Study of the Efficacy and Safety of Nicotinamide in Patients With Liver Fibrosis (NICOFIB)

Patients with a Fibroscan \> 8 kPa will be offered to participate in this study. Participants will receive either placebo or a NAM dose adjusted to body weight. The duration of the treatment is 12 months. Participants will be subjected to a total of 5 follow-up and/or control visits: Visit 1 * Physical examination(weight, height, BMI, waist circumference, neck circumference, blood pressure, and heart rate). * Assessment of muscle status and risk of sarcopenia: grip strength, chair test. * Basal electrocardiogram. * Blood analysis. * Bioelectrical impedance analysis. * Nuclear magnetic resonance. * Thermographic image. * Food questionnaire (PREDIMED). * International Physical Activity Questionnaire (IPAQ). * Collection of blood, urine, and feces samples for storage in the biobank. Visit 2. Control visit (time month 1) * Monitoring of adverse events (AE) and adverse reactions (AR). * Electrocardiogram. * Control blood analysis: sodium, potassium, liver biochemistry (AST, ALT, bilirubin, GGT, FA), renal function (urea, creatinine, estimated glomerular filtration), and coagulation tests. * Physical examination and measurement of vital signs. Visit 3. Follow-up visit (time month 3) * Monitoring of AE and AR. * Drug adherence questionnaire. * Electrocardiogram. * Blood analysis. * Physical examination (weight, BMI, waist circumference, neck circumference, blood pressure, and heart rate). * Collection of blood, urine, and feces samples for biobank. * Collection of concomitant medication. * Adherence to study treatment and dietary recommendations. Visit 4. Follow-up visit (time month 6) * Monitoring of AE and AR. * Drug adherence questionnaire. * Electrocardiogram. * Blood analysis. * Physical examination (weight, BMI, waist circumference, neck circumference, blood pressure, and heart rate). * Collection of blood, urine, and feces samples for biobank. * Collection of concomitant medication. * Adherence to study treatment and dietary recommendations. Visit 5. Control visit (time month 9). * Monitoring of AE and AR. * Drug adherence questionnaire. * Electrocardiogram. * Control blood analysis. * Physical examination. * Collection of concomitant medication. Visit 6. Final exploration (time month 12) * Monitoring of AE and AR. * Drug adherence questionnaire. * Food questionnaire (PREDIMED). * Physical Activity Questionnaire (IPAQ). * Physical examination and measurement of vital signs (weight, BMI, waist circumference, neck circumference, blood pressure, and heart rate). * Assessment of muscle status and risk of sarcopenia: FPM, chair test. * Electrocardiogram. * Blood analysis. * Measurement of NAM and derived metabolites in serum and urine. * Nuclear magnetic resonance. * Bioimpedance. * Thermographic image. * Fibroscan® with CAP. * Collection of blood, urine, and feces samples for biobank The safety of the participants will be assessed using a record of the AEs and ARs that could arise and their annotation in the EDC, as well as a regular evaluation of liver, kidney, and heart function at baseline, 1, 3, 6, 9 and 12 months