Background Inosine triphosphatase (ITPA) genotyping is used for predicting anaemia in patients with genotype 1 chronic hepatitis C. The AA and CA genotypes have the lowest incidence of anaemia.

Purpose To compare the incidence of anaemia, the reduction in ribavirin (RBV) dose and the use of darbepoetin in patients treated with boceprevir or telaprevir before and after the introduction of ITPA genotyping in a tertiary care hospital.

Material and methods Observational, pre-post intervention study using pharmacotherapeutic records of patients treated with telaprevir or boceprevir before and after the introduction of ITPA genotyping. Anaemia was defined as haemoglobin (Hb) <10.5 mg/dL. Baseline characteristics were age, sex, fibroscan, basal Hb, nadir Hb and ITPA genotype. Homogeneity of baseline characteristics was evaluated by the t-test. Comparisons of the incidence of anaemia, the reduction of RBV dose and the use of darbepoetin were made with the independent proportions test.

Results Before genotyping 37 patients were included (27 male, 10 female): Mean fibroscan was 22 kpa, mean basal Hb was 15.6 mg/dL and mean nadir Hb was 10.4 mg/dL. After genotyping 20 patients were included (16 male, 4 female): 18 patients were CC (90%) and two were AC (10%). Mean fibroscan was 11.9 kpa (significantly lower than before genotyping). Mean basal Hb was 16.1 mg/dL and mean nadir Hb was 10.9 mg/dL.

Comparison of before and after results. Reduction in RBV dose: 43.2% vs. 40% (p = n.s.); anaemia: 35.1% vs. 45% (p = n.s.); and treatment with darbepoetin: 32.4% vs. 25% (p = n.s.)

Conclusion Although the reduced use of darbepoetin suggests the practical utility of this resource, a higher percentage of patients experienced anaemia after ITPA genotyping was available. This is possibly because the RBV dose was reduced by less than before genotyping even though 90% of patients were the CC (pro-anaemia) genotype. Greater emphasis should be placed on this resource.

No conflict of interest.