Pegylated interferon and ribavirin in real life: Efficacy versus effectiveness
Authors: Ângelo Zambam de Mattos, Paulo Roberto Lerias de Almeida, Cristiane Valle Tovo, Angelo Alves de Mattos
Journal: Hepatology (2010)

We read the interesting article by Feuerstadt et al.1 on the effectiveness of the treatment of hepatitis C with pegylated interferon and ribavirin in urban minority patients. We reported a population-based cohort of patients who were treated with this regimen in Brazil and experienced better results, although the results were worse than those presented in phase 3 trials.2 Our study evaluated virtually all patients treated for hepatitis C in a Brazilian state, so differences with respect to the clinical trials cannot be explained by the treatment of minorities; besides, our state population is predominantly European in origin and does not fit within the groups suspected of having worse responses. It also seems important to consider that even Caucasian patients in Feuerstadt et al.'s cohort had worse results than those in the efficacy trials. Although the sustained virological response (SVR) rate ranged from 54% to 63% (42%-52% for genotype 1) in the trials,3-5 Feuerstadt et al.1 showed an SVR rate of 21% (14% for genotype 1 and 37% for genotype 2/3) in a sample of 255 patients with a mean age of 50 years (60% were male, 68% had genotype 1, and 29% had cirrhosis). We, on the other hand, found an SVR rate of 35.3% in a sample of 323 genotype 1–monoinfected individuals with a mean age of 51.1 years (55.7% were male, 57% had a pretreatment viral load > 600,000 IU/mL, 73.9% had a METAVIR score of F3 or F4, and 30% had cirrhosis).2 The mean age and the proportion of patients with advanced fibrosis were much greater in both cohorts in comparison with the clinical trials.1-5 In Feuerstadt et al.'s study, 23% of the patients discontinued treatment because of side effects, whereas only 10.2% did so in our study. For both cohorts, intention-to-treat analysis was used.1, 2 A factor that could help to explain the differences between these two effectiveness studies is that for Feuerstadt et al.,1 26% of the patients were lost to follow-up, whereas we did not have such a problem,2 probably in part because the treatment is offered by the Brazilian Government, which provides more rigid control and ensures that the treatment is delivered until its completion once it has been started. It is important to remember that losses of more than 20% in cohort studies may diminish the confidence in their results. It is true that other authors have published cohorts with results closer to those shown in the trials. A recent review of the matter claims that the results of most cohorts collectively confirm those of the trials.6 We understand, however, that a careful evaluation must be performed before such a conclusion can be drawn; the aforementioned review is not systematic and includes results published in abstracts and in preliminary analysis and other results with important methodological flaws. A systematic review of this matter is of the utmost importance, although our impression is that the results of the clinical trials do not entirely correspond to those we find in real life, as already shown for interferon and ribavirin in the past.7 Ângelo Zambam de Mattos M.D.*, Paulo Roberto Lerias de Almeida Ph.D.* , Cristiane Valle Tovo Ph.D.* , Angelo Alves de Mattos Ph.D.*, * Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil, Hospital Nossa Senhora da Conceição, Porto Alegre, Brazil.