Relationship of Normalized Protein Catabolic Rate with Nutrition Status and Long-Term Survival in Peritoneal Dialysis Patients.

The normalized protein catabolic rate (nPCR) reflects daily dietary protein intake in stable dialysis patients. In peritoneal dialysis (PD) patients, reports about the importance of nPCR as marker of nutrition and outcome have been inconsistent. The objective of the present study was to investigate the relationships of nPCR with body composition parameters, micronutrient electrolytes, and long-term survival in PD patients. From November 2000 to May 2008, 57 PD patients were enrolled in the study. On enrollment, demographic, clinical, and biochemical data were recorded. Patients were followed through September 2011. Mean age of the patients was 56 years, and 61% were of African descent. Mean and maximum follow-up were 2.83 years and 11 years respectively. Mean daily nPCR was 0.944 g/kg. The nPCR correlated directly with albumin (r = 0.34, p = 0.012), magnesium (r = 0.48, p < 0.0001), phosphorus (r = 0.42, p = 0.02), and the phase angle body composition parameter (r = 0.26, p = 0.049). Compared with patients whose enrollment daily nPCR was less than 0.8 g/kg, those with an enrollment daily nPCR of 0.8 g/kg or more experienced significantly better 11-year cumulative survival (p = 0.04). In multivariate Cox regression analysis with adjustment for confounding variables, nPCR was an independent predictor of all-cause mortality (p = 0.018). In conclusion, lower nPCR is associated with poorer nutrition status and increased risk of all-cause mortality in PD patients followed for up to 11 years.

Relationship between alkaline phosphatase and all-cause mortality in peritoneal dialysis patients.

Elevated levels of serum alkaline phosphatase (AlkPhos) have been reported to be associated with increased mortality risk in hemodialysis (HD) patients. We examined the association of serum AlkPhos with all-cause mortality in our PD patients. The study enrolled 90 PD patients beginning in 1995. On enrollment, demographics and clinical and biochemical data were recorded. Patients were followed to September 2011. Mean age of the enrollees was 52 years, with 61% being women, and most (81%) being of African descent. Mean and median AlkPhos were 135 U/L and 113 U/L respectively. Mean and maximum follow-up were 2.61 and 16 years respectively. As expected, AlkPhos correlated directly with serum intact parathyroid hormone (r = 0.36, p = 0.003). In a Cox multivariate regression analysis with adjustment for confounding variables, AlkPhos as a continuous (relative risk: 1.016; p = 0.004) anda categorical variable [> 120 U/L and < or = 120 U/L (relative risk: 6.0; p = 0.03)] remained a significant independent predictor of mortality. For each unit increase in enrollment AlkPhos, there was a 1.6% increase in the relative risk of death. Elevated serum AlkPhos is significantly and independently associated with increased mortality risk in our PD patients followed for up to 16 years. AlkPhos should be evaluated prospectively as a potential therapeutic target in clinical practice.

Dialysis vintage, body composition, and survival in peritoneal dialysis patients.

The relationship between dialysis vintage (length of time on dialysis), body composition, and survival has been reported in hemodialysis patients. In the present study, we examined the association ofdialysis vintage with body composition and survival in peritoneal dialysis (PD) patients. At enrollment, body composition in 65 PD patients was determined by bioelectrical impedance analysis. Patients (mean age at enrollment: 54 years) were followed for up to 11 years maximum. At enrollment, the mean, median, and maximum dialysis vintages were 51, 34, and 261 months respectively. After adjusting for age, race, sex, and diabetes status, dialysis vintage was indirectly correlated (partial correlation coefficients) with body weight (r = -0.40, p = 0.001), body mass index (r = -0.40, p = 0.002), body surface area (r = -0.39, p = 0.002), body cell mass (r = -0.39, p = 0.002), total body fat weight (r = -0.30, p = 0.02), and fat percentage of body weight (r = -0.31, p = 0.018), and directly correlated with extracellular mass to body cell mass ratio (r = 0.27, p = 0.039). The observed cumulative survival was significantly higher (p = 0.007) in patients with a dialysis vintage at enrollment of 35 months or less, than in patients with dialysis vintage at enrollment of more than 35 months. In the multivariate Cox regression analysis, adjusting for age, race, sex, and diabetes, dialysis vintage at enrollment remained an independent predictor of mortality (relative risk: 1.010; p = 0.002). Increase in relative risk of death with increasing dialysis vintage may be partly explained by the association of vintage with unfavorable changes in body composition and the nutrition status of patients over time.

