Levin_subbed.qxp 5/2/09 2:15 pm Page 54
Dialysis
Improvement of Albumin Control in Hemodialysis Patients—What Is Possible?
a report by
Murat H Sipahioglu, MD
1
and Nathan W Levin, MD, FACP
2
1. Research Fellow, Renal Research Institute; 2. Medical and Research Director, Renal Research Institute,
Professor of Clinical Medicine, Albert Einstein College of Medicine, and Attending Physician, Beth Israel Medical Center
Despite improvements in dialysis technology and an increase in the hypoalbuminic patients. In general, albumin synthesis is increased in
proportion of patients receiving adequate hemodialysis (HD) by guideline dialysis patients with normal nutritional status compared with healthy
standards, hypoalbuminemia is a common problem in dialysis patients. people;
7
however, hypoalbuminemic dialysis patients have reduced
Lower serum albumin is a powerful predictor of morbidity and mortality in albumin synthesis.
8
In a study on 59 HD patients, Kaysen et al.
6
reported
this population.
1,2
Albumin is a single polypeptide of 585 amino acids with that a decrease in serum albumin of >0.3g/dl that persists for a period of
a molecular weight of 69kDa. It is negatively charged at physiological pH. six weeks is associated with a decrease in albumin synthesis. In that
Its synthesis is performed in the liver, with albumin accounting for almost study, the levels of acute-phase proteins were also significantly increased
50% of total liver protein synthesis.
3
The half-life of albumin is 16–21 days. in those with the lower albumin concentration.
Forty percent of body albumin is in the intravascular space, with the
remainder in the interstitial space. Albumin is catabolized in endothelial Epidemiological studies have consistently shown a strong association
cells. Hypoalbuminemia occurs in dialysis patients because of a decrease in between malnutrition and inflammation in dialysis patients.
9
The term
its synthesis and external losses (e.g. with overbleached dialyzers in HD malnutrition–inflammation complex syndrome (MICS) is used to indicate the
patients and across the peritoneal membrane in peritoneal dialysis [PD] combination of malnutrition and inflammation in dialysis patients.
10
patients). Routine albumin measurements are made pre-dialysis in HD Malnutrition with inflammation reduced albumin synthesis.
11,12
Since MICS is
patients, and these analyses may show misleading low albumin common in dialysis patients,
13
it may be the leading cause of low serum
concentrations because of dilution of plasma by extracellular volume albumin in these patients. It is not obvious which of these two factors has
expansion during the interdialytic period.
4
a greater effect on serum albumin concentrations.
14
While hypoalbuminemia cannot be attributed to a single factor, Depending on the method used to determine nutritional status, the
decreased albumin synthesis plays a major role.
5
Albumin catabolic rate frequency of malnutrition in HD patients is reported to vary from 20 to
was not increased in hypoalbuminemic HD patients compared with 70%.
15
When urea kinetic modeling is used, the routine measurement of
normoalbuminemic HD patients.
5
Kaysen et al.
6
showed that there was protein catabolic rate (PCR) provides an insight into nutritional intake. The
no stable shift of albumin from the vascular to the extravascular pool in main reasons for malnutrition are loss of appetite (due to the effects of
uremic toxins, pro-inflammatory cytokines, and leptin), medications that can
impair nutrient absorption, inadequate dialysis dose and gastroparesis (by
Murat H Sipahioglu, MD, is an Assistant Professor in the
Nephrology Department at Erciyes University Medical School in
slowing gastric emptying due to autonomic neuropathy), and dietary
Kayseri, Turkey, and a Research Fellow at the Renal Research restriction. Serum albumin concentration may decrease slightly with
Institute in New York under the supervision of Dr Nathan W Levin.
development of malnutrition. However, malnutrition alone has very little
Dr Sipahioglu is a member of the European Renal Association–
European Dialysis and Transplant Association (ERA-EDTA) and the
effect on plasma albumin level, as evidenced by the fact that anorexia
Turkish Society of Nephrology. He attended medical school at the nervosa patients do not show hypoalbuminemia until the terminal period of
University of Erciyes in Kayseri and performed his residency at
disease.
16
Inflammation is a physiological response mounted against both
Cerrahpasa Medical Faculty in Istanbul and Erciyes University
Medical Faculty in Kayseri. He completed an observership program under Dr Juan P Bosch in the
the injurious agent and injured tissues. A chronic inflammatory process is
Department of Nephrology at George Washington University in Washington, DC in 2000. common in end-stage renal disease (ESRD) patients and may be a major
factor determining outcomes.
Nathan W Levin, MD, FACP, is a Professor of Clinical Medicine at
Albert Einstein College of Medicine and an Attending Physician in There are many potential reasons for inflammation in dialysis patients:
the Division of Nephrology and Hypertension at Beth Israel
Medical Center in New York. He also serves as Medical and
Research Director at the Renal Research Institute. He is involved in
• encounter between blood and dialyzer surface, especially cuprophane
many professional societies, including the International Society of and regenerated cellulose dialyzers—the use of such membranes is rare
Nephrology (ISN) and KDIGO. Dr Levin has received numerous
in the US;
awards and recognitions, including the American Association of
Kidney Patients (AAKP) Medal of Excellence. He has published
• dialysate contaminated with endotoxin—endotoxin contamination of
over 350 articles on areas of nephrology. water for dialysis and dialysate is derived primarily from biofilm coating
E:
nlevin@rriny.com
the internal surfaces of water and concentrate loops and tanks
(predominately bicarbonate);
54 © TOUCH BRIEFINGS 2008
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84