A Drop in Hemoglobin as an Association with Pegylated Interferon Retinopathy: A Novel Pathophysiology

PURPOSE: To describe the association of change in the baseline hemoglobin levels with the development of interferon (INF) retinopathy after the start of pegylated INF (PEG INF) and ribavirin for hepatitis C virus treatment. METHODS: This was a retrospective chart review conducted on 12 patients on PEG INF and ribavirin with baseline examination and follow-up during the treatment regimen: 6 developed INF-induced retinopathy and 6 patients were without retinopathy. Serial hemoglobin values for both the groups were recorded at the time of the retinopathy diagnosis in affected patients and the nadir in those without retinopathy. The total percent reduction of hemoglobin was calculated for both the groups. RESULTS: Hemoglobin concentration levels between control and INF retinopathy patients tended to be slightly lower in the group that developed retinopathy. There was no threshold hemoglobin concentration under which the rate of developing retinopathy significantly increased. Greater than 25% drop in hemoglobin conferred a statistically significant risk in the development of INF-associated retinopathy. CONCLUSION: Patients starting PEG INF and ribavirin require baseline testing and subsequent follow-up based on the rapidity of the decrease in hemoglobin levels to identify the development of retinopathy with treatment.