Extracellular mass/body cell mass ratio is an independent predictor of survival in peritoneal dialysis patients.

Malnutrition is a strong predictor of mortality in peritoneal dialysis (PD) patients. Extracellular mass (ECM) contains all the metabolically inactive, whereas body cell mass (BCM) contains all the metabolically active, tissues of the body. ECM/BCM ratio is a highly sensitive index of malnutrition. The objective of this study was to explore the relationship between ECM/BCM ratio and survival in PD patients. We enrolled 62 patients from November 2000 to July 2008. On enrollment, demographic, clinical, and biochemical data were recorded. Bioimpedance analysis (BIA) was used to determine ECM and BCM in PD patients. Patients were followed up to November 2008. Mean age was 54+/-16 (s.d.) years; female, 55%; African Americans, 65%; diabetic, 24%. Mean ECM/BCM ratio was 1.206+/-0.197 (range: 0.73-1.62). Diabetics had higher ECM/BCM ratio than nondiabetics (1.29 vs 1.18, P=0.04). ECM/BCM ratio correlated directly with age (r=0.38, P=0.002) and inversely with serum albumin (r=-0.43, P=0.001), creatinine (-0.24, P=0.08), blood urea nitrogen (r=-0.26, P=0.06), and total protein (r=-0.31, P=0.026). Using multivariate Cox regression analysis, adjusting for age, race, gender, diabetes, and human immunodeficiency virus status, enrollment ECM/BCM ratio was a significant independent predictor of mortality (relative risk=1.035, P=0.018). For every 10% increase in the ECM/BCM ratio, the relative risk of death was increased by about 35%. In conclusion, BIA-derived enrollment ECM/BCM ratio, a marker of malnutrition, was an independent predictor of long-term survival in PD patients.

Pulmonary hypertension in peritoneal dialysis patients.

The information available in the literature regarding pulmonary hypertension (PH) in peritoneal dialysis (PD) patients is limited. The objective of the present study was to examine the prevalence and characteristics of PH in PD patients. We retrospectively collected the clinical profile, echocardiographic (ECHO) findings, and biochemical data for 36 PD patients for which ECHO findings were available. We compared characteristics between patients with and without PH. We found PH, defined as pulmonary arterial pressure (PAP) > or = 35 mmHg, in 15 patients. The prevalence of PH was 42%. Mean age (+/- standard deviation) of the patients with and without PH was 58 +/- 15 years and 52 +/- 15 years respectively (p = 0.30). Mean PAP of the PH patients was 43.8 +/- 9.0 mmHg (range: 35-65 mmHg). Patients with PH had a lower ejection fraction than did patients without PH (46.3% +/- 19.8% vs. 56.5% +/- 11.8% respectively, p = 0.07). Patients with PH also had a higher prevalence of global hypokinesia (60% vs. 29%, p = 0. 059) and dilated left ventricular chamber (53% vs. 19%, p = 0.03). In PH patients, body mass index (24 +/- 4.5 kg/m2 vs. 28 +/- 5.0 kg/m2, p = 0.024), normalized protein catabolic rate (0. 78 +/- 0.21 g/kg vs. 0.95 +/- 0.27 g/kg daily, p = 0.049), and ferritin (226 +/- 210 ng/mL vs. 873 +/- 965 ng/mL, p = 0.005) were significantly lower and lactate dehydrogenase was higher (264 +/- 99 U/L vs. 206 +/- 79 U/L, p = 0.06) than in patients without PH. We observed no significant differences in race or sex, incidence of hypertension or cardiovascular disease, or vitamin D analog use between the two groups of patients. During the study period, 60% of PH patients and 38% of patients without PH died (p = 0.19). Values of PAP correlated directly with serum levels of phosphorus (r = 0.44, p = 0.02), CaxP product (r = 0.40, p = 0.04), and parathyroid hormone (r = 0.42, p = 0.03). Of continuous ambulatory PD and continuous cycling PD patients, 21% and 55% respectively had PH (p = 0. 049). In PD patients, PH is highly prevalent and may be associated with higher mortality risk.

