Responsiveness of RDR Test to Assess Hepatic Vitamin A Stores in Chronic Liver Disease

The relative-dose-response test (RDR) is considered to be the most accurate method for evaluating vitamin A nutritional status (VANS) in patients suffering from liver disease, as it infers the reserves of the vitamin in the liver. However, for the RDR test to reflect VANS in patients suffering from chronic liver disease, factors inherent to the disease need to be considered, such as possible malabsorption, advanced age, a drop in synthesis and/or the release of retinol binding protein (RBP), which would result in an inadequate response to the RDR test. Thus, the objective of present study is to assess the adequacy of two different protocol for using the RDR test in patients with cirrhosis and cirrhosis-related hepatocellular carcinoma.

Methods: The sample group was comprised of 178 patients at Federal University of Rio de Janeiro University Hospital (111 men) with several etiologies of liver cirrhosis at different stages in the progression of the disease. They were sorted into two groups, according to the retinyl palmitate dosage (1500 IU or 2500 IU) received at T0 (blood sample taken following a 12-hour fast). Following supplementation, the investigators took further blood samples five and seven hours later (T5 and T7). The investigators assessed VANS via concentrations of serum retinol and RBP, as well as by way of the RDR test. The cutoff points the investigators used for denoting inadequacy in the indicators retinol and RDR were, respectively, < 1.05 µmol/L and ≥ 20%. To classify the degrees of severity of the disease the investigators used the criteria established by Child & Pugh (1973).