We think that an explanatory strategy for building the Cox model, using time-dependent covariates and a propensity score to adjust for the potential confounding factors, would have enriched the study.3–5 In this way, instead of being FDA-approved Drug Library cost driven by significance tests, covariates would have entered and remained in the explanatory model as a result of their modification effect on the association of therapy and mortality.3 Moreover, they could have checked for confounding and likely interactions to explore whether the observed effect was the same in different subsets of patients, as the editorialists claimed. Besides, the use of time-dependent covariates would have allowed fine-tuning of the

beta-blocker therapy duration and would have better addressed its influence on outcomes.4 Finally, a propensity score, which defines the probability that an individual will receive a specific treatment based on his or her pretreatment characteristics, is useful for overcoming the imbalance

between check details groups when treatment assignment is not random.5 Specifically, in Serstè et al.’s study, the propensity score would have corrected the effect of beta-blockers for patient characteristics such as the presence of varices, which heavily conditions their prescription. With such an analysis, the focus of the model would have been the influence of beta-blockers on survival rather than the identification of factors influencing survival; hence, it would have offered more clues to the causal effect. The proposed approach would add robustness to the interesting results provided by Serstè et al. Agustín Albillos M.D., Ph.D.* ‡, Javier

Zamora M.D., Ph.D.† §, * Departments of Gastroenterology and Hepatology, Ramón y Cajal Institute of Health Research, University of Alcalá, Madrid, Spain, † Clinical Biostatistics, Ramón tuclazepam y Cajal University Hospital, Ramón y Cajal Institute of Health Research, University of Alcalá, Madrid, Spain, ‡ Network Centers for Biomedical Research in Hepatic and Digestive Diseases Carlos III Institute of Health, Madrid, Spain, § Epidemiology and Public Health, Carlos III Institute of Health, Madrid, Spain. “
“The hepatitis C virus (HCV) is a small, parenterally transmitted RNA virus that is acquired today almost exclusively by the use of unsterile needles. It occurs in sixdistinct genotypes, genotype 1 being the most prevalent in North America, Europe, and Japan. HCV causes an acute hepatitis that is clinically silent in most cases and persists in the majority (80%) of patients leading to chronic hepatitis. Chronic hepatitis C remains clinically silent, and progresses to cirrhosis in about 10% of patients within 20 years. Once cirrhosis is established, morbidity and mortality from hepatic decompensation and hepatocellular carcinoma ensues. Concomitant alcohol consumption, male gender, co-infection with HIV or HBV, and older age at time of infection accelerates the progression to cirrhosis.