Objectives

Lymphocyte percentage (LYM%), an independently measured value to reflect peripheral lymphocyte count and a possible nutritional marker, may be related to clinical outcome in maintenance dialysis (MHD) patients.

Study design and setting

We examined the associations of the baseline white blood cell count (WBC) and LYM% with 12-month mortality and three measures of hospitalization in a cohort of 1,283 MHD patients from 10 outpatient DaVita dialysis clinics in Los Angeles County, as well as in a subcohort of 372 MHD patients with additional measures of inflammation, nutrition and comorbidity. Multi-variate Cox and Poisson models that included 13 co-variates including case-mix features, dialysis dose, blood hemoglobin and serum albumin were explored.

Results

Patients, aged 57.8 +/- 15.2 years, included 49% men and 49% diabetics. Baseline WBC was 7,353 +/- 2.427 per microl, and LYM% was 21.2 +/- 7.3%. LYM% had significant correlations with "malnutrition-inflammation score" and inverse correlations with serum interleukin-6. The WBC and LYM% had significant but opposite predicting values for mortality and hospitalization, indicating that a high WBC and a low LYM% were each independently associated with increased mortality. After dividing each variable into four quartiles, only the highest WBC quartile (> or = 8,500) but not the other middle two quartiles, predicted increased mortality. However, all three lower quartiles of LYM% vs. the highest quartile (based on quartile cutoffs of 16%, 20.3% and 25.5%) were significantly and progressively associated with greater risks of mortality and hospitalizations. The absolute lymphocyte count (LYM% times WBC/100) exhibited somewhat similar trends but its outcome predictability was not as strong as LYM%.

Conclusions

A high WBC and a low LYM% are associated with significant increase in mortality and hospitalization in MHD patients. Lymphocyte percentage, compared to absolute lymphocyte count, appears to be a better nutritional and anti-inflammatory marker and a more sensitive predictor of mortality and hospitalization in MHD patients.

Ketoacid (KA) analogues of essential amino acids (EAAs) provide several potential advantages for people with advanced chronic kidney disease (CKD). Because KAs lack the amino group bound to the α carbon of an amino acid, they can be converted to their respective amino acids without providing additional nitrogen. It has been well established that a diet with 0.3 to 0.4 g of protein per kilogram per day that is supplemented with KAs and EAAs reduces the generation of potentially toxic metabolic products, as well as the burden of potassium, phosphorus, and possibly sodium, while still providing calcium. These KA/EAA-supplemented very-low-protein diets (VLPDs) can maintain good nutrition, but the appropriate dose of the KA/EAA supplement has not been established. Thus, a KA/EAA dose-response study for good nutrition clearly is needed. Similarly, the composition of the KA/EAA supplement needs to be reexamined; for example, some KA/EAA preparations contain neither the EAA phenylalanine nor its analogue. Indications concerning when to inaugurate a KA/EAA-supplemented VLPD therapy also are unclear. Evidence strongly suggests that these diets can delay the need for maintenance dialysis therapy, but whether they slow the loss of glomerular filtration rate in patients with CKD is less clear, particularly in this era of more vigorous blood pressure control and use of angiotensin/aldosterone blockade. Some clinicians prescribe KA/EAA supplements for patients with CKD or treated with maintenance dialysis, but with diets that have much higher protein levels than the VLPDs in which these supplements have been studied. More research is needed to examine the effectiveness of KA/EAA supplements with higher protein intakes.

Oxidative stress and cardiovascular disease are risk factor of patients with chronic kidney disease (CKD) on maintenance hemodialysis. We used the fluorescence of low-density lipoprotein as an index of its proinflammatory potential to examine any role that high-density lipoprotein (HDL) might have in promoting this effect. The total body fat of the patients was measured by means of near-infrared interactance and their quality of life by means of SF36 questionnaires. In 189 randomly selected patients, followed for 30 months, HDL was found to be significantly anti-inflammatory but with a large standard deviation. Fully 17% of the patients had a decidedly proinflammatory index along with inferior SF36 scores. The patients were divided into 10% increments of total body fat percentages up to 40%. HDL was found to be progressively proinflammatory the higher the body fat content. Patients with a higher HDL proinflammatory index had a higher 30-month adjusted hazard ratio for death than those whose HDL were seen to be anti-inflammatory. Our findings suggest an important role of inflammatory HDL in patients with CKD leading to poor outcome.

Background and objectives: Body mass index (BMI), determined as kilograms in body weight divided by the square of the height in meters (m2), is inversely associated with mortality in patients undergoing maintenance hemodialysis (MHD). It is commonly inferred that differences in the weight component of the BMI equation are responsible for this negative correlation. However, there are almost no data on the relationship between height and mortality in these patients. This study was conducted to examine the association between height and mortality in MHD patients and to evaluate the contribution of height to the BMI-mortality relationship. Design, setting, participants, & measurements: A prospective study conducted from July 1, 2001, through June 30, 2006, enrolled a nationally representative cohort of 117,644 MHD patients receiving treatment in DaVita, Inc. outpatient dialysis facilities with (1) known height and weight, (2) age ≥18 years, (3) dialysis vintage ≥90 days, and (4) nonoutlying BMI values (≥12 to ≤60 kg/m2). The end date of follow-up was June 30, 2007, and median follow-up was 852 days (interquartile range, 504–1367 days). Mortality hazard ratios were computed within sex-standardized deciles of height and weight, and outcomes included all-cause mortality and cardiovascular, gastrointestinal, cancer, and infection mortality. Hazard models were unadjusted, adjusted for case-mix variables, or adjusted for case-mix variables plus laboratory variables. Results: Mean age was 61±15 years; 45% of patients were women and 57% had diabetes. In adjusted models, height, also adjusted for weight, was directly associated with all-cause mortality and cardiovascular, infection, and cancer mortality. Compared with the median height decile, mortality risk in the highest height decile was 1.18 (95% confidence interval, 1.14 to 1.23) in fully adjusted analyses (P<0.001). Receiver-operating characteristic curves indicated that in adjusted analyses the contribution of height to the relationship between BMI and mortality was almost identical to that of weight. Conclusions: In MHD patients, height is positively associated with mortality risk and contributes similarly to weight with regard to the negative BMI-mortality relationship.