Adequate protein intake may improve albumin levels in hemodialysis patients, study says.
Protein malnutrition develops in CKD patients frequently, especially those on chronic hemodialysis. In these patients, low serum albumin (less than 3.5 mg/dL) is closely linked to inflammation, which is strongly associated with morbidity and mortality.
Recent studies suggest that patient-specific interventions can improve protein nutrition in hemodialysis patients.
Janeen B. Leon, MS, RD, and her colleagues at Case Western Reserve University in Cleveland conducted a randomized, controlled trial in-volving 180 patients at 44 long-term hemodialysis facilities with baseline albumin levels less than 3.7 mg/dL (Am J Kidney Dis. 2006;48:28-36).
Study coordinators identified specific barriers to adequate nutritional intake among intervention patients, whereas control patients continued to receive usual care. Barriers targeted with correctional steps included poor nutritional knowledge, poor appetite, help needed with shopping or cooking, low fluid intake, inadequate dialysis dose, depression, difficulty chewing or swallowing, GI symptoms, and acidosis.
After 12 months, the intervention patients had greater increases in albumin levels compared with control patients (+0.21 vs. +0.06 g/dL) as well as greater increases in energy intake (+0.13 vs. -0.06 Kcal/d/kg) and protein intake (+0.13 vs. -0.06 g/d/kg).
About half the subjects had elevated levels of inflammatory markers, but there was no relationship between the change in albumin levels and inflammatory markers. “A nutrition intervention tailored to patient-specific barriers resulted in modest improvements in albumin levels regardless of levels of inflammatory markers,” the authors concluded.
Some nutritional supplements for hemodialysis patients have been designed to have anti-inflammatory and antioxidant properties. Specifically, Oxepa contains 355 cal and 14.8 g protein per 237 mL can. Its ingredients include the easily digested and absorbed maltodextrin and medium-chain triglycerides, borage oil, and fish oil.
Each can of included 1,020 mg gamma-linolenic acid, 1,080 mg eicosapentanoic acid, 2,840 IU vitamin A activity, 75 mg IU vitamin E activity and 200 mg vitamin C. Another product is Nepro, which provides 475 calories and 16.7 g protein per can in the form of high-oleic safflower oil, corn syrup solids, and fructo-oligosaccharides.
A team led by Kamyar Kalantar-Zadeh, MD, PhD, MPH, of the University of California in Los Angeles (UCLA), found that one can each of Nepro and Oxepa at each dialysis session improved serum albumin from 3.44 to 3.68 g/dL in four weeks in maintenance hemodialysis (MHD) patients (J Ren Nutr. 2005;15:318-331). Sixteen of the study’s 20 pa-tients showed improvement. Serum albumin did not change in the control group.
“In hypoalbuminemic MHD patients, a short-term, in-center nutritional intervention with one can of Nepro and one can of Oxepa during HD is practical, convenient, well-tolerated, and associated with a significant increase in serum albumin level,” the investigators concluded. Unfortunately, no data were given on the effects of the supplements on inflammatory markers, or whether response was different in patients with elevated inflammatory markers.
Several studies indicate that higher protein intakes are associated with increased survival in hemodialysis patients. Christian S. Shinaberger, MPH, and colleagues at UCLA determined protein intake and urea kinetic-based normalized protein nitrogen appearance (nPNA) in 53,933 MHD patients over a two-year period (Am J Kidney Dis. 2006;48:37-49).
Cox models were used to estimate death hazard ratios for quarterly averaged nPNA categories controlled for case mix, comorbidity, dialysis dose, and available markers of malnutrition-inflammation complex syndrome (MICS). The best survival was associated with nPNA be-tween 1.0 and 1.4 g/kd/d, whereas nPNA less than 0.8 or greater than 1.4 g/kg/d was associated with greater mortality. Adjustment for MICS mitigated the associations substantially.
“Low daily protein intake or decrease in its magnitude over time is associated with increased risk for death in MHD patients,” the authors concluded. “Whether the association between time-varying protein intake and survival is causal or a consequence of anorexia secondary to MICS or other factors needs to be explored further in interventional trials.”
Overall, these studies support the use of nutrition intervention in hemodialysis patients, even in those with MICS. Further study is needed to determine the most effective treatment for correcting low protein intake in patients with MICS, and whether anti-inflammatory ingredients are additionally beneficial.
According to guidelines developed under the National Kidney Foundation Kidney Disease Out-come Quality Initiative, protein intakes of less than 0.75 g/kg/day are inadequate for most MHD patients. A safe dietary protein intake that will maintain protein balance in almost all clinically stable MHD patients is 1.2 g protein per kilogram of body weight, with at least 50% of the protein of high biological value, the guidelines state.
The current nutritional recommendations from the National Kidney Foundation can be found at http://www.kidney.org/professionals/KDOQI/guidelines_updates/doqi_nut.html.