Muscle-Saving supplement tested in kidney patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