Systematic Literature Review of the Economic and Quality of Life Burden of Congenital and Immune-Mediated Thrombotic Thrombocytopenic Purpura

Abstract

Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening blood disorder resulting from ADAMTS13 deficiency, caused by mutations in the ADAMTS13 gene in congenital TTP (cTTP), and by neutralizing antibodies against ADAMTS13 in immune-mediated TTP (iTTP). This systematic review summarizes available economic evaluations, healthcare resource utilization (HCRU), cost, utility, and health-related quality of life (HRQoL) literature in TTP, with a focus on cTTP. Given the limited availability of cTTP-specific data, broader TTP evidence was also reviewed to infer potential implications for cTTP where appropriate.

Methods: Three systematic literature searches were conducted in January 2024 in accordance with PRISMA guidelines, each tailored to identify studies reporting economic evaluations, HCRU/cost data, and utility/HRQoL data respectively. For the economic evaluation and utility/HRQoL reviews, inclusion criteria were broadened to include studies reporting data on iTTP and unspecified TTP from which findings for cTTP were inferred.

Results: In total 431, 989, and 849 records were identified for the economic evaluation, HCRU/cost, and utility/HRQoL reviews, respectively. No economic evaluations were identified for treatments in cTTP populations. Eight economic studies (all in iTTP) were included. Overall, 5 studies found caplacizumab to be cost-effective, whereas 3 did not, highlighting variability across model assumptions and healthcare settings. Six HCRU/cost studies reported that cTTP was associated with frequent hospital interactions, missed work time, and high costs. Fourteen studies (1 in cTTP, 10 in iTTP, and 3 in unspecified TTP) were included in the utility/HRQoL review and showed that TTP is associated with reduced utility scores and lower HRQoL, irrespective of TTP subtype.

Conclusion: These findings underscore the meaningful patient burden observed across the TTP spectrum and highlight the need for further research to evaluate the cost-effectiveness of emerging therapies in cTTP. However, the predominance of iTTP data reflects ongoing challenges in evidence generation for rare TTP subtypes such as cTTP.

Keywords: economic evaluation; health utility; healthcare resource utilization; quality of life; systematic literature review; thrombotic thrombocytopenic purpura.