Evaluation of the relative dose response test for vitamin A nutriture in cirrhotics

Abstract

The rise in serum vitamin A 5 h after a 450 µg oral dose of the vitamin (retinyl palmitate) was used to assess vitamin A nutriture in patients with alcoholic cirrhosis. The test was carried out on 21 hospitalized male patients and 12 normal age and sex-matched control subjects. The relative dose response (RDR), expressed as percentage, was calculated as A₅ − A₀/A₅ × 100 where A₀ = the fasting serum retinol level and A₅ = the serum retinol 5 h postdosing. Vitamin A-deficient patients (those with serum retinol levels µg/dl and an abnormal dark adaptation test or RDR ≥14%) were treated with 4 wk of oral vitamin A (10,000 µg/day), then repeat RDR and dark adaptation tests were carried out. Among eight cirrhotics with abnormal dark adaptation, the mean ± SEM RDR was 21 ± 9 versus 3 ± 3% in patients with normal dark adaptation (p < 0.01). RDR tests of patients with normal dark adaptation did not differ from those of 12 normal age and sex-matched control subjects (normal RDR response 0 to 14%). Among patients found to be vitamin A-deficient, treatment with vitamin A resulted in the mean ± SEM RDR declining from 21 ± 9 to 5 ± 2%. However, this fall failed to reach statistical significance (p = 0.06). The RDR test appears to be useful as a predictor of vitamin A deficiency, even among patients with far advanced hepatic disease.