Letting the patients speak: an in-depth, qualitative research-based investigation of factors relevant to health-related quality of life in real-world patients with hereditary angioedema using subcutaneous C1 inhibitor replacement therapy

BACKGROUND: While many studies of effective hereditary angioedema (HAE) therapy have demonstrated improved health-related quality of life (HRQoL) using validated instruments, specific reasons behind the improved scores have never been investigated using qualitative methods. A non-interventional, qualitative research study was designed to investigate the reasons for improvements in HRQoL while using effective prophylaxis, in this case subcutaneous C1INH (C1INH[SC]) replacement therapy. METHODS: Adult patients with HAE-C1INH type 1 or 2 who had been using C1INH(SC) for ≥ 3 consecutive months were recruited through four HAE specialty practices in the US to participate in a 60-min phone interview performed by a trained qualitative research specialist (ICON plc) using a semi-structured interview guide with open-ended questions developed with the Angioedema Quality of Life (AE-QoL) items in mind. Interview transcripts were analyzed using thematic analysis methods to identify concepts (specific symptoms/impacts) and themes (higher-level categories grouping related concepts). A cross-mapping exercise was performed between interview-identified concepts and items included in the AE-QoL. RESULTS: Fourteen patients were interviewed and included in the analysis (age range, 28–82 years [mean 47.5 years]; 64% female; 93% white). In 10 interviews, patients mentioned having no or nearly no HAE attacks, no longer feeling limited by HAE, less HAE-related anxiety/worry and depression, an improved ability to travel, fewer emergency room/hospital visits, and ease of administration of C1INH(SC), including not requiring assistance from others. Other commonly expressed concepts included: increased feelings of confidence, independence, optimism, and normalcy; less absence from work/school; better productivity; improved sleep and energy; healthier family relationships; and improved cognition. While all AE-QoL items emerged from patient interviews, a number of identified concepts were not addressed by the AE-QoL, including sensitivity to various potential attack-triggers (e.g., stress/anxiety, sports), attack frequency, not having to cancel social plans, improvements in ability to perform day-to-day tasks, and a lower burden from medical visits. CONCLUSIONS: From these interviews, a large number of common themes and concepts emerged: a greater sense of freedom and normalcy, increased productivity, and improved interpersonal relationships while using convenient and effective prophylaxis. These findings provide insights into real-world experiences and the many facets of HRQoL that are important to patients with HAE-C1INH. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13223-021-00550-5.