Family burden in inherited ichthyosis: creation of a specific questionnaire

Background: The concept of individual burden, associated with disease, has been introduced recently to determine the disability caused by the pathology in the broadest sense of the word (psychological, social, economic, physical). Inherited ichthyosis belong to a large heterogeneous group of Mendelian Disorders of Cornification. Skin symptoms have a major impact on patients' Quality of Life but little is known about the burden of the disease on the families of patients. Objectives: To develop and validate a specific burden questionnaire for the families of patients affected by ichthyosis. Methods: Two steps were required. First, the creation of the questionnaire which followed a strict methodological process involving a multidisciplinary team and families. Secondarily, the validation of the questionnaire, including the assessment of its reliability, external validity, reproducibility and sensitivity, was carried out on a population of patients affected by autosomal recessive congenital ichthyosis. A population of parents of patients affected by ichthyosis was enrolled to answer the new questionnaire in association with the Short Form Q12 questionnaire (SF-12) and a clinical severity score was filled for each patient. Results: Ninety four families were interviewed to construct the verbatim in order to create the questionnaire and a cognitive debriefing was realized. The concept of burden could be structured around five components: economic, daily life, familial and personal relationship, work, and psychological impact. As a result, Family Burden Ichthyosis (FBI) reproducible questionnaire of 25 items was created. Forty two questionnaires were analyzable for psychometric validation. Reliability (Cronbach's alpha coefficient = 0.89), reflected the good homogeneity of the questionnaire. The correlation between mental dimensions of the SF-12 and the FBI questionnaire was statistically significant which confirmed the external validity. The mean FBI score was 71.7 +/- 18.8 and a significant difference in the FBI score was shown between two groups of severity underlining a good sensitivity of the questionnaire. Conclusions: The internal and external validity of the FBI questionnaire was confirmed and it is correlated to the severity of ichtyosis. Ichthyoses, and other chronic pathologies, are difficult to assess by clinical or Quality of Life aspects alone as their impact can be multidimensional. FBI takes them all into consideration in order to explain every angle of the handicap generated.