Thrombotic Thrombocytopenic Purpura and Evans Syndrome: Validating and Exploring 20 Years of Routine Hospital Care.

Purpose: Few patients scattered among centers complicate investigation of thrombotic thrombocytopenic purpura (TTP) and Evans syndrome (ES). Routinely collected Danish register data captures the total population and includes lifelong follow-up. We aimed to validate registered TTP and ES diagnoses and to explore clinical characteristics.

Patients and methods: We identified all patients in Denmark with diagnosis registrations indicative of TTP or ES in the Danish National Patient Registry 2000-2019, validated diagnoses through medical record review, and extracted and presented data on initial treatment and complications.

Results: Diagnoses for patients registered with TTP and ES were confirmed for 46% and 59%, respectively. Among validated TTP patients the most widespread complications at time of diagnosis were neurological symptoms or deficits, observed in 81% of cases. Other frequent types of complications in TTP patients were any organ failure (32%) and infection (25%). Initial management and complications did not change for patients diagnosed between 2000 and 2009 and 2010 and 2019, and survival remained constant (overall mortality 26%, median follow up of 8.4 years). Treatments and complications also remained unchanged for ES patients.

Conclusion: Overall, diagnostic accuracy, complications and prognosis have remained relatively constant for patients over the study period. These now validated cohorts of Danish TTP and ES patients will be utilized in future studies to examine long-term health outcomes.