Relationship of peritoneal transport rate and dialysis adequacy with inflammation in peritoneal dialysis patients.

Inflammation, dialysis adequacy, and peritoneal transport rate (PTR) influence clinical outcomes in peritoneal dialysis (PD) patients. The present study examined the relationship of C-reactive protein (CRP), a marker of inflammation, to PTR and residual renal function (RRF) in PD patients. We recorded the baseline dialysate-to-plasma creatinine (D/P Cr) of 210 PD patients starting in 1986. In a subgroup of 42 patients, we serially measured high-sensitivity CRP levels and.dialysis adequacy, including weekly Kt/V urea and creatinine clearance (CCr), starting in May 2003. The patients were followed to January 2006. Mean age was 53 +/- 16 (standard deviation) years, and 70% of the patients were African American. Enrollment mean and median CRP levels were 13.53 +/- 20.8 (range: 0.2-95.8) and 7.15 mg/L respectively. Mean weekly residual CCr and Kt/V during follow-up were 7.11 +/- 15.47 L/1.73 m2 and 0.14 +/- 0.30 respectively. The mean enrollment D/P Cr was 0.649 +/- 0.12 (range: 0.429-0.954). Patients with CRP > 10 mg/L had significantly lower weekly residual CCr (0.59 L/1.73 m2 vs. 10.1 L/1.73 m2, p = 0.01), residual Kt/V (0.01 vs. 0.20, p = 0.01), total CCr (56 L/1.73 m2 vs. 62 L/1.73 m2, p= 0.047), and total Kt/V (2.09 vs. 2.49, p = 0.001) than did those with CRP < or = 10 mg/L. Levels of CRP correlated negatively with weekly residual CCr (r = -0.42, p = 0.006), residual Kt/V (r = -0.43, p = 0.006), and total Kt/V (r = -0.44, p = 0.004). Enrollment D/P Cr was inversely correlated with serum albumin (r = -0.24, p = 0.001) and directly correlated with peritoneal protein loss (r = 0.34, p = 0.028). Higher enrollment D/P Cr was associated with lower observed cumulative survival (Kaplan-Meier) in PD patients. However D/P Cr was not an independent predictor of long-term survival in PD patients. Using multivariate Cox regression analysis, and including D/P Cr and residual Kt/V in the model, enrollment CRP was an independent predictor of mortality (relative risk = 1.036, p = 0.018). We conclude that elevated CRP is associated with lower RRF As a predictor of mortality, CRP may be better than RRF and D/P Cr.

Association between C-reactive protein and clinical outcomes in peritoneal dialysis patients.

