Survival In Chronic Hemodialysis Patients Research Articles

Correlates affecting survival in chronic hemodialysis patients: The combined impact of albumin and high hemoglobin levels on improving outcomes, local and national results

While national mortality rates for end-stage renal disease (ESRD) patients remain high, for the past 4 years, lower than expected local mortality rates have been consistently seen in our facilities. Because of these progressive improvements in mortality rates, a study of 687 hemodialysis patients over a 4-year period, 2003 through 2006, was undertaken to analyze which factors may be contributing to the enhanced survival rates. We also examined the partially overlapping United States Renal Data System clinical performance measures national data sets of hemodialysis patients for 2001 to 2004. Proportional hazards and logistic regression models were used to determine significant predictors of short-term survival. Variables tested included hemoglobin (Hb), albumin, calcium, phosphorus, infections, hospitalizations, URR, Kt/V, erythropoietic stimulating agents (epoetin-alpha) use, and comorbid conditions. The local and national models identified albumin, Hgb, and hospitalization as statistically significant predictors of survival. Local models also found years of dialysis as a significant predictor. Locally, there was a 69-fold increase from 16.1 deaths/1000 patient years for albumin > or =4.0 with Hgb> or =14.0 to 1115.9 deaths/1000 patient-years for albumin <3.5 with Hgb<11.0. The increase nationally is a 4-fold increase from 96 deaths/1000 patient-years for albumin > or =4.0 with Hgb> or =14.0 to 406 deaths/1000 patient-years for albumin <3.5 with Hgb<11.0. There was no evidence that higher erythropoietic stimulating agents dose levels were associated with higher mortality rates, independent of the other significant factors. In conclusion, the findings indicate that individually higher Hgb and albumin levels are associated with increased survival, and when higher Hgb levels are in association with high albumin levels, the survival rates and hospitalizations are synergistically improved.

Effects of Serum Calcium, Phosphorous, and Intact Parathyroid Hormone Levels on Survival in Chronic Hemodialysis Patients in Japan

Disturbances in bone mineral metabolism are common in chronic hemodialysis (HD) patients and often underlie morbid conditions and mortality; however, no large epidemiological study for Asian dialysis patients has been performed. We analyzed the database of the Japanese Society for Dialysis Therapy registry. In this study, data from patients who were on HD at the end of 2000 was compiled. The Cox's proportional hazard analysis was carried out to evaluate the significance of the impact of variables related to bone mineral metabolism on survival after adjusting for possible confounding variables. The study period was three years, and a cohort of 27 404 HD patients was studied. The hazard ratios were 1.098 (P = 0.0129) for serum calcium levels ranging 10.0-10.9 mg/dL, and 1.243 (P = 0.0001) for serum calcium levels >11.0 mg/dL when the reference serum calcium level range was 9.0-9.9 mg/dL. Similarly, the hazard ratios were significantly higher in a serum phosphorous level of 5.0 mg/dL than for the reference serum phosphorous level range of 4.0-4.9 mg/dL. For intact parathyroid hormone (iPTH), the hazard ratios were significantly small (<119 pg/mL) when the reference iPTH level range was 180-359 pg/mL. However, the hazard ratio did not increase when the iPTH level increased to >360 pg/mL. Results showed that disturbances in bone mineral metabolism, such as those involving serum calcium, phosphorous, and iPTH, have a significant impact on survival in Japanese dialysis patients.

