An adapted cardioprotective diet with or without phytosterol and/or krill oil supplement in familial hypercholesterolemia: A pilot study protocol

Summary: Background and aims: A healthy diet is one of the pillars of familial hypercholesterolemia (FH) treatment. However, the best dietary pattern and indication for specific supplementation have not been established. Our aim is to conduct a pilot study to assess the effect of an adapted cardioprotective diet with or without phytosterol and/or krill oil supplement in participants with a probable or definitive diagnosis of FH, treated with moderate/high potency statins. Methods: A national, multicenter, factorial, and parallel placebo-controlled randomized clinical trial with a superiority design and 1:1:1:1 allocation rate will be conducted. The participants will undergo whole exome sequencing and be allocated into four treatment groups: 1) a cardioprotective diet adapted for FH (DICA-FH) + phytosterol placebo + krill oil placebo; 2) DICA-FH + phytosterol 2 g/day + krill oil placebo; 3) DICA-FH + phytosterol placebo + krill oil 2 g/day; or 4) DICA-FH + phytosterol 2 g/day + krill oil 2 g/day. The primary outcomes will be low-density lipoprotein (LDL)-cholesterol and lipoprotein (a) levels and adherence to treatment after a 120-day follow-up. LDL- and high-density lipoprotein (HDL)-cholesterol subclasses, untargeted lipidomics analysis, adverse events, and protocol implementation components will also be assessed. Results: A total of 58 participants were enrolled between May–August 2023. After the end of the follow-up period, the efficacy and feasibility results of this pilot study will form the basis of the design of a large-scale randomized clinical trial. Conclusions: This study's overall goal is to recommend dietary treatment strategies in the context of FH.