diagnosis provides a framework for nurses to identify client problems and risk factors that they can treat independently. The use of client surveys specific to the Health Care Financing Administration (HCFA) core indicators: anemia, low albumin, treatment adequacy, and hypertension, enhances collection of subjective data from patients and increases their participation in care planning. Nursing diagnoses common to clients with these four conditions and related nursing interventions are presented in this article.

Low diastolic blood pressure, hypoalbuminemia, and risk of death in a cohort of chronic hemodialysis patients

In a previous report, we showed that nutritional status and especially serum albumin had great predictive value for death in chronic hemodialysis patients, whereas blood pressure did not. In the present study, we analyzed the causes of death in consideration of the relationship between serum albumin and blood pressure. A total of 1,243 Okinawan patients (719 males, 524 females) undergoing hemodialysis in January 1991 were followed up through the end of 1995. Three hundred forty-two of the patients died, 45 received transplants, and 12 were transferred by the end of the follow-up period. The total duration of observation was 5,110.3 patient-years. Blood pressure as well as clinical and laboratory variables were determined immediately prior to the first dialysis session in January 1991. The crude death rate was 40.0% when the diastolic blood pressure (DBP) <70 mm Hg, 35.0% at 70 to 79 mm Hg, 25.0% at 80 to 89 mm Hg, 25.0% at 90 to 99 mm Hg, and 13.0% at >100 mm Hg. The death rate showed an inverse correlation with DBP. DBP showed a significant positive correlation with serum albumin (r = 0.137, P < 0.001) and age (r = -0.325, P < 0.0001). The adjusted odds ratio (95% confidence interval) of death was 0.84 (0.71 to 0.99) with 10 mm Hg increments in DBP when the reference DBP was less than 69 mm Hg. Low DBP may be a manifestation of malnutrition and/or cardiovascular disease in chronic hemodialysis patients. Target DBP levels may be higher levels in chronic hemodialysis patients than the general population.

Risk factors of end-stage renal disease and serum creatinine in a community-based mass screening

This study evaluated risk factors for end-stage renal disease (ESRD) and the prognostic significance of serum creatinine levels in a community-based mass screening. We used the registries of both community-based mass screening and chronic dialysis programs. In 1983, a total of 107,192 subjects over 18 years of age (51,122 men and 56,070 women) participated in a mass-screening program in Okinawa, Japan. Among them, serum creatinine data were available for 14,609 participants (5,613 men and 8,996 women). During 10 years of follow-up, we identified 60 dialysis patients (29 men and 31 women) among this group. Logistic regression analysis on the risk of ESRD was performed to determine the significance of serum creatinine levels in comparison with other clinical variables. The adjusted odds ratio (95% confidence interval) was 5.31 (3.39 to 8.32) in men and 3.92 (2.88 to 5.34) in women when compared to baseline serum creatinine levels of less than 1.0 mg/dl in women and 1.2 mg/dl in men. Diastolic blood pressure was not a significant predictor of ESRD. Results demonstrated the prognostic significance of serum creatinine in a community-based mass screening. Gender difference in the incidence of ESRD was explained, at least partly, by differences between clinical predictors and baseline serum creatinine levels.

Serum and urine albumin: a progress report on their measurement and clinical significance

For about 25 years, bromcresol green and bromcresol purple have been the basis for most of the measurements of serum albumin in the US and perhaps in the world. The longevity of the methods is due to their being simple, sensitive, specific, inexpensive and relatively free from interferences. The lack of change in the serum albumin methodology is balanced by two important developments. First, the recognition of the importance of serum albumin in the maintenance of good health, and the association of decreased concentrations with increased risk of morbidity and mortality. Second, the association of albuminuria with diabetic nephropathy, which without medical intervention could lead to end-stage renal disease. The development of accurate and precise methods for urinary albumin has provided a tool to physicians to extend the length and improve the quality of life of many diabetic individuals.

Prediction of early death in end-stage renal disease patients starting dialysis

Demand for dialysis for patients with end-stage renal disease is growing, as is the comorbidity of dialysis patients. Accurate prediction of those destined to die quickly despite dialysis could be useful to patients, providers, and society in making decisions about starting dialysis. To determine whether age and comorbidity accurately predict death within 6 months of first dialysis for end-stage renal disease, a prospective cohort study of 822 patients starting dialysis at one of 11 Canadian centers was performed. Patient characteristics were recorded at first dialysis. Follow-up continued until death or study end (at least 6 months after enrollment). One hundred thirteen of 822 (13.7%) patients died within 6 months. Although an existing scoring system predicted prognosis, adverse scores greater than 9 were found in only 9.7% of those who died; only 52% of those who scored higher than 9 died within 6 months. No score cutoff point combined high true-positive and low false-positive rates for predicting early death. Age, severity of heart failure or peripheral vascular disease, arrhythmias, malnutrition, malignancy, or myeloma were independent prognostic factors identified in multivariate models. However, the best fit discriminant and logistic models were also unable to accurately predict death within 6 months. Clinicians were very accurate in assigning patients to prognostic groups up to a 50% risk of death by 6 months, above which they tended to overestimate risk. However, clinicians were only marginally better than the predictive models in determining whether a given high-risk patient would die. The inability of a scoring system or clinical intuition to accurately predict death soon after starting dialysis for end-stage renal disease suggests that limiting access to dialysis on the basis of likely short survival may be inappropriate in Canada.

