INTRODUCTION

Hereditary angioedema (HAE) is characterised by recurrent swelling attacks affecting different parts of the body. HAE does not only impact patients’ health-related quality of life (HRQoL), but also affects caregivers’ HRQoL. This is the first Time Trade-Off (TTO) study measuring HRQoL in HAE, using 1 (full health) and 0 (dead) as anchors.

OBJECTIVES

This study aimed to elicit values for HAE health states, describing an attack-free state, different attack locations, and caregiver health state, which describes caring for someone with an HAE attack.

METHODS

Health state vignettes for an abdominal, facial, hand and laryngeal attack as well as an attack-free and caregiver state were developed, informed by findings from a targeted literature review and qualitative interviews. The vignettes were revised following additional interviews with patients, caregivers and a clinical expert. Members of the general public in the United Kingdom (UK) rated all vignettes in TTO videoconference-based interviews which also included a visual analogue scale (VAS).

RESULTS

For the health state vignettes development, qualitative interviews with 8 adult patients, 5 adult patients who are also caregivers, 5 adult caregivers, 2 adolescents (1 patient, 1 patient who is also a caregiver) and 1 clinical expert were performed. The TTO were completed by 100 members of the general public. The TTO values were: attack-free: 0.783 (SD= 0.316), hand: 0.582 (SD=0.380), facial: 0.483 (SD=0.448), abdominal: 0.345 (SD=0.458), and laryngeal: 0.128 (SD=0.529). The caregiver rating was 0.762 (SD=0.303). VAS ratings were similar and consistent.

CONCLUSIONS

This study provides estimates for different HAE attack locations, an attack-free and caregiver health state. The estimates show that HAE has a significant impact on the patient’s and caregivers HRQoL. It is important to include these influences on HRQoL in any future economic evaluations of treatments. Previous published estimates have not differentiated health states by attack location.