Predictive value of risk factors for chronic idiopathic thrombocytopenic purpura in patients with acute type of disease

Abstract

BACKGROUND: Immune thrombocytopenic purpura (ITP) is an autoimmune disease in which autoantibodies react with platelet surface antigens and results in mild to severe thrombocytopenia due to decreased platelet count or inhibition of platelet production. Given the relatively high prevalence of ITP among children and the lack of standard diagnostic testing for the diagnosis of chronic disease, this study evaluated the predictive value of risk factors for chronic ITP in hospitalized patients. METHODS: This prospective cohort study was performed on 65 children with ITP who referred to Ali Asghar and Rasool Akram Hospitals in Tehran, Iran, during the years 2017 and 2018. Relationships between different risk factors, including age of diagnosis, gender, white cell count, primary platelet count, mean platelet volume (MPV), history and type of the previous patient infection, FCG gene mutation, and type of FCG mutation with a chronic disease incidence were investigated using multiple logistic regression model. RESULTS: Of 65 patients, 31 (47.69%) were male and 34 (52.31%) were female included in the study. Twenty-eight patients (43.08%) had acute ITP and 37 (56.92%) had chronic ITP. Frequency of FCG gene mutation in patients with chronic and acute type ITP was 16.36% and 7.27%, respectively (p = 0.51). No association was found between the history of the previous infection and its type with the chronic incidence of ITP. The multiple logistic regression model showed that three factors, including the absolute number of lymphocytes, age of diagnosis, and primary white blood cells (WBC) count were directly linked to chronic ITP. Furthermore, three factors of platelet, sex, and MPV were indirectly related to chronic ITP. In addition, the absolute number of lymphocytes, age of diagnosis and primary WBC count were significantly associated with chronic ITP. The receiver operating characteristic analysis showed that the cutoff rate of these factors was 0.31. Further analysis of these risk factors in comparison with the gold standard demonstrated that the diagnostic sensitivity and specificity of these risk factors for chronic ITP were 73.08% and their specificity was 88.57%, indicating the high importance and predictive power of these risk factors. CONCLUSIONS: According to the results of this study, for the first time in Iran, six risk factors, including the absolute number of lymphocytes, age at diagnosis, sex, MPV level, platelet level at time of diagnosis, and primary WBC count were considered as the most important risk factors affecting the incidence of chronic ITP. Of course, more comprehensive studies can definitely lead to more comprehensive models.