Prealbumin is the best nutritional predictor of survival in hemodialysis and peritoneal dialysis

Patients undergoing dialytic therapy for end-stage renal disease (ESRD) have greater morbidity and mortality than age-matched individuals with similar demographics in the general population. Risk factors for early death during treatment for ESRD include advanced age, diabetes, hypertension, and malnutrition. We questioned whether the level of serum prealbumin at the start of uremia therapy might serve as a marker of subsequent survival in patients treated with maintenance hemodialysis (HD) and peritoneal dialysis (PD). Study cohorts included 111 HD and 78 PD patients followed for up to 5 years. Selected demographic characteristics and biochemical variables were tested for correlation with survival in each cohort. Variables evaluated included age, race, gender, diabetic status, and serum concentrations of albumin, creatinine, cholesterol, and prealbumin. For comparison, expected survival was calculated with Cox proportional hazards analysis, which accounts for confounding variables. We found that a higher relative risk (RR) of death in HD patients correlated with older age, the diagnosis of diabetes, and a serum prealbumin < 30 mg/dL. In PD patients, older age and the presence of diabetes correlated with a higher RR of death than in the standard population. When nutritional variables were analyzed separately, prealbumin < 30 mg/dL was the strongest variable that predicted mortality in HD patients (RR = 2.64, P = 0.002) and also predicted increased risk of mortality in PD patients (RR = 1.8, P = 0.035). Observed and expected survival was significantly higher in patients with enrollment prealbumin greater than 30 mg/dL in both HD and PD. The serum prealbumin level correlated significantly with other measures of nutrition, including serum albumin, serum creatinine, and serum cholesterol, in both HD and PD patients. Among tested markers of nutritional status, prealbumin level appears to be the single best nutritional predictor of survival in ESRD patients.

Enrollment parathyroid hormone level is a new marker of survival in hemodialysis and peritoneal dialysis therapy for uremia

The relatively high morbidity and mortality during dialytic therapy for end-stage renal disease (ESRD) in the United States is the subject of current inquiry. Identified risk factors for excess mortality include advanced age, diabetes, and malnutrition exemplified by a low serum albumin level. Parathyroid hormone (PTH) has long been thought to contribute to the toxicity of the uremic syndrome. We reviewed the course of patients maintained by hemodialysis (HD) and peritoneal dialysis (PD) to detect any correlation between the level of PTH when beginning dialytic therapy and subsequent morbidity and mortality. Study cohorts consisted of 175 HD and 113 PD patients followed for up to 9 years. Demographic characteristics such as age, race, gender, diabetic status, and prior months on dialysis, as well as biochemical parameters including albumin, creatinine, cholesterol, intact PTH, calcium, and phosphorus levels at enrollment were evaluated for their effect on patient survival. Expected survival was calculated by Cox proportional hazards analysis. Older age and lower enrollment serum creatinine level were associated with increased mortality in both HD and PD patients, whereas low serum albumin and low serum cholesterol levels also predicted high mortality in HD patients. In both HD and PD, patients with enrollment PTH level of < or = 65 pg/mL had more than twice the mortality risk of those with PTH > or = 200 pg/mL. Both observed and expected survival of patients with low PTH were significantly lower than the survival in patients with higher PTH. Five-year HD survivors and four-year PD survivors had significantly higher PTH levels at initiation of dialytic therapy than did those with shorter survival. PTH level correlated with serum creatinine and serum albumin in HD but only with serum creatinine in PD, supporting the inference that patients with high enrollment PTH were better nourished than those with lower PTH.

Modeling mortality risk in hemodialysis patients using laboratory values as time-dependent covariates

Proportional hazards analyses assume that the magnitude of mortality risk for a predictor variable remains proportional over time. In a time-dependent model, the explanatory variable violates this assumption, and repeat observations are required to accommodate the change in risk that occurs over time. Using a retrospective cohort design, we tested the following laboratory values for a time-by-covariate interaction: hematocrit (HCT), serum albumin (ALB), and serum creatinine (CR). A random sample of 4,083 hemodialysis patients whose specimens were analyzed in a central laboratory over a 3-year period served as the study group. Using the baseline observation, we discovered significant probability values for the interaction terms TIME*CR (P = 0.013) and TIME*ALB (P < 0.01). The beta coefficient for TIME*HCT was not significant, indicating that the proportional hazard assumption was not violated by this covariate. Based on these results, we fitted a multivariate regression model containing two time-dependent covariates (CR and ALB) using a data structure that incorporated repeat observations of these laboratory values. Patients with high ALB levels experienced the lowest mortality risk. Similarly, serum CR levels were higher in long-term survivors. This analysis verifies the clinical importance of monitoring ALB and CR levels over time and the hazard of using a single laboratory observation to make long-term projections. Additionally, the predictive values of the time-dependent covariates ALB and CR affirm the significance of nutritional approaches directed toward maintaining visceral and somatic protein content throughout renal replacement therapy.