An elevated level of C-reactive protein (CRP), which is a marker of inflammation, is a risk factor for morbidity and mortality in the general population and in dialysis patients. Recently, the relationship between inflammation and nutrition status has received much attention. Serum prealbumin is a highly sensitive marker of nutrition and survival in dialysis patients. The objective of the present study was to evaluate the prognostic value and clinical correlates of CRP in peritoneal dialysis (PD) patients. Using retrospective chart review, we collected demographic, clinical, and laboratory data on 66 PD patients for the period June 2001 to January 2005. High-sensitivity CRP (hs-CRP) levels were measured in a subgroup of 32 patients starting in May 2003. Over the study period, prealbumin and CRP were assayed serially by the immunoturbidimetric method. Mean age (+/- standard deviation) of the patients was 55 +/- 15 years, and 73% were African American. Mean and median enrollment CRP were 15.2 +/- 24 mg/L (range: 4.2 - 149.5 mg/L) and 6.45 mg/L respectively. Mean and median enrollment hs-CRP were 15.3 +/- 23.5 mg/L (range: 0.2 - 96 mg/L) and 6.55 mg/L respectively. Enrollment CRP was elevated (215 mg/L) in 29% of the patients, and hs-CRP was elevated (> or = mg/L) in 63% of the patients. Enrollment CRP was strongly correlated with hs-CRP (r = 0.7, p < 0.0001). The presence of diabetes (22 mg/L vs. 7.8 mg/L, p = 0.02), infection and inflammatory conditions (44.9 mg/L vs. 11.6 mg/L, p = 0.001), and lower levels of markers of nutrition such as prealbumin (r = -0.47, p < 0.0001) and creatinine (r = 0.35, p = 0.006) were associated with a higher level of CRP. Enrollment hs-CRP was a significant predictor of mortality in PD patients (relative risk = 1.044, p = 0.023). The observed cumulative survival (Kaplan-Meier) of patients with hs-CRP <15 mg/L was significantly better (p = 0.007) than was the survival of patients with a hs-CRP > or =15 mg/L. In a multivariate regression analysis, serum prealbumin was the best and only significant predictor of CRP level (beta = -0.37, p = 0.005). Elevated CRP was associated with infection and inflammation. Therefore, routine testing of hs-CRP in PD patients should be considered.

Survival experience of peritoneal dialysis patients with human immunodeficiency virus: a 17-year retrospective study.

Human immunodeficiency virus (HIV)-related renal disease is the third-leading cause of end-stage renal disease (ESRD) among African Americans aged 20-64 years. The number of HIV-infected (HIV+) patients reaching ESRD will increase exponentially over the next decade. Because of significant improvements in therapy and management during the last ten years, survival of HIV+ patients has improved. The survival experience of very long-term HIV+ peritoneal dialysis (PD) patients remains to be investigated. The objective of the present study was to examine the important differences in clinical and laboratory parameters between HIV+ and HIV-negative (HIV-) PD patients. To assess the factors associated with better survival in HIV+ PD patients, we retrospectively reviewed the charts of 488 PD patients, including 53 HIV+ patients, for the period 1987 to September 2004. We collected demographic, clinical, and laboratory data, including CD4 cell counts and history of hospitalizations and peritonitis. Maximum survival of HIV+ PD patients was 12.5 years as compared with 15.87 years in HIV-patients. Not surprisingly, HIV was a strong independent predictor of mortality in PD patients [relative risk (RR) = 3.09, p < 0.0001]. In HIV+ patients, higher CD4 counts at the initiation of dialysis were strongly associated with better survival (RR = 0.10 and p < 0.0001, > or =200 cells/mm3 vs. < or =50 cells/mm3). In univariate analysis, use of highly active antiretroviral therapy (HAART) was associated with significantly improved survival in HIV+ PD patients. Patients treated with I or 2 drugs had a 4.3-times higher mortality risk than those who received HAART therapy (p = 0.012). Independent associations were seen between HIV and younger age, African American race, male sex, and lower serum albumin. The rates of hospitalization (p < 0.0001) and peritonitis (p < 0.01) were significantly higher in HIV+ patients than in HIV-patients. Very long-term survival of HIV+ patients with chronic renal failure is possible on PD therapy. Morbidity and mortality of these patients may be improved with HAART therapy, better nutrition, and treatment of peritonitis.

Hemoglobin predicts long-term survival in dialysis patients: a 15-year single-center longitudinal study and a correlation trend between prealbumin and hemoglobin.

