Routine clinical care for chronic immune thrombocytopenia purpura in Denmark, 2009-2015.

To describe routine treatment and clinical characteristics of patients with chronic ITP (cITP). We used data from Danish nationwide registers and medical records to examine routine clinical care, including splenectomy and medical treatment, of Danish patients with chronic immune thrombocytopenia (cITP, defined as two or more ITP diagnoses at least 6 months apart), i.e. treatment initiation before cITP diagnosis and treatment initiation within one year post-diagnosis for treatment-naïve patients. Nearly half of all 964 cITP patients diagnosed during 2009-2015 initiated treatment between initial ITP diagnosis and chronic onset; 43% received glucocorticoids, 12% received IVIG and 18% received rituximab. Within one year post-diagnosis, 9.2% of previously untreated patients commenced therapy, most often corticosteroids and rituximab. Our results are in line with findings of recent studies from other countries. We found that corticosteroids, IVIG, and rituximab are common first- choice of ITP drugs. Bleeding events occurred in nearly one third of treated patients in the year before cITP diagnosis and in 5% of the treatment-naïve patients. A substantial number of patients do not need treatment during the first 6-12 months. However, some of these patients will subsequently need treatment as the disease may worsen, indicating the need for continuous follow-up of these patients.