Development of the Angioedema Control Test-A patient-reported outcome measure that assesses disease control in patients with recurrent angioedema.

BACKGROUND: Recurrent angioedema (AE) is an important clinical problem in the context of chronic urticaria (mast cell mediator-induced), ACE-inhibitor intake and hereditary angioedema (both bradykinin-mediated). To help patients obtain control of their recurrent AE is a major treatment goal. However, a tool to assess control of recurrent AE is not yet available. This prompted us to develop such a tool, the Angioedema Control Test (AECT). METHODS: After a conceptional framework was developed for the AECT, a list of potential AECT items was generated by a combined approach of patient interviews, literature review and expert input. Subsequent item reduction was based on impact analysis, inter-item correlation, additional predefined criteria for item performance, and a review of the item selection process for content validity. Finally, an instruction section was generated, and an US-American-English version was developed by a structured translation process. RESULTS: A 4-item AECT with recall periods of 4 weeks and 3 months was developed based on 106 potential items tested in 97 patients with mast cell mediator-induced (n = 49) or bradykinin-mediated recurrent AE (n = 48). Eighty-four items were excluded based on impact analysis. The remaining 22 items could be further reduced by a method-mix of inter-item correlation, additional predefined criteria for item performance and review for content validity. CONCLUSIONS: The AECT is the first tool to assess disease control in recurrent AE patients. Its retrospective approach, its brevity and its simple scoring make the AECT ideally suited for clinical practice and trials. Its validity and reliability need to be determined in future independent studies.

Validation of the Angioedema Control Test (AECT)-A Patient-Reported Outcome Instrument for Assessing Angioedema Control.

BACKGROUND: Recurrent angioedema (RA) is an important clinical problem in routine care and emergency medicine. As of recently, the only validated tools to specifically assess disease status in patients with RA were diary-type activity assessments and angioedema-related quality-of-life questionnaires. Although these tools are particularly helpful in clinical studies, they were not designed to determine disease control or to guide treatment decisions. To close this gap, the Angioedema Control Test (AECT) was published recently. OBJECTIVE: To test the AECT for its validity and reliability, and to identify a cutoff value to aid treatment decisions. METHODS: Two AECT versions with a recall period of 4 weeks (AECT-4wk) and 3 months (AECT-3mo) were tested for their internal consistency and test-retest reliability, convergent and known-groups validity as well as screening accuracy in 81 patients with RA with bradykinin-mediated angioedema, mast cell mediator-mediated angioedema, or idiopathic angioedema. RESULTS: Both AECT versions showed excellent internal consistency reliability with a Cronbach alpha value of more than 0.85 and test-retest reliability with an intraclass correlation coefficient greater than 0.9. The convergent validity of both AECT versions was high. Both tools showed strong correlations with anchors of disease control, angioedema frequency, and health-related quality of life. A stratification of AECT scores into different levels of disease control together with a receiver-operating characteristic curve analysis suggested a cutoff value of 10 or more points to identify patients with well-controlled RA versus less than 10 points to identify patients with poorly controlled disease for both AECT versions. CONCLUSIONS: The AECT is the first valid and reliable patient-reported outcome measure to assess disease control in patients with RA.