Albumin infusion prevents renal impairment and reduces mortality among patients with spontaneous bacterial peritonitis (SBP), according to a meta-analysis published in the February issue of Clinical Gastroenterology and Hepatology.
SBP is a common bacterial infection among cirrhotic patients and a dangerous complication of ascites. Mortality can reach 30% despite antibiotic therapy.
The splanchnic vasodilation characteristic of patients with cirrhosis and ascites reduces the effective arterial blood volume, leading to activation of the renin−angiotensin−aldosterone system and sympathetic nervous system, and vasoconstriction in nonsplanchnic vascular beds, including the kidney. Increased production of cytokines and nitric oxide increase circulatory dysfunction, leading to kidney hypoperfusion.
Renal failure therefore develops in 30%−40% of patients with SBP, even after the infection is controlled.
Albumin infusion has been reported to reduce renal impairment and mortality in patients with SBP.
Francesco Salerno compared data from 4 randomized controlled trials, of 288 total patients, to quantify the effect of albumin infusion on renal impairment and mortality in patients with SBP.
They found that overall, albumin infusion in patients with SBP decreased renal impairment and reduced mortality.
The effects of albumin infusion were remarkably consistent among trials.
The pooled odds ratio for a reduction in renal impairment after albumin infusion was 0.2. Mortality among controls was 35.4%, compared with 16.0% among patients who received albumin. The pooled odds ratio for decreased mortality after infusion of albumin was 0.34.
How does albumin prevent renal failure in patients with SBP? Salerno et al. explain that albumin increases intravascular volume and cardiac preload; this improves left ventricular function and corrects the deficit in effective arterial blood volume that activates vasoconstrictor systems that contribute to renal hypoperfusion.
Albumin can also bind to and inactivate endotoxin and block lipopolysaccharide-stimulated oxidative burst activity of neutrophils. Furthermore, albumin has been reported to serve as a reservoir, traffic protein, and modulator of nitric oxide activity.
In addition to studies to determine albumin’s exact mechanisms, Salerno et al. state that further analysis is needed of the dose−response relationship between infused albumin and outcome. Patients in 3 trials of the trials assessed received albumin dosages of 0.5–1.5 g/kg−1 for at least 3 days, whereas a lower fixed dose (10 g daily for 3 days) produced good results in the fourth trial. More data are therefore needed to optimize dosing.
A trial published in 1999 reported that albumin infusion greatly reduced renal impairment and mortality. Salerno et al. explain that, based on those data, recommendations that patients with SBP receive albumin have been incorporated in clinical guidelines. However, in the current guidelines of the American Association for the Study of Liver Diseases (AASLD), the recommendation to administer albumin to patients with SBP was assigned Level of Evidence B, because it was based on a single controlled trial (Level A is reserved by the AASLD for recommendations supported by meta-analysis or multiple controlled trials).
Salerno et al. conclude that their meta-analysis provides the basis for a Level A recommendation in the AASLD guidelines that patients with SBP be treated with albumin.
In conjunction with data from retrospective studies, the meta-analysis also supports the current European Association for the Study of the Liver recommendation that all patients with SBP receive albumin.
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Salerno F, Navickis RJ, Wilkes MM. Albumin infusion improves outcomes of patients with spontaneous bacterial peritonitis: a meta-analysis of randomized trials. Clin Gastroenterol Hepatol 2013;11:123-130.e1.