Self-administered version of the Fabry-associated pain questionnaire for adult patients.

BACKGROUND: Fabry-associated pain may be the first symptom of Fabry disease (FD) and presents with a unique phenotype including mostly acral burning triggerable pain attacks, evoked pain, pain crises, and permanent pain. We recently developed and validated the first Fabry Pain Questionnaire (FPQ) for adult patients. Here we report on the validation of the self-administered version of the FPQ that no longer requires a face-to-face interview but can be filled in by the patients themselves allowing more flexible data collection. METHODS: At our Würzburg Fabry Center for Interdisciplinary Treatment, Germany, we have developed the self-administered version of the FPQ by adapting the questionnaire to a self-report version. To do this, consecutive Fabry patients with current or past pain history (n = 56) were first interviewed face-to-face. Two weeks later patients' self-reported questionnaire results were collected by mail (n = 55). We validated the self-administered version of the FPQ by assessing the inter-rater reliability agreement of scores obtained by supervised administration and self-administration of the FPQ. RESULTS: The FPQ contains 15 questions on the different pain phenotypes, on pain development during life with and without therapy, and on impairment due to pain. Statistical analysis showed that the majority of questions were answered in high agreement in both sessions with a mean AC1-statistic of 0.857 for 55 nominal-scaled items and a mean ICC of 0.587 for 9 scores. CONCLUSIONS: This self-administered version of the first pain questionnaire for adult Fabry patients is a useful tool to assess Fabry-associated pain without a time-consuming face-to-face interview but via a self-reporting survey allowing more flexible usage.

A comprehensive Fabry-related pain questionnaire for adult patients.

Pain may be the earliest symptom in Fabry disease and presents with a distinct phenotype including triggerable pain attacks, evoked pain, pain crises, and chronic pain. Current pain questionnaires do not reflect the special phenotype of Fabry disease-associated pain, which hampers its systematic evaluation as the basis of correct diagnosis and effective treatment. A questionnaire specifically designed to assess Fabry disease-associated pain is thus urgently needed. At the Würzburg Fabry Center for Interdisciplinary Therapy (FAZIT), Germany, we developed and validated the first face-to-face Fabry Pain Questionnaire (FPQ) for adult patients. The initial version of the FPQ was tested in a pilot study with 20 consecutive Fabry disease patients. The performance of the revised FPQ was assessed in a first (n=56) and second (n=20) validation phase in consecutive Fabry disease patients. For this, patients were interviewed at baseline and 2 weeks later. We determined the test-retest reliability and validity of the FPQ in comparison to data obtained with the Neuropathic Pain Symptom Inventory. The FPQ contains 15 questions on the 4 pain phenotypes of Fabry disease (pain attacks, pain crises, evoked pain, chronic pain) in childhood and adulthood, on pain development during life with and without enzyme replacement therapy, and on everyday life impairment due to pain. This first disease-specific questionnaire is a valuable tool for baseline and follow-up assessment of pain in Fabry disease patients and may guide treatment in this distinct pain phenotype.