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

The rise in serum vitamin A 5 h after a 450 microgram 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 X 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 less than 30 microgram/dl and an abnormal dark adaptation test or RDR greater than or equal to 14%) were treated with 4 wk of oral vitamin A (10,000 microgram/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 less than 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.