Epidemiology of thrombocytopenia in patients with chronic hepatitis C: more than meets the eye

Summary.  Thrombocytopenia is likely the most common haematological abnormality that can be diagnosed in patients affected by chronic liver disease. In these patients, the presence of thrombocytopenia may have significant clinical implications. In fact, it can be a limiting factor when considering invasive procedures and may hamper the outcome of antiviral therapy with interferon. The prevalence of decreased platelet count in patients with chronic hepatitis C has been assessed in various studies that evaluated heterogenous patient populations and used various platelet count threshold to identify thrombocytopenia. This review shows that the prevalence of thrombocytopenia in these patients is variable and mainly depends upon the severity of the underlying liver disease and the criterion used to identify this haematological abnormality. Furthermore, the results of this epidemiological review provide an indirect evidence that confirms the multiplicity of aetiological factors underlying the pathophysiology of thrombocytopenia in chronic hepatitis C patients. Lastly, this study shows that up to 25% of patients treated with interferon may develop some degree of thrombocytopenia, and this may be associated with decreased sustained virological response rates.