Linking hepatitis C virus infection to pre-1994 blood transfusions in female patients.

Introduction: Most blood transfusions occur in female patients. The introduction of serologic screening practices by blood banks reduced the transfusion-related rate of infection with hepatitis C virus (HCV). In Mexico patients with pre-1994 transfusion history are at high risk of being detected with HCV infection. We aimed at establishing an interrelationship between two variables: pre-1994 transfusion history and rate of infection in women treated in the Guadalajara Metropolitan Area hospitals, in Mexico.

Methods: Analytical observational case-control study which included both non-infected women and patients diagnosed with hepatitis C virus infection, in whom the pre-1994 transfusion history was determined. The cases were 150 women with confirmed hepatitis C virus serologic diagnosis. The controls were 150 women whose hepatitis C virus-detection serologic tests had yielded negative results.

Results: An odds ratio of 9.07 (95% CI: 5.37 – 15.3; p< 0.001) was found where the rate of infection for the case group was 0.72 while the control group had a ratio of 0.22; population attributable risk (PAR) was 0.64 (95% CI: 0.53 – 0.73), while etiologic fraction was 0.88 (95% CI: 0.81 – 0.93).

Conclusions: Among women, having been exposed to pre-1994 blood transfusion means a risk 9.07 times higher than not being exposed to blood transfusion in the same time frame.