Physical fitness in adolescent patients with familial Mediterranean fever

Introduction: Familial Mediterranean fever (FMF) is the most frequent monogenic auto-inflammatory disease worldwide responsible for episodes of fever, serositis and musculoskeletal symptoms. Inflammatory attacks are responsible for sedentary behavior and FMF patients may be at increased cardiovascular risk. Cardiorespiratory Fitness (CRF) and physical capacities during adolescence are associated with cardiovascular mortality in adulthood. In this study, we aimed to describe the physical fitness of FMF adolescents. Methods: A monocentric retrospective study at the Versailles Hospital between January 2020 and June 2023. All FMF patients over 14-year-old who had completed a routine physical test were included. Clinical and physical data including results of the 6-minute walking test, timed unipedal stance test, Ruffier-Dickson index, 30-seconds chair-stand test and sit-and-reach test were extracted from medical records. Results were compared with previously published normative reference values and criterion-referenced standards for healthy subjects. Results: Eighteen FMF patients (12 girls, 6 boys) were included. The median age was 16 years old [14-18]. Clinical history included joint symptoms (n = 11), chest pleuritis (n = 8), and leg pain (n = 11). Estimated VO2max was below the recommended thresholds in 13 patients, which predicts cardiovascular risk. Cardiovascular adaptation was poor in 11 patients. Low VO2max was associated with CRP > 5 mg/l on test day and history of joint symptoms. Conclusion: FMF patients displayed altered physical capacities compared to normative values of healthy subjects. History of musculoskeletal pain, systemic inflammation and sedentary behavior may participate in impaired physical abilities and promote cardiovascular diseases in adulthood. Specific exercise programs could benefit patients for disease control and cardiovascular risk reduction.