PB0322 - Burden of illness associated with congenital thrombotic thrombocytopenic purpura: A systematic review

Background: Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultra-rare thrombotic disorder caused by an inherited deficiency of the von Willebrand factor-cleaving enzyme ADAMTS13.

Aims: To synthesize knowledge on the disease burden experienced by patients with cTTP.

Methods: A systematic review of observational studies published between January 01, 2010 and February 11, 2022 was conducted in accordance with the PICOTS (population, intervention, comparator, outcomes, timing, setting) criteria. The target population comprised patients with cTTP. Outcomes of interest included acute episodes, complications, mortality, patient-reported outcomes, and disease management. Indexed publications (Ovid® MEDLINE and Embase) were searched, supplemented by pragmatic searches of the grey literature and snowballing of references lists. Case reports, clinical trials, and non-clinical/experimental studies were excluded. Two reviewers independently conducted the study selection and data extraction.

Results: Twenty eligible sources were identified. Median time between first symptoms and cTTP diagnosis was 13.4 (range: 0–70) years (1 source). The incidence rate of acute episodes ranged from 0.19–0.77/person-year across 4 publications based on an international registry (Table 1). The most common triggers of acute episodes were infection and pregnancy (4 sources). Disease-related complications included stroke/transient ischemic attack, kidney disease, neurocognitive disorders, and cardiac injury (7 sources; Table 2). Mortality was observed in up to 14.2% of patients across different populations and follow-up periods (10 sources). A reduced ability to work and/or study, financial distress, and a negative impact on mental health were reported by patients as important outcomes of cTTP (1 source). The number of patients who received regular plasma prophylaxis ranged between 45.5% and 80% (5 sources).

Conclusion(s): Based on limited data, patients with cTTP appear to experience a high burden of illness, including acute episodes, multiple complications, and mortality. Timely diagnosis of cTTP and improved patient management can potentially reduce this disease burden.