The Impact of Visceral Mass on Survival in Chronic Hemodialysis Patients

In chronic hemodialysis, patient survival is positively correlated with body weight and body mass index (BMI). This relationship extends even to obese patients with a BMI >30 kg/m2. We have put forward the hypothesis that this survival benefit may be due to a lower average synthesis rate of uremic toxins (expressed as amount per time per unit of body weight) in larger patients, because the relative contribution of the high metabolic rate organs (HMRO) to body weight in these patients is lower and HMRO are most likely to be the prime source of uremic toxins. In addition, the average uremic toxin concentration in larger patients may be lower because of the larger distribution volume. Based on these assumptions, a better survival in patients with a lower HMRO to body weight fraction (HMRO%BW) can be predicted. To test this hypothesis we estimated gender- and race-specific HMRO mass by means of recently published regression models in 2,004 incident hemodialysis patients. Cox proportional hazards models were used to assess the association between age, serum albumin concentration, eKt/V, and HMRO% BW and mortality. High HMRO%BW was significantly associated with increased mortality (hazard ratio 1.323 [95% CI: 1.186 to 1.477]). Mean survival time was longest in the low HMRO%BW tertile (1,031 days [95%CI: 974 to 1,087]), 935 days [95%CI: 886 to 984] in the middle, and 876 days [95%CI: 825 to 926] in the high HMRO%BW tertile (p<0.0001; log rank test). These results support the hypothesis predicting that a low HMRO mass per unit of weight confers a beneficial effect on survival.

Hypertension and survival in chronic hemodialysis patients—Past lessons and future opportunities

There is substantial controversy surrounding the benefits of control of hypertension in hemodialysis patients. Unlike the general population, some studies suggest that higher blood pressure in hemodialysis patients offers a survival advantage, what is termed as "reverse epidemiology." To critically analyze the relationship between total and cardiovascular mortality and blood pressure, peer-reviewed, published studies in hemodialysis patients were analyzed. Consideration of the world-wide experience suggests that analysis of incident cohorts reveal a clear link between elevated blood pressure and mortality. Increased pulse pressure, which is primarily due to increased systolic pressure, is also associated with cardiovascular morbidity and mortality. The counterintuitive relationship between blood pressure and mortality appears, in part, to be due to methods of data analysis. When data are analyzed with systolic or diastolic blood pressure as separate models, not conjointly, inverse relationship between blood pressure and total and cardiovascular mortality is generally seen. When both systolic and diastolic blood pressure are considered together, systolic blood pressure or increased pulse pressure assumes a major importance in predicting cardiovascular events whereas diastolic blood pressure retains the inverse relationship. Control of hypertension in hypertensive dialysis patients is associated with improved survival. Furthermore, the use of antihypertensive drug treatment is associated with improved survival regardless of blood pressure control. Low predialysis blood pressure is associated with increased cardiovascular deaths and deaths within 2 years from malignancy or withdrawal from dialysis. These data suggest that hypertension needs to be better controlled in hypertensive hemodialysis patients. Better methods of assessment of blood pressure control, consideration of cardiac structure and function, and performance of randomized controlled trials of pharmacologic and nonpharmacologic strategies are needed to establish benefits and determining goal blood pressure in hemodialysis patients.

Effect of dialysis membranes and middle molecule removal on chronic hemodialysis patient survival.

The type of dialysis membrane used for routine therapy has been recently shown to correlate with the survival of chronic hemodialysis patients. We examined whether this effect of dialysis membrane could be explained by differences in dialyzer removal of middle molecules using data from the 1991 Case Mix Adequacy Study of the United States Renal Data System. The sample analyzed included patients who had been treated by hemodialysis for 1 year or more, who were dialyzed with the 19 most commonly used dialyzers in 1991, and for whom delivered urea Kt/V could be calculated from predialysis and postdialysis blood urea nitrogen concentrations. Vitamin B12 (1,355 daltons) was used as a marker for middle molecules, and the clearance of vitamin B12 was estimated based on in vitro data. After adjustments for case mix, comorbidities, and urea Kt/V, the relative risk of mortality for a 10% higher calculated total cleared volume of vitamin B12 was 0.953 (P < 0.0001 v 1.000). Similar results were obtained when middle molecule removal was adjusted for body size. We conclude that both small and middle molecule removal indices appear to be independently associated with the risk of mortality in chronic hemodialysis patients. Differences in mortality when using different types of dialysis membrane may be explained by differences in middle molecule removal.

