Risks Associated with Pegylated Interferon plus Ribavirin Treatment for Hepatitis C

Treatment with pegylated interferon plus ribavirin (PegIFN/RBV) significantly increased the risk of retinal hemorrhage in people with hepatitis C virus (HCV), according to a paper published in Viruses, while the risk for retinal vascular occlusions was not increased in this population.

Investigators from Taiwan identified 1688 patients with hepatitis C that were undergoing therapy with PegIFN/RBV in order to compare them to a cohort of 3376 patients with hepatitis C that were not receiving treatment. The investigators also included 16,880 controls without hepatitis C in their analysis, which were collected from the Taiwan Longitudinal Health Insurance Database.

The investigators aimed to determine whether retinopathy was caused by hepatitis C infection or the related therapy, so they included the third healthy cohort to compare incidence rates of retinal vascular events.

The researchers believe interferons (IFNs) are an effective way to manage chronic hepatitis C, but noted that the multiple injections required each week is a burden for patients. The chemically modified version, PegIFN, reduces the dosing frequency, and PegIFN/RBV has been used to manage hepatitis C in Taiwan for the past 2 decades.

The patients involved in the study with hepatitis C were more likely to have a blue-collar occupation, live in a rural area or the south of Taiwan, and have a lower income than those in the non-hepatitis C cohort. This group was also less likely to use statins than the non-hepatitis C group, but the prevalence of myocardial infarction, cerebrovascular disease, chronic pulmonary disease, DM, renal disease, hypertension, hyperlipidemia, cataract, diabetic retinopathy, liver cirrhosis, and anemia were all significantly higher.

Over a 2-year period, the cumulative incidence of any retinopathy was about 0.89% in the PegIFN/RBV-treated hepatitis C cohort, 0.15% in the non-treated hepatitis C group, and 0.19% in the healthy cohort. Retinal hemorrhage accounted for almost three-quarters of IFN-associated retinopathy cases among the PegIFN/RBV-treated cohort, but 38% and 20% of any retinopathy cases in the healthy cohort and the non-treated hepatitis C group, respectively.

The greater risk for retinopathy in the treated group was enhanced among retinal hemorrhage and retinal arterial occlusion subtypes, but there was no significant relationship between the untreated hepatitis C group and the healthy cohort. Any retinopathy event was significantly associated with PegIFN/RBV therapy, the study authors said, regardless of whether the patient received an effective hepatitis C treatment (for example, greater or less than 24 weeks).

The study authors also found that the PegIFN/RBV group had a significantly increased risk of anemia compared to the healthy cohort and the untreated hepatitis C cohort. Additionally, there was a significantly increased risk of thrombocytopenia in both hepatitis C groups compared to the group without hepatitis C, but the fact of being treated with PegIFN/RBV was not significant.

“We identified a significantly increased risk of retinal hemorrhage, but a similar risk of retinal vascular occlusions, in the HCV cohort treated with PegIFN/RBV compared with the hepatitis C-untreated cohort,” the study authors concluded. “Because most cases of retinal hemorrhage are considered benign and reversible, and advanced events are infrequent, we suggest that routine fundus examination is not required except in patients with complaints of subjective vision changes.”