OBJECTIVES: Hereditary angioedema (HAE) due to C1-INH deficiency is a rare orphan disease characterised by spontaneous attacks of oedema that interrupt the "normal" attack-free state. HAE is known to impact patient quality of life (QoL) and productivity but, despite a recent increase in treatment options, there remains a shortage of data to quantify these important aspects of the HAE disease.  Sweha-Reg, a population based census of HAE in Sweden, implemented a retrospective patient survey to address this data gap and define the burden of HAE in Sweden. METHODS: A retrospective registry study of Swedish patients with HAE (captured by the Sweha-Reg census). Data was collected using a paper-based survey.  Patients completed EQ5D-5L questionnaires for attack-free and acute HAE attack states. To be included in the analysis, patients must have suffered an attack in the last 12 months. Questions related to patient demographics (age and sex) and other parameters (such as attack location and severity) were included to better understand the burden of HAE. EQ5D-5L values were estimated for both HAE disease states and then compared with other variables; utilities were also calculated.  Patient-reported sick-leave was analysed to understand the factors responsible for productivity loss in patients with HAE. RESULTS: A total of 105 valid responses were analysed from an initial mailing of 139 surveys (76% response rate).  94% of patients reported an attack in the last 12 months. The total number of attacks reported per patient during one year ranged from 1 to 120. A significant reduction in QoL scores between the attack-free and acute attack states of HAE was observed.  Also, attack location and severity had a clear impact on the utility values. CONCLUSIONS: Results from this Sweha-Reg study provide an insight to the significant impact on QoL and productivity loss that HAE has on patients in Sweden.