Preliminary retrospective analysis of patient outcomes associated with subcutaneous c1inh prophylaxis for hereditary angioedema

Introduction

We designed this study to gain a more holistic understanding of clinical and quality-of-life (QOL) impacts of subcutaneous C1INH (C1INH[SC]) used as long-term prophylaxis (LTP) in patients with hereditary angioedema (HAE), as well as on-demand medication use patterns.

Methods

A hybrid design combining semi-structured, qualitative interviews was used in parallel with a retrospective medical records review. Participants (n=16) were adults (≥18 years) with type I/II HAE using C1INH(SC) as LTP for ≥1 year. Interviews were thematically analyzed using qualitative methods to identify baseline symptoms, treatment impacts and changes. Medical records were reviewed for 12 months prior and after starting C1INH(SC) LTP for data relating to HAE attacks, attack treatment, and patient impact.

Results

Fifteen of 16 patients experienced a reduction in attack frequency from baseline (12 months on-demand only prior to C1-INH(SC) start) to post-treatment with C1-INH(SC) at 12 months. Two-thirds of patients who responded noted a reduction in attack severity (8/12). Of 12 patients who reported rescue medication use, 7 (58%) used it for every attack pre-C1INH(SC) and 6 (50%) for every attack while on C1INH(SC). One of 12 patients (8.3%) never used rescue medication while on C1INH(SC). Improvements in QOL included emotional/mental health (n=7), social life/relationships (n=5), and daily activities (n=5).

Conclusions

The preliminary results of this hybrid chart review/qualitative research study indicate that implementation of C1INH(SC) as LTP resulted in a decrease in HAE attacks and use of rescue medication, as well as enhanced patient confidence/QOL. Full results of this retrospective study will be presented at ACAAI 2022.