Nutritional Markers during Peritoneal Dialysis: Data from the 1998 Peritoneal Dialysis Core Indicators Study

Abstract

Objective This analysis explores the nutritional status of adult U.S. peritoneal dialysis (PD) patients. Design The Peritoneal Dialysis Core Indicators Study is a prospective cross-sectional prevalence survey describing the care provided to a random sample of adult U.S. PD patients. Methods and Population Prevalence data were collected from a national random sample of 1381 adult PD patients participating in the United States End Stage Renal Disease (ESRD) program. Results The median age of these patients was 55 years, 61% were Caucasian; the leading cause of ESRD was diabetes mellitus. Age, sex, size, peritoneal permeability, dialysis adequacy, and nutritional indices did not differ between patients on continuous ambulatory PD and patients on automated PD. The dialysis prescriptions employed achieved mean weekly Kt/V urea (wKt/V) and creatinine clearance (wCCr) values of 2.22 ± 0.57 and 67.8 ± 22.5 L/1.73 m2/week, respectively. The PD patients were large, with a mean body weight of 77 ± 21 kg and body mass index (BMI) of 27 ± 8.6 kg/m2. The mean serum albumin of these patients was 3.5 ± 0.51 g/dL, and 43% of values fell below the National Kidney Foundation Dialysis Outcomes Quality Initiative's desired range. The PD patients had a normalized protein equivalent of nitrogen appearance (nPNA) of 1.0 ± 0.57 g/kg/day, a normalized creatinine appearance rate (nCAR) of 17 ± 7.3 mg/kg/day, and an estimated lean body mass (%LBM) of 62% ± 18% of body weight. Serum albumin correlated positively with patient size, nCAR, and nPNA, but negatively with age, the presence of diabetes mellitus, female gender, erythropoietin dose, the creatinine dialysate-to-plasma ratio results of peritoneal equilibration testing, and the dialysis portion of the wCCr. The duration of ESRD experience correlated negatively with both serum albumin and patient size, although these relationships were complex. Conclusion Peritoneal dialysis patients generally have marginal serum albumin levels, a finding incongruent with alternative measures of nutritional status, such as weight, BMI, and creatinine generation. Serum albumin is reduced in patients with high peritoneal permeability ( i.e., rapid transporters) and, because these patients generally have higher than average wCCr values, serum albumin is inversely correlated with the dialysis component of the wCCr. The presumptive nutritional indicators (BMI, %LBM, nPNA, and serum albumin) provide disparate estimates, varying from 10% to 50% for the prevalence of nutritionally stressed PD patients.

Malnutrition–Inflammation–Atherosclerosis (MIA) Syndrome Components in Hemodialysis and Peritoneal Dialysis Patients

“…Also, all of these parameters are the predictors of outcomes in this population. [1][2][3][4][5] Since the first report about association between elevated C-reactive protein (CRP) [6] and increased mortality, several groups have reported similar findings in both hemodialysis (HD) [7,8] and peritoneal dialysis (PD) patients alike. [9,10] Inflammation has been associated with malnutrition and atherosclerosis, and this link has led to describe MIA syndrome (Malnutrition-Inflammation-Atherosclerosis).…”

High rates of protein intake are associated with an accelerated rate of decline of residual kidney function in incident peritoneal dialysis patients

“…Some guidelines consider compelling this correction only when the current dry weight is markedly lower (<90%) or higher (>115%) than ideal weight [1,21]. This caution, neglected in some former studies, is very relevant, because normalization of PI to current body weight in undernourished, overweight or overhydrated individuals results in unrealistic estimations [12]. The advantages and drawbacks of different methods of standardization of PI have been reviewed in detail elsewhere [31].…”

“…However, the latter view has been challenged during the last two decades, for at least two reasons. First, a variable proportion of dialysis patients maintain relatively high rates of PI, often exceeding current recommendations [12,13]. The balance between the benefits and disadvantages of 'protein indulgence' in this setting is largely undetermined.…”

Hypoalbuminemia is Also a Marker of Fluid Excess Determined by Bioelectrical Impedance Parameters in Dialysis Patients

“…Our study establishes that hypoalbuminemia is related in part to a state of fluid excess in patients on dialysis. Patients on peritoneal dialysis tend to have a lower serum albumin concentration than patients on hemodialysis (22). This could be caused by, for example, a higher degree of proteinuria (related to better preservation of residual renal function), inadequate protein intake, increased peritoneal protein loses or high peritoneal transport rate with the subsequent risk of fluid overload.…”