Using Nordic Score With Pediatric ITP

Investigators found that the Nordic score —which has been validated as a useful clinical prediction tool for adult patients with immune thrombocytopenia (ITP)—also can help predict the clinical course among pediatric patients with ITP. 

The researchers noted in their study, published in the journal Blood, that 25-30% of children with ITP develop chronic disease. However, until recently the use of the Nordic score has been limited among pediatric patients and its value as a prognostic tool to predict the risk of developing chronic ITP has been poorly understood.

“We hypothesized that Nordic score and patient characteristics will be predictive of ITP resolution or development of chronic ITP,” the authors wrote. To test this hypothesis the investigators conducted a retrospective chart review of all children diagnosed with ITP at between May 2008 and May 2019 at the Ann & Robert H. Lurie Children's Hospital of Chicago. They reviewed the patients' age, sex, presenting signs and symptoms, laboratory values, treatment decisions, and clinical outcomes. A total of 308 patients were included, with a median age of 5 years; 54.5% were male.

“The Nordic score was calculated with 6 clinical features from diagnosis: abrupt onset <14 days, age < 10 years, preceding infection <1 month, platelet count < 5x10 9/L, wet purpura, and male sex,” the authors explained. “High scores (10-14) predict a brief disease course (<3 months), whereas low scores (0-4) predict a more prolonged course. Primary outcomes included complete response (CR), defined as platelets 100 x10 9/L on 2 occasions >7 days apart), recurrence (platelets < 100 after achieving CR), development of chronic ITP, and resolution (long term normal platelet count).”

Among the secondary outcomes measured were early response (platelets 30 x10 9/L in <1 week), time to CR, duration of CR (months between CR and recurrence), and time to resolution.

Just over half of the patients presented with platelets < 10 x10 9/L and 42% had a bleeding score of 3 or higher at diagnosis; only 3% were severe. The median Nordic score among this cohort was 10 (IQR 6-11). Some 64% of patients were treated at diagnosis with 98% receiving intravenous immunoglobulin (IVIG). Some 32% of pediatric patients reviewed developed chronic ITP. Approximately 36% of these patients experienced disease resolution over median 25 months.

“Using multivariate regression analysis adjusted for age, abrupt onset, viral symptoms, and other variables, Nordic score was the only independent predictor of all primary outcomes,” the authors reported. “Higher Nordic score group had increased likelihood of CR (OR 6.2, 5.6-6.8) and disease resolution (OR 6.8, 5.1-8.9). Lower Nordic score group was associated with increased likelihood of recurrence (OR 6.5, 5.3-6.9) and development of chronic ITP (OR 8.6, 6.5-11.4). Additionally, higher Nordic score group was associated with increased time to recurrence and duration of response, decreased time to CR and resolution.”

The investigators concluded, “In our cohort, low platelet count and bleeding symptoms were drivers of upfront treatment in pediatric ITP. Treatment initiation, associated with Nordic score, was predictive of faster increase in platelet count; however, it had no impact on overall disease trajectory or likelihood of complications. Our analysis demonstrates that Nordic score is an independent predictor of CR, resolution, recurrence, and development chronic ITP. Nordic score is a useful, simple prognostic tool that has the potential to help predict clinical course of pediatric ITP and identifying patients who may benefit from closer monitoring.”

—Rebecca Mashaw

Reference:
Zeng XL, Badawy SM. Evaluating clinical outcomes and potential prognostic factors among 308 children and adolescents with immune thrombocytopenia (ITP): An 11-year retrospective cohort study. Blood. 2021;138-S1(11): 4053. https://doi.org/10.1182/blood-2021-154344