RESUMEN
BACKGROUND: Low-flow malformations (LFMs) are rare diseases with a significant impact on health-related quality of life (HRQoL), especially in children. No disease-specific questionnaire is available for children with LFMs. OBJECTIVE: To develop and validate a specific HRQoL questionnaire for children from 11 to 15 years old suffering from LFMs. METHODS: A preliminary questionnaire based on a verbatim from focus groups was created and sent to children from 11 to 15 years old suffering from LFMs, together with a dermatology-specific and a generic HRQoL questionnaire (cDLQI and EQ-5D-Y). RESULTS: A total of 75 from 201 included children responded to the questionnaires. The final version of the questionnaire (cLFM-QoL) included 15 questions and was not divisible into subscales. It demonstrated excellent internal consistency (cronbach 0.89), convergent validity and readability (SMOG 6.04). cLFM-QoL mean score (± SD) was 12.9/45 (8.03) for all grades of severity, for mild 8.22/45 (7.5), moderate 14.03/45 (8.35), severe 12.35/45 (6.59) or very severe patients 20.7/45 (3.39) (p 0.006). CONCLUSION: cLFM-QoL is a validated short and easy to use specific questionnaire with excellent psychometric capacities. It will be suitable for any children aged 11-15 with LFMs, in daily practice or clinical trials.