Does ascorbic acid prevent retinopathy during interferon therapy in patients with chronic hepatitis C?

Purpose. Ascorbic acid was administered to patients with chronic hepatitis C to elucidate the mechanism of onset of retinopathy during interferon (IFN) therapy, and its prevention. Methods. The subjects were 62 patients with chronic hepatitis C who had been admitted to our hospital. For the IFN therapy, 6 MIU of natural IFN-alpha or 10 MIU of recombinant human IFN-alpha 2b was administered every day for the first 2 weeks, followed by administration three times a week for 22 weeks. The patients were randomly assigned to a group receiving 600 mg/day of ascorbic acid or a group not receiving ascorbic acid (control group). The optic fundi were examined by ophthalmologists before the IFN therapy began and subsequently at weeks 2 and 4 and then every 4 weeks during the IFN therapy. Results. Retinopathy was found in 9 of the 31 patients (29%) in the ascorbic acid-treated group and in 11 of the 31 patients (35%) in the control group. The cumulative incidence of hemorrhage in the ascorbic acid-treated group was lower than that in the control group during the IFN therapy, but the difference between the two groups was not significant (P = 0.186). The cumulative incidence of cotton-wool spots in the ascorbic acid-treated group was almost same as that in the control group during the II;IFN therapy. The median platelet counts before the therapy was begun were 11.8 X 10(4)/mm(2) in the group with hemorrhage and 16.6 X 10(4)/mm(2) in the group without, and the lowest platelet counts during IFN therapy were 7.3 x 10(4)/mm(3) in the group with hemorrhage and 9.5 x 10(4)/mm(3) in the group without, indicating significantly lower values in the group with hemorrhage (P = 0.018 and P = 0.020, respectively). The lowest platelet counts during IFN therapy were 7.4 x 10(3)/mm(3) in the group with cotton-wool spots and 9.7 x 10(4)/mm(3) in the group without, indicating a significantly lower value in the group with cotton-wool spots (P = 0.036). Conclusions. Ascorbic acid was not considered to be useful for the prevention of the retinopathy associated with IFN therapy in patients with chronic hepatitis C.