What dialysis dose should be provided in acute renal failure? A review.

Increased dialysis dose has been shown to improve morbidity and survival in chronic hemodialysis patients. Despite improvement in care and technological aspects of renal replacement therapy, mortality rates of acute renal failure (ARF) have remained essentially unchanged for over two decades, exceeding 50% in most studies. The occurrence of ARF in older patients with more complicated medical and surgical conditions has contributed to this lack of outcome amelioration, and death of ARF patients is now more frequently caused by underlying disease than ARF itself. A recent prospective survey at this institution found a mortality rate of 79.1% among a total of 363 ARF medical and surgical intensive care unit patients, with a mean age near 60 years and a mean admission APACHE II score of over 20, who were treated by intermittent hemodialysis and continuous renal replacement therapy (CRRT). Nonsurvivors had a mean of over four failed systems, in addition to the renal failure, compared with survivors who had less than four. The standards for dialysis adequacy in ARF are not currently defined. Increased catabolism seen in ARF patients in the intensive care unit may justify large dialysis dose delivery. An apparent influence of delivered dialysis dose on the outcome of ARF intensive care unit patients has been recently observed at our institution. Compared with nonsurvivors, survivors had received significantly higher dialysis dose, as assessed by Kt/V and urea reduction ratio. In ARF patients, the discrepancy between delivered versus prescribed dialysis dose may be particularly important and contributed to by the following: reduced blood flow rate and dialysis time consequent to patient intolerance; lower dialyzer in vivo clearances, particularly in heparin-free dialysis; blood recirculation when using temporary vascular access; and postdialysis urea rebound. Prolonging the course of renal failure is one of the risks attributed to frequent dialysis; hypotension and ultrafiltration combined with a deficient renal autoregulation can result in further renal damage. The detrimental effects of bioincompatible membranes have been demonstrated with an induced-delay of renal function recovery. A recent study has reported benefits of biocompatible membranes in terms of potential for renal recovery and maintenance of urine output during dialytic support when compared with bioincompatible membranes. CRRT offers many advantages over intermittent hemodialysis for ARF intensive care unit patients: better hemodynamic tolerance, avoidance of solute rebound, and removal of serum sepsis mediators. However, CRRT have not yet been firmly shown to improve survival rates. Recently, urea kinetics have been used to estimate dialysis dose provided by CRRT.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum albumin is a strong predictor of death in chronic dialysis patients

We examined the predictive value of various clinical variables in assessing survival in chronic hemodialysis patients (N = 1,243, 524 females, 719 males) who were under treatment with hemodialysis as of January 1991 in Okinawa, Japan and who were followed up until April 1992. Basal clinical data such as sex, starting date of dialysis, primary renal disease, blood pressure, blood chemistry values, and dialysis prescription data obtained just prior to dialysis were registered at the start of the study. As of the end of April 1992, 104 had died, 16 were transplant recipients, and five had been transferred. Those who died had significantly lower levels of total protein, serum albumin, total cholesterol, triglyceride, BUN, serum creatinine, body weight, body height, diastolic blood pressure, and duration of hemodialysis than those who survived. Older patients and those with diabetes mellitus had a poorer prognosis. A forward stepwise logistic procedure by SAS was used to determine the predictive value of the above clinical variables. With the addition of laboratory variables, the predictive value of diabetes was lost, as the diabetic patients had low serum levels of albumin and creatinine. The standardized coefficient was -0.380 (P = 0.0001) at age of entry, 0.316 (P = 0.0001) for serum albumin, 0.280 (P = 0.0001) for serum creatinine, 0.138 (P = 0.043) for body mass index (BMI), and -0.139 (P = 0.016) for male sex. The prescribed dialysis dose (M2 hr per week) was significantly correlated with serum creatinine (r = 0.48, P = 0.0001), serum albumin (r = 0.135, P = 0.0001) and BMI (r = 0.275, P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)