HAE-AS, a specific disease activity scale for hereditary angioedema with C1-inhibitor deficiency
João Forjaz M1*, Ayala A1*, Caminoa M3, Prior N4, Pérez-Fernández E5, Caballero T2,6,7 on behalf of the DV-HAE-QoL study group#
1National School of Public Health, Institute of Health Carlos III and REDISSEC, Madrid, Spain.
2Allergy Department, Hospital Universitario La Paz, Madrid, Spain
3Clínica Marazuela, Talavera de la Reina, Toledo, Spain.
4Hospital Universitario Severo Ochoa, Leganés, Madrid, Spain
5Research Unit, Hospital Universitario Fundación Alcorcón, Madrid, Spain
6Hospital La Paz Institute for Health Research (IdiPaz), Madrid, Spain.
7Biomedical Research Network on Rare Diseases (CIBERER, U754), Madrid, Spain
*A Ayala and MJ Forjaz should be considered joint first author.
#DV-HAE-QoL study group: W Aberer8, S Betschel9, A Bygum10, D Csuka11, H Farkas11, C Gómez-Traseira2,6, AS Grumach12, I Leibovich13, A Malbran14, D Moldovan15,%, E Mihaly15, K Obtulowicz16, G Porebski16, A Reshef13, S Rodrigues Do Valle17, P Staubach18, M Wiednig8.
8Department of Dermatology, Medical University, Graz, Austria
9Division of Allergy and Clinical Immunology St. Michael's Hospital, Toronto, Canada
10HAE Centre, Odense University Hospital, Denmark, member of European Reference Network (ERN) for Rare and Complex Diseases
11Hungarian Angioedema Reference Center, 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary
12Faculty of Medicine ABC, SP, Brazil
13Allergy, Immunology, and Angioedema Center, Barzilai University Medical Center, Ashkelon, Israel.
14Allergy, Asthma and Immunology Unit, Buenos Aires, Argentina
15Department of Allergology–Immunology, Mures County Hospital, Tìrgu-Mures¸ Romania
16Department of Clinical and Environmental Allergology, Jagiellonian University, Krakow, Poland
17Federal University, Rio de Janeiro, Brazil
18Department of Dermatology, University Medical Center Mainz, Mainz, Germany
%This author is deceased
J Investig Allergol Clin Immunol 2021; Vol. 31(3)
Background: Hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) shows variability in disease activity among patients and within individual patients.
Objective: This study aims at developing a disease activity scale for C1-INH-HAE (HAE-AS) with sound measurement properties.
Methods: Eleven countries participated in a prospective multicentre cohort study. A clinical questionnaire was self-completed by 290 adult patients with C1-INH-HAE. Patients also completed two quality of life (QoL) scales, the SF-36v2 and the HAE-QoL. Rasch analysis and classical psychometric methods were used in a pre-selection of clinical items: number of attacks by location and number of treated attacks, emergency room visits, psychological/psychiatric treatment, missed school/work days in the last 6 months; general health; and impairment in everyday work/activities due to pain.
Results: The sample presented a mean age of 41.5 (SD=14.7; range: 18-84) years, with 69% of females. The final Rasch model with 12 items showed that the HAE-AS had a satisfactory reliability (person separation index = 0.748), local item independence, unidimensionality and no item bias by age or gender. The HAE-AS provided scores in a linear measure, with mean 10.66 (SD=3.92; range: 0-30). Further analysis with classical psychometric methods indicated that the HAE-AS linear measure presented moderate-to-high convergent validity with QoL scales (SF-36v2: physical component, r=-0.33, mental component 0.555; HAE-QoL: -0.61) and good discriminative validity by age, gender and disease severity (p<0.05).
Conclusions: The HAE-AS is a short, valid, reliable and psychometrically sound measure of disease activity for C1-INH-HAE, which may be useful for research studies.
Key words: C1-INH-HAE, Clinical activity, Hereditary angioedema, Psychometric properties, Rasch analysis