Thrombocytopenia and PT-INR in patients with anorexia nervosa and severe liver dysfunction

BACKGROUND: We previously reported a case that led us to hypothesize that decreased production of thrombopoietin (TPO) leads to thrombocytopenia in patients with anorexia nervosa (AN) with severe liver dysfunction and that prolonged prothrombin time-international normalized ratio (PT-INR) predicts thrombocytopenia in such cases. To validate this hypothesis, we report another case in which TPO levels were measured. In addition, we examined the association between prolonged PT-INR and thrombocytopenia in such patients. MAIN BODY: Similar to the previously reported patient, a patient with AN with severe liver dysfunction showed that TPO levels increased after improvements in liver enzyme levels and PT-INR, followed by recovery of platelet count. In addition, a retrospective study was also conducted to review patients with AN whose liver enzyme levels were > 3 × the upper limit of normal (aspartate aminotransferase > 120 U/L or alanine aminotransferase > 135 U/L). The study included 58 patients and showed a correlation coefficient of -0.486 (95% confidence interval [CI], -0.661 to -0.260; P < 0.001) between maximum PT-INR and minimum platelet count. These patients showed higher PT-INR (β, 0.07; 95% CI, 0.02 to 0.13; P = 0.005) and lower platelet count (β, -5.49; 95% CI, -7.47 to -3.52; P < 0.001) than the 58 matched control patients without severe liver dysfunction, even after adjusting for body mass index. CONCLUSIONS: In patients with AN with severe liver dysfunction, prolongation of PT-INR could predict thrombocytopenia, which may be mediated by decreased TPO production due to decreased hepatic synthetic function.