Effectiveness and health benefits of a nutritional, chronobiological and physical exercise primary care intervention in fibromyalgia and chronic fatigue syndrome: SYNCHRONIZE plus mixed-methods study protocol

Introduction:Chronic pain, fatigue and insomnia are classic symptoms of fibromyalgia (FM) and chronic fatigue syndrome (CFS) and seriously affect quality of life. Nutrition and chronobiology are often overlooked in multicomponent approach despite their potential. This study aims to evaluate the effectiveness of a multidisciplinary group intervention based on nutrition, chronobiology, and physical exercise in the improvement of lifestyle and quality of life in FM and CFS. Methods:Mixed-methods study based on a randomized clinical trial and qualitative analysis with a descriptive phenomenological approach. The study will be conducted in primary care in Catalonia. The control group will follow the usual clinical practice and the intervention group the usual practice plus the studied intervention (12 hours over 4 days). The intervention based on nutrition, chronobiology and physical exercise will be designed considering participants' opinions as collected in 4 focus groups. To evaluate effectiveness, EuroQol-5D, multidimensional fatigue inventory, VAS pain, Pittsburgh Sleep Quality Index, erMEDAS-17, biological rhythms interview of assessment in neuropsychiatry, REGICOR-Short, FIQR and Hospital Anxiety and Depression Scale questionnaires will be collected at baseline, and at 1, 3, 6, and 12 months post-intervention. Food intake, body composition, resistance and, strength will also be evaluated. The effect size will be calculated using Cohen d and logistic regression models will be used to quantify the impact of the intervention by adjusting for different variables. Discussion:It expected that the intervention will improve the patients' quality of life, fatigue, pain and insomnia, as well as food and physical exercise habits, providing effectiveness evidence of a new therapy in addressing these syndromes in Primary Heath Care. Improvements in the quality of life will have a positive socioeconomic impact by reducing health expenditure on recurrent medical consultation, medication, complementary medical tests, etc and favor the maintenance of an active working life and productivity.