Current epidemiology of HCV in Sicily: the RESIST-HCV model

Background: Real-world data to guide hepatitis C virus (HCV)- related public health initiatives and linkage to care of patients are lacking in our region. Aims: To describe the epidemiological features of a large cohort of patients with chronic HCV infection from Sicily included in a regional network aimed at DAA treatment (RESIST-HCV). Methods: Demographic and clinical data were recorded on a web-based platform before starting treatment with DAAs. Gender, year of birth, HCV genotype, co-infections, stages of liver disease and co-morbidities were analyzed. Chi-square with Yates correc- tion was appliedto assess the differences between cohorts. Results: Overall, 15,270 patients were registered on the HCV- RESIST platform from March 2015 to March 2019. The analysis of demographic and viral features showed a clear-cut bimodal distribution, defining two cohorts of patients. The first (cohort 1) includes 9.939 patients (65%) born between the years 1930 and 1959, while the second (cohort 2) included 5.331 patients (35%) born between 1960 and 1999. When comparing the two cohorts, cohort 1 had a higher rate of infection with HCV Gt 1b or 2 (90% vs 47%; p<0.0001), higher rate of cirrhosis (49.5% vs 37.5% in cohort 2; p < 0.001), hepatocellular carcinoma (3.3% vs 0.6%; p < 0.0001), diabetes (26.8% vs 10.3%; p < 0.0001) and of arterial hypertension (50.4% vs 13.5%; p < 0.0001). By converse, in cohort 2 there was a higher proportion of males (71.3% vs 48.7%; p < 0.0001), subjects naïve to IFN-based treatment (66.2% vs 62.5%; p < 0.0001), infection with HCV Gt 1a, 3 or 4 (53% vs 10%; p < 0.0001), HIV co-infection (7.8% vs 1%; p < 0.0001), and PWIDs(12% vs 1%; p < 0.0001). Conclusions: In Sicily, a region where HCV is still endemic, chronic HCV infection has a bimodal distribution, with two dif- ferent cohorts affected. One cohort reflects a first epidemic wave, mostly fueled by Gt 1b and 2, through unsafe medical prac- tices and non-sexual intrafamilial spreading between 1940 and 1990. About half of these patients has developed cirrhosis and many have co-morbidities that may worsen the prognosis. Another cohort originated between 1970 and 2000 mostly through nee- dle sharing and unsafe sex, thus frequently associating with HIV, and is sustained mostly by Gt1a and 3. In order to reach the WHO elimination targets by 2020, graduated screening poli- cies according to this mode of distribution of HCV should be devised.