Information from a large clinical database was used to construct time trends for the leading asso... more Information from a large clinical database was used to construct time trends for the leading associates of mortality among dialysis patients. The changing strengths of association of those measures with mortal risk were also evaluated. Strength did not change in meaningful ways for serum albumin, creatinine, or anion gap concentrations. It declined for the urea reduction ratio (URR), however, as prevalent values of the URR increased. Irrational patterns of association between the URR and other measures suggested reevaluation of the urea kinetic method for prescribing and judging dialysis dose. Two premises on which the urea kinetic equations rest are not valid if the context for their use is clinical outcome instead of predicting blood urea nitrogen (BUN) concentration. Rigorous use of the Kt/V criterion for dialysis dose could lead to clinical judgment errors, particularly underdialysis for small or malnourished persons. Changes for prescribing dose and judging therapy are recommended. (Am J Kidney Dis 1998 Dec;32(6 Suppl 4):S16-31)
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1994
The mortality rate for hemodialysis patients in the United States is higher than in other industr... more The mortality rate for hemodialysis patients in the United States is higher than in other industrialized countries. Some attribute this to insufficient quantities of prescribed and delivered dialysis. A multicenter study in Dallas dialysis centers (Dallas Nephrology Associates) was begun in 1989 to assess the impact of increasing the delivered quantity of dialysis on mortality in subsequent years. Dialysis dose was measured by urea kinetic modeling. Kt/V, reflecting the fractional volume of body water clearance of urea during a dialysis treatment, was purposefully increased from 1.18 starting in 1989 to 1.46 in 1992. Additionally, the dialysis dose measured by the urea reduction ratio, the fractional reduction of blood urea nitrogen concentration caused by a dialysis treatment, increased from 63.0% to 69.6% between 1990 and 1992. Outcome analytical methods included both crude and standardized mortality rates and mortality ratios standardized to large end-stage renal disease database...
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1994
Hemodialysis patients who had received intradialytic parenteral nutrition (IDPN) during 1991 were... more Hemodialysis patients who had received intradialytic parenteral nutrition (IDPN) during 1991 were identified. These patients were compared with unexposed controls after adjusting for demographic variables, baseline renal diagnosis, diabetic status, serum albumin (ALB), creatinine (CRE), and urea reduction ratio. At lower levels of ALB (< or = 3.4 g/dL), treatment with IDPN was associated with a reduction in the odds of death at 1 year, an effect that became stronger at lower levels of CRE (< or = 8.0 mg/dL). In contrast, treatment with IDPN in patients with normal ALB was associated with increased mortality. Time trend analyses of ALB and CRE demonstrated progressive increases toward pretreatment levels in IDPN recipients that were not evident in control subjects. These time trend data suggest that in undernourished hemodialysis patients, IDPN can effect the serum levels of valid biochemical surrogates of visceral and somatic protein nutrition. Albeit retrospective, the improv...
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1990
Logistic regression analysis was applied to a sample of more than 12,000 hemodialysis patients to... more Logistic regression analysis was applied to a sample of more than 12,000 hemodialysis patients to evaluate the association of various patient descriptors, treatment time (hours/treatment), and various laboratory tests with the probability of death. Advancing age, white race, and diabetes were all associated with a significantly increased risk of death. Short dialysis times were also associated with high death risk before adjustment for the value of laboratory tests. Of the laboratory variables, low serum albumin less than 40 g/L (less than 4.0 g/dL) was most highly associated with death probability. About two thirds of patients had low albumin. These findings suggest that inadequate nutrition may be an important contributing factor to the mortality suffered by hemodialysis patients. The relative risk profiles for other laboratory tests are presented. Among these, low serum creatinine, not high, was associated with high death risk. Both serum albumin concentration and creatinine were...
To determine the relation between phase angle by bioelectrical impedance analysis (BIA) and survi... more To determine the relation between phase angle by bioelectrical impedance analysis (BIA) and survival in hemodialysis patients.
Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance d... more Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance during dialysis and nutritional adequacy are determinants of mortality. We determined the effects of reductions in blood urea nitrogen concentrations during dialysis and changes in serum albumin concentrations, as an indicator of nutritional status, on mortality in a large group of patients treated with hemodialysis. We analyzed retrospectively the demographic characteristics, mortality rate, duration of hemodialysis, serum albumin concentration, and urea reduction ratio (defined as the percent reduction in blood urea nitrogen concentration during a single dialysis treatment) in 13,473 patients treated from October 1, 1990, through March 31, 1991. The risk of death was determined as a function of the urea reduction ratio and serum albumin concentration. As compared with patients with urea reduction ratios of 65 to 69 percent, patients with values below 60 percent had a higher risk of death during follow-up (odds ratio, 1.28 for urea reduction ratios of 55 to 59 percent and 1.39 for ratios below 55 percent). Fifty-five percent of the patients had urea reduction ratios below 60 percent. The duration of dialysis was not predictive of mortality. The serum albumin concentration was a more powerful (21 times greater) predictor of death than the urea reduction ratio, and 60 percent of the patients had serum albumin concentrations predictive of an increased risk of death (values below 4.0 g per deciliter). The odds ratio for death was 1.48 for serum albumin concentrations of 3.5 to 3.9 g per deciliter and 3.13 for concentrations of 3.0 to 3.4 g per deciliter. Diabetic patients had lower serum albumin concentrations and urea reduction ratios than nondiabetic patients. Low urea reduction ratios during dialysis are associated with increased odds ratios for death. These risks are worsened by inadequate nutrition.
Development of a population specific regression equation to estimate total body water in hemodial... more Development of a population specific regression equation to estimate total body water in hemodialysis patients. We have previously shown that the impedance index (height corrected resistance) is a valid and reliable correlate of total body water (TBW) in hemodialysis patients. We estimated TBW by single frequency bioelectrical impedance analysis (BIA) in 3009 in-center hemodialysis patients, and developed an ESRDspecific TBW equation from routinely available demographic and anthropometric variables. The mean SD age was 60.5 15.5 years; 47% were female, 47% African-American, and 36% diabetic. Dialysis duration was 3.8 3.7 years. Mean TBW was 40.8 9.3 kg, 56 9% of body weight. A stepwise linear regression equation was fit on a two-thirds random sample, deriving significant parameter estimates for the variables age, gender, height, weight, diabetic status, weight squared, and the crossproducts of age and gender, age and weight, gender and weight, and height and weight. The equation was then validated in the remaining one-third sample, and compared with TBW estimates by the Watson and Hume-Weycr formulae. TBW estimated by our equation (40.6 8.6 kg) was not significantly different from the BIA TBW (40.5 9.3 kg). In contrast, TBW estimated by the Watson (37.0 7.6 kg) and Hume-Weyer (37.9 7.7 kg) formulae underestimated TBW by a mean of 3.5 and 2.6 kg, respectively. A population-specific equation provides superior prediction of TBW in hemodialysis patients. The use of formulae developed and validated in non-uremic populations may result in underestimates of TBW in patients with ESRD, and potentially, overestimates of dialysis dose approximated by the clearance-time to TBW ratio (Kt/V).
Bioimpedance norms for the hemodialysis population. More than 3,000 hemodialysis patients were ex... more 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.
Peritoneal dialysis adequacy: A model to assess feasibility with weekly normalized urea clearance... more Peritoneal dialysis adequacy: A model to assess feasibility with weekly normalized urea clearance (Kprt/V) of 2.0 or various modalities. more and a creatinine clearance (C Cr ) of 60 liter/1.73 m 2
tive risk (RR) of death between two-and tenfold or ment of hemodialysis patients. more, depending... more tive risk (RR) of death between two-and tenfold or ment of hemodialysis patients. more, depending on the severity of PEM and the interac-Background. Although serum prealbumin is considered a tion of PEM with other factors (age, anemia, dialysis valid indicator of nutritional status in hemodialysis patients, vintage, etc.) [1-3]. Serum albumin has been the most there is relatively little evidence that its determination is of commonly employed marker of PEM, based largely on major prognostic significance. In this study, we aimed to determine the independent association of serum prealbumin with Key words: maintenance dialysis, protein energy malnutrition, serum line on Nutrition, the validity and clinical utility of several albumin, mortality and hemodialysis, chronic renal disease, adequacy of dialysis, dietary metabolic needs.
ity in those patients who are in the lower 50th percentile for Body weight-for-height relationshi... more ity in those patients who are in the lower 50th percentile for Body weight-for-height relationships predict mortality in mainthis measurement. tenance hemodialysis patients.
not) and also with increasing body size (whether adjusted for The urea {clearance ϫ dialysis time... more not) and also with increasing body size (whether adjusted for The urea {clearance ϫ dialysis time} product (Kt) as an outcome-Kt or not) for each estimate of size. Significant statistical interbased measure of hemodialysis dose.
Information from a large clinical database was used to construct time trends for the leading asso... more Information from a large clinical database was used to construct time trends for the leading associates of mortality among dialysis patients. The changing strengths of association of those measures with mortal risk were also evaluated. Strength did not change in meaningful ways for serum albumin, creatinine, or anion gap concentrations. It declined for the urea reduction ratio (URR), however, as prevalent values of the URR increased. Irrational patterns of association between the URR and other measures suggested reevaluation of the urea kinetic method for prescribing and judging dialysis dose. Two premises on which the urea kinetic equations rest are not valid if the context for their use is clinical outcome instead of predicting blood urea nitrogen (BUN) concentration. Rigorous use of the Kt/V criterion for dialysis dose could lead to clinical judgment errors, particularly underdialysis for small or malnourished persons. Changes for prescribing dose and judging therapy are recommended. (Am J Kidney Dis 1998 Dec;32(6 Suppl 4):S16-31)
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1994
The mortality rate for hemodialysis patients in the United States is higher than in other industr... more The mortality rate for hemodialysis patients in the United States is higher than in other industrialized countries. Some attribute this to insufficient quantities of prescribed and delivered dialysis. A multicenter study in Dallas dialysis centers (Dallas Nephrology Associates) was begun in 1989 to assess the impact of increasing the delivered quantity of dialysis on mortality in subsequent years. Dialysis dose was measured by urea kinetic modeling. Kt/V, reflecting the fractional volume of body water clearance of urea during a dialysis treatment, was purposefully increased from 1.18 starting in 1989 to 1.46 in 1992. Additionally, the dialysis dose measured by the urea reduction ratio, the fractional reduction of blood urea nitrogen concentration caused by a dialysis treatment, increased from 63.0% to 69.6% between 1990 and 1992. Outcome analytical methods included both crude and standardized mortality rates and mortality ratios standardized to large end-stage renal disease database...
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1994
Hemodialysis patients who had received intradialytic parenteral nutrition (IDPN) during 1991 were... more Hemodialysis patients who had received intradialytic parenteral nutrition (IDPN) during 1991 were identified. These patients were compared with unexposed controls after adjusting for demographic variables, baseline renal diagnosis, diabetic status, serum albumin (ALB), creatinine (CRE), and urea reduction ratio. At lower levels of ALB (< or = 3.4 g/dL), treatment with IDPN was associated with a reduction in the odds of death at 1 year, an effect that became stronger at lower levels of CRE (< or = 8.0 mg/dL). In contrast, treatment with IDPN in patients with normal ALB was associated with increased mortality. Time trend analyses of ALB and CRE demonstrated progressive increases toward pretreatment levels in IDPN recipients that were not evident in control subjects. These time trend data suggest that in undernourished hemodialysis patients, IDPN can effect the serum levels of valid biochemical surrogates of visceral and somatic protein nutrition. Albeit retrospective, the improv...
American journal of kidney diseases : the official journal of the National Kidney Foundation, 1990
Logistic regression analysis was applied to a sample of more than 12,000 hemodialysis patients to... more Logistic regression analysis was applied to a sample of more than 12,000 hemodialysis patients to evaluate the association of various patient descriptors, treatment time (hours/treatment), and various laboratory tests with the probability of death. Advancing age, white race, and diabetes were all associated with a significantly increased risk of death. Short dialysis times were also associated with high death risk before adjustment for the value of laboratory tests. Of the laboratory variables, low serum albumin less than 40 g/L (less than 4.0 g/dL) was most highly associated with death probability. About two thirds of patients had low albumin. These findings suggest that inadequate nutrition may be an important contributing factor to the mortality suffered by hemodialysis patients. The relative risk profiles for other laboratory tests are presented. Among these, low serum creatinine, not high, was associated with high death risk. Both serum albumin concentration and creatinine were...
To determine the relation between phase angle by bioelectrical impedance analysis (BIA) and survi... more To determine the relation between phase angle by bioelectrical impedance analysis (BIA) and survival in hemodialysis patients.
Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance d... more Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance during dialysis and nutritional adequacy are determinants of mortality. We determined the effects of reductions in blood urea nitrogen concentrations during dialysis and changes in serum albumin concentrations, as an indicator of nutritional status, on mortality in a large group of patients treated with hemodialysis. We analyzed retrospectively the demographic characteristics, mortality rate, duration of hemodialysis, serum albumin concentration, and urea reduction ratio (defined as the percent reduction in blood urea nitrogen concentration during a single dialysis treatment) in 13,473 patients treated from October 1, 1990, through March 31, 1991. The risk of death was determined as a function of the urea reduction ratio and serum albumin concentration. As compared with patients with urea reduction ratios of 65 to 69 percent, patients with values below 60 percent had a higher risk of death during follow-up (odds ratio, 1.28 for urea reduction ratios of 55 to 59 percent and 1.39 for ratios below 55 percent). Fifty-five percent of the patients had urea reduction ratios below 60 percent. The duration of dialysis was not predictive of mortality. The serum albumin concentration was a more powerful (21 times greater) predictor of death than the urea reduction ratio, and 60 percent of the patients had serum albumin concentrations predictive of an increased risk of death (values below 4.0 g per deciliter). The odds ratio for death was 1.48 for serum albumin concentrations of 3.5 to 3.9 g per deciliter and 3.13 for concentrations of 3.0 to 3.4 g per deciliter. Diabetic patients had lower serum albumin concentrations and urea reduction ratios than nondiabetic patients. Low urea reduction ratios during dialysis are associated with increased odds ratios for death. These risks are worsened by inadequate nutrition.
Development of a population specific regression equation to estimate total body water in hemodial... more Development of a population specific regression equation to estimate total body water in hemodialysis patients. We have previously shown that the impedance index (height corrected resistance) is a valid and reliable correlate of total body water (TBW) in hemodialysis patients. We estimated TBW by single frequency bioelectrical impedance analysis (BIA) in 3009 in-center hemodialysis patients, and developed an ESRDspecific TBW equation from routinely available demographic and anthropometric variables. The mean SD age was 60.5 15.5 years; 47% were female, 47% African-American, and 36% diabetic. Dialysis duration was 3.8 3.7 years. Mean TBW was 40.8 9.3 kg, 56 9% of body weight. A stepwise linear regression equation was fit on a two-thirds random sample, deriving significant parameter estimates for the variables age, gender, height, weight, diabetic status, weight squared, and the crossproducts of age and gender, age and weight, gender and weight, and height and weight. The equation was then validated in the remaining one-third sample, and compared with TBW estimates by the Watson and Hume-Weycr formulae. TBW estimated by our equation (40.6 8.6 kg) was not significantly different from the BIA TBW (40.5 9.3 kg). In contrast, TBW estimated by the Watson (37.0 7.6 kg) and Hume-Weyer (37.9 7.7 kg) formulae underestimated TBW by a mean of 3.5 and 2.6 kg, respectively. A population-specific equation provides superior prediction of TBW in hemodialysis patients. The use of formulae developed and validated in non-uremic populations may result in underestimates of TBW in patients with ESRD, and potentially, overestimates of dialysis dose approximated by the clearance-time to TBW ratio (Kt/V).
Bioimpedance norms for the hemodialysis population. More than 3,000 hemodialysis patients were ex... more 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.
Peritoneal dialysis adequacy: A model to assess feasibility with weekly normalized urea clearance... more Peritoneal dialysis adequacy: A model to assess feasibility with weekly normalized urea clearance (Kprt/V) of 2.0 or various modalities. more and a creatinine clearance (C Cr ) of 60 liter/1.73 m 2
tive risk (RR) of death between two-and tenfold or ment of hemodialysis patients. more, depending... more tive risk (RR) of death between two-and tenfold or ment of hemodialysis patients. more, depending on the severity of PEM and the interac-Background. Although serum prealbumin is considered a tion of PEM with other factors (age, anemia, dialysis valid indicator of nutritional status in hemodialysis patients, vintage, etc.) [1-3]. Serum albumin has been the most there is relatively little evidence that its determination is of commonly employed marker of PEM, based largely on major prognostic significance. In this study, we aimed to determine the independent association of serum prealbumin with Key words: maintenance dialysis, protein energy malnutrition, serum line on Nutrition, the validity and clinical utility of several albumin, mortality and hemodialysis, chronic renal disease, adequacy of dialysis, dietary metabolic needs.
ity in those patients who are in the lower 50th percentile for Body weight-for-height relationshi... more ity in those patients who are in the lower 50th percentile for Body weight-for-height relationships predict mortality in mainthis measurement. tenance hemodialysis patients.
not) and also with increasing body size (whether adjusted for The urea {clearance ϫ dialysis time... more not) and also with increasing body size (whether adjusted for The urea {clearance ϫ dialysis time} product (Kt) as an outcome-Kt or not) for each estimate of size. Significant statistical interbased measure of hemodialysis dose.
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