A Clinical Prediction Score for Transient versus Persistent Childhood Immune Thrombocytopenia.

BACKGROUND Childhood immune thrombocytopenia (ITP) is an autoimmune bleeding disorder. The prognosis (transient, persistent or chronic ITP) remains difficult to predict. The morbidity is most pronounced in children with persistent and chronic ITP. Clinical characteristics are associated with ITP outcomes, but there are no validated multivariate prediction models. OBJECTIVE We developed and validated the Childhood ITP Recovery Score to predict transient vs. persistent ITP in children with newly diagnosed ITP. METHODS Patients with a diagnosis platelet count ≤20x109 /L and age below 16 years were included from two prospective multicenter studies (NOPHO ITP study, N=377 [development cohort]; TIKI trial, N=194 [external validation]). The primary outcome was transient ITP (complete recovery with platelets ≥ 100 x 109 /L three months after diagnosis) versus persistent ITP. Age, sex, mucosal bleeding, preceding infection/vaccination, insidious onset and diagnosis platelet count were used as predictors. RESULTS In external validation, the score predicted transient vs. persistent ITP at three months follow-up with an AUC ROC of 0.71. In patients predicted to have a high chance of recovery, we observed 85%, 90% and 95% recovered three, six and twelve months after the diagnosis. For patients predicted to have a low chance of recovery, this was 32%, 46% and 71%. The score also predicted cessation of bleeding symptoms and the response to Intravenous Immunoglublins (IVIg). CONCLUSION The Childhood ITP Recovery Score predicts prognosis and may be useful to individualize the clinical management. In future research, the additional predictive value of biomarkers can be compared to this score.