Platelet count is closely associated with the severity of liver injury in patients with chronic hepatitis B virus infection: A cross-sectional study.

Although the platelet count may provide clues regarding the severity of liver disease, there are currently no available data supporting the utility of the platelet count to evaluate the degree of liver injury in patients with chronic hepatitis B virus (HBV) infection. The present study aimed to determine the association between the platelet count and the severity of liver injury in patients with chronic HBV infection. A total of 941 patients were included and were stratified into a Child-Turcotte-Pugh (CTP) class A group and a CTP class B/C group using the CTP scoring system. A total of 53 patients underwent liver biopsy. The pathological stage F4 was defined as cirrhosis based on the METAVIR scoring system. Compared with that in patients with CTP class A, the platelet count in patients with CTP class B/C was lower (P<0.001). Similarly, for patients with normal alanine aminotransferase (ALT) levels, the platelet count was significantly different between the CTP class B/C and A groups (P<0.001). The platelet count was inversely correlated with the CTP score (r=-0.420, P<0.001) and independently associated with CTP grade B/C [odds ratio (OR), 0.994; 95% CI, 0.990-0.999; P=0.009]. The area under the receiver operating characteristic curve (AUC) of the platelet count to distinguish CTP grade B/C from A was 0.712 and 0.791, respectively, in all patients with HBV infection and the subset with normal ALT levels. In addition, compared to patients with chronic hepatitis B, patients with cirrhosis had a lower platelet count and higher aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) (P<0.001). The platelet count was inversely correlated with FIB-4 (r=-0.855, P<0.001) and APRI (r=-0.741, P<0.001). The AUC for the platelet count to distinguish cirrhosis from chronic hepatitis B was 0.927 (sensitivity, 78.76%; specificity, 92.22%). Among patients who underwent liver biopsy, the platelet count in those with F4 was lower compared with that in patients with ≤F3 (P=0.013). The platelet count was inversely correlated with the pathological stage (r=-0.295, P=0.032) and was independently associated with F4 (OR, 0.978; 95% CI, 0.960-0.997; P=0.026). The AUC of the platelet count to distinguish F4 from patients with ≤F3 was 0.761. In conclusion, the platelet count may be used as a non-invasive marker to assess the severity of liver injury and of liver fibrosis in patients with chronic HBV infection.