Study design
A new PRO instrument: HAE Evaluation of Prodromes and Attacks (HAE-EPA)
was utilized in this study to assess patient reports. Its description
and validation process is detailed elsewhere.13 This
instrument consists of personal and health-related data, evaluation of
prodromes and evaluation of attacks, and was powered to collect and
analyze recent prodrome/attack data from the participating patients.
For practical purposes, we chose to describe the range of signs and
symptoms ocurring in each body system relevant to HAE (domain) as a
’cluster’.11,12 Accordingly, ’abdominal
cluster’ represented all the
recognizable gastrointestinal (GI) signs and symptoms reported by the
patients (i.e. nausea, vomiting, abdominal pains, diarrhea etc.). This
method has proven useful and easy to comprehend by both patients and
investigators, and is also amenable to statistical
analysis.10-13 Most relevant clusters in this study
included: facial, oropharyngeal, abdominal, extremities (skin and
subcutaneous tissue) and urogenital domains..
Each
cluster of the involved body
location is evaluated by specific items, adapted to its unique
charachteristics (i.e. abdominal cluster-9 items, Facial-4,
urogenital-7, oropharyngeal-8, Extremities-3). Each cluster’s
involvement was represented by four scalable dimensions, measured by a
visual analog score (Likert scale, VAS): pain (scaled), severity (i.e.
degree of swelling), impairment (i.e. interference with daily
activities) and functionality (i.e. use of a limb).