BACKGROUND: Dialysis patients have much higher mortality rates than the general population. Anemia is a common complication of uremia and a major contributor to morbidity and mortality in dialysis patients. The benefits of anemia correction using recombinant human erythropoietin (rHuEPO) are well established. Optimum hemoglobin level for dialysis patients remain controversial. We have investigated the association of enrollment hemoglobin with long-term survival in hemodialysis (HD) and peritoneal dialysis (PD) patients. METHODS: We enrolled 529 HD and 326 PD patients from 1987 and followed them to April 2003. Demographics, enrollment, and clinical and laboratory data were recorded. The Kaplan-Meier method was used to compute observed survival, and the multivariate Cox regression analysis was used to identify the independent predictors of mortality risk. RESULTS: Mean ages of HD and PD patients were 60 +/- 16 (SD) and 54 +/- 16 (SD) years, respectively. Forty-seven percent of HD patients and 41% of PD patients were diabetic. Mean enrollment hemoglobin levels of HD and PD patients were 9.44 +/- 1.9 and 9.61 +/- 1.77 g/dL respectively. Cumulative 15 year observed survivals of HD (P = 0.05) and PD (P = 0.032) patients with hemoglobin levels greater or equal to 12 g/dL were higher than those with hemoglobin levels less than 12 g/dL. Hemoglobin <12 g/dL was a better predictor of mortality in nondiabetics than diabetics, particularly in HD patients. Both in HD and PD diabetic patients, hemoglobin was not a significant predictor of mortality. By Cox regression analysis, after adjusting for age, race, gender, and months on dialysis at enrollment, the relative risk of mortality of patients with hemoglobin <12 g/dL was 2.13-fold (P = 0.008) higher for HD and 1.85-fold (P = 0.06) higher for PD compared to those with hemoglobin >/=12 g/dL (P = 0.035). A logistic regression analysis revealed a strong inverse relationship between the hemoglobin level and the odds risk of death in HD (OR = 0.83, P = 0.008) and in PD (OR = 0.85, P = 0.02) patients. CONCLUSION: Enrollment hemoglobin is a predictor of long-term survival in HD and PD patients. Patients with hemoglobin levels that are higher than current treatment recommendations (>12 g/dL) may benefit from long-term survival. Survival of dialysis patients may be improved by better management of malnutrition and anemia.

Relationship of bioelectrical impedance parameters to nutrition and survival in peritoneal dialysis patients.

BACKGROUND: Malnutrition is highly prevalent in peritoneal dialysis (PD) patients and is associated with higher mortality in these patients. In this study, we have prospectively examined the relationship of bioimpedance indexes to the nutritional status and survival in PD patients. METHODS: We enrolled 48 PD patients beginning in November 2000. On enrollment, bioelectrical impedance analysis (BIA) (BIA-101; RJL/Akern, Clinton Township, MI, USA) was performed and monthly blood was analyzed for biochemical markers, including prealbumin. Patients were followed until April 2003. RESULTS: The mean age of PD patients was 51 +/- 15 (SD) years. Fifty-eight percent of the patients were female and 23% of the patients were diabetic. Mean body mass index (BMI) was 25.7 +/- 5.0 kg/m2. Mean resistance, reactance, and phase angle were 521 +/- 104 ohms, 57 +/- 19 ohms, and 6.16 +/- 1.6 degrees, respectively. During the study period, 8 patients (17%) expired. The Kaplan-Meier method was used to compute observed survival. The cumulative observed survival of PD patients with enrollment phase angle greater than or equal to 6 degrees was significantly higher (P = 0.008) than that of patients with phase angle less than 6. Using Cox's multivariate regression analysis, phase angle was an independent predictor (relative risk = 0.39, P = 0.027) of more than two years' survival in PD patients. Serum prealbumin was directly correlated with phase angle (r = 0.54, P < 0.0001), reactance (r = 0.55, P < 0.0001), and resistance (r = 0.29, P = 0.06). CONCLUSION: BIA indexes reflect nutritional status and may be useful in monitoring nutritional status in PD patients. Phase angle is a strong prognostic index in PD patients. It is useful to incorporate prealbumin and BIA parameters in the regular assessment of PD patients, whose survival may be improved by better management of malnutrition and overall health status.

Malnutrition and inflammation in peritoneal dialysis patients.

