Objective To determine the impact of therapy on the reported health-related quality of life (HRQoL) in children with primary immune thrombocytopenia (ITP) using the Kids ITP tool (KIT).

Design Secondary data analysis of the international and North American KIT validation studies.

Results 217 children from 6 countries participated in the two studies. The majority of treatments occurred in children with newly diagnosed ITP. There was no statistical difference in age, platelet count and bleeding severity at presentation in those who physicians chose to treat or observe. Self-reported KIT scores did not differ between the two groups. The KIT parent-proxy scores were significantly worse for newly diagnosed children receiving treatment, especially following prednisone.

Conclusions Treatment of ITP does not improve, and may worsen, the HRQoL of children with ITP as measured using the KIT.