Influencing Factors on Prognosis of Adult Patients with Chronic Primary ITP Treated with Rituximab and Predictive Value of Platelet Count

Abstract

To investigate the influencing factors on prognosis of adult patients with chronic primary immune thrombocytopeuia (ITP) after rituximab treatment and predictive value of platelet (Plt) count. Clinical data of 52 adult patients with chronic primary ITP treated with rituximab from January 2012 to December 2016 were retrospectively analyzed, including 32 patients for failed in treatment as group A and 20 patients for succeeded in treatment as group B. The independent risk factors influencing the clinical efficacy of rituximab were analyzed. The influence of CD41+ megakaryocyte count in bone marrow diagnosed for first time on the response rate of patients with 1-year followed-up were observed, and the Plt count were calculated to predict the clinical efficacy index and the best cut-off point. The CD41+ megakaryocyte count in bone marrow for first time treatment in group B were significantly higher than that in group A (P＜0.05). Multivariate Logistic regression analysis showed that the number of CD41+ megakaryocytes in bone marrow＜150 at first diagnosis was the independent risk factor influencing the clinical efficacy of rituximab (OR=5.40，95%CI：1.82-15.66，P=0.00). The response rate of 1-year followed-up in patients with CD41+ megakaryocyte count ≥150 at first diagnosis was significantly higher than that of CD41+ megakaryocyte count ＜150 (P＜0.05). The Plt count level in group B was significantly lower than that in group A at the 3rd, 14th, 21th, 30th, 60th, 90th, 180th, 270th and 360th days after first treatment with rituximab (P＜0.05). ROC curve analysis showed that the best cut-off point for Plt count was 50×109/L and AUC was 0.68 at the 14th day after first treatment with rituximab (95%CI: 0.57-0.78, P=0.00). The predictive sensitivity and specificity of clinical efficacy in adult patients with chronic primary ITP treated with rituximab were separately 48.73% and 87.58%, and the AUC in 30th and 60th day after rituximab treatment were separately 0.74 (95%CI: 0.64-0.87, P=0.00), 0.93 (95%CI：0.82-0.98，P=0.00). Adult patients with chronic primary ITP may possess long-term remission after rituximab treatment, but the prognosis is poor for patients with bone marrow megakaryocyte count ＜150. The Plt counts in 14th, 30th and 60th days after rituximab treatment can effectively predict the long-term clinical efficacy and guide the formulation of treatment plans.