Background/Aims 

Hepatitis C virus (HCV) easily undergoes genomic changes, thus accounting for the presence of different genotypes, with different geographic distributions and different outcomes of chronic hepatitis.

Type 1b is frequently found in advanced diseases ; however, since this genotype is the most prevalent in older patients, the association with advanced age and severity of the disease is confounding.

The aim of this study was to assess changes in the prevalence of HCV genotypes by surveying a large population of chronic hepatitis C patients in Northern Italy, and to assess if the high prevalence of genotype 1b in older patients with advanced diseases simply reflects the duration of HCV infection, rather than intrinsic biological properties of HCV.

Methods 

We studied 1368 HCV-RNA positive patients, with histologically proven chronic hepatitis.

Drug addiction, blood transfusions and sporadically acquired infections represented the risk factors.

Results 

Genotype 1b, the most prevalent isolate, and genotype 2a were associated with older age, cirrhosis, sporadically-acquired infections and blood transfusion, while types 1a, 3a, and 4 were associated with younger age, chronic persistent hepatitis and drug addiction.

Patients with a history of transfusions were divided into four groups depending on the period of transfusion.

The prevalence of genotype 1b decreased with time.

Type 3a appeared only after 1979. (...)