BACKGROUND: Malnutrition, cardiovascular disease, and heightened inflammation are highly prevalent in dialysis patients, and major contributors to morbidity and mortality. We have investigated the inter-relationship between malnutrition and inflammation, and their impact on morbidity and mortality in peritoneal dialysis (PD) patients. METHOD: We enrolled 63 PD patients beginning in November 2000, and measured C-reactive protein (CRP) and various nutritional markers, including prealbumin. RESULTS: CRP level was elevated in 29% of the PD patients. Diabetics had higher CRP than non-diabetics (24 vs. 9.3 mg/L, P = 0.016). Patients who were hospitalized during the study had higher enrollment CRP (16 vs. 12.5 mg/L, P = 0.05) and lower enrollment albumin (3.5 vs. 3.9 g/dL, P = 0.002), blood urea nitrogen (BUN) (40 vs. 49 mg/dL, P = 0.034), and protein catabolic rate (nPCR) (0.88 vs. 1.0 g/kg/day, P = 0.02) than those who were not hospitalized. Enrollment level of CRP was inversely correlated with nutritional markers prealbumin (r = -0.5, P < 0.0001) and creatinine (r =-0.35, P < 0.01). After adjusting for age, race, gender, diabetes, and CRP level, prealbumin continued to correlate with other nutritional markers. There was a trend toward association of elevated CRP with all-cause mortality in PD patients. CONCLUSION: It is useful to incorporate prealbumin and CRP in the regular assessment of PD patients, whose survival may be improved by better management of malnutrition and inflammation.

Usefulness of bioelectrical impedance analysis in monitoring nutrition status and survival of peritoneal dialysis patients.

Malnutrition is highly prevalent in peritoneal dialysis (PD) patients and is associated with higher mortality. Lower serum levels of markers of nutrition--such as albumin, creatinine, prealbumin, and total cholesterol--are important risk factors in PD patients. Usefulness of bioimpedance analysis (BIA) in hemodialysis (HD) patients has been reported. In the present study, we prospectively examined the relationship of bioimpedance indexes to the nutrition status and survival of 45 PD patients who were followed for more than 1 year. On patient enrollment, a BIA was performed (Bioelectrical Impedance Analyzer, Model BIA-101: RJL Systems, Clinton Township, MI, U.S.A.). Monthly blood was analyzed for biochemical markers. The mean age of the study group was 50 +/- 15 years. Of the 45 patients, 56% were female and 24% were diabetic. Mean body mass index was 25.7 +/- 5.1. Mean resistance, reactance, capacitance, and phase angle were 524 +/- 106 omega 57 +/- 20 omega, 678 +/- 223 pF, and 6.2 +/- 1.7 degrees respectively. Patients with diabetes had lower capacitance (555 pF vs. 713 pF, p = 0.007) and phase angle (5.35 degrees vs. 6.4 degrees, p = 0.05) than patients without diabetes. During the study period, 4 patients died. Patients who survived had higher capacitance (486 +/- 163 pF vs. 697 +/- 218 pF, p = 0.07) and phase angle (4.65 +/- 0.73 degrees, vs. 6.34 +/- 1.67 degrees, p = 0.008) than those who did not survive. The Kaplan-Meier method was used to compute observed survival. The cumulative observed survival of PD patients with an enrollment phase angle > or = 6 degrees was significantly (p = 0.01) higher than that of patients with an enrollment phase angle < 6 degrees. Reactance was directly correlated with albumin (r = 0.52, p < 0.0001) and total protein (r = 0.44, p < 0.05). Capacitance was directly correlated with body mass index (r = 0.35, p < 0.05), albumin (r = 0.32, p < 0.05), and blood urea nitrogen (BUN) (r = 0.44, p < 0.01), and inversely correlated with body weight (r = -0.51, p < 0.0001). Phase angle was directly correlated with all of the biochemical markers of nutrition, such as albumin (r = 0.54, p < 0.01), total protein (r = 0.38, p < 0.05), creatinine (r = 0.28, p < 0.01), and BUN (r = 0.39, p < 0.05). By stepwise multivariate regression analysis, body weight (beta = -0.60, p < 0.0001) and total protein (beta = 0.32, p = 0.012) were significant determinants of resistance. Body weight (beta = -0.31, p = 0.02) and albumin (beta = 0.59, p < 0.0001) were significant predictors of reactance. Serum albumin (beta = 0.53, p < 0.0001) was the only best predictor of phase angle in PD patients. The BIA indices reflect nutrition status in PD patients, and may be useful in monitoring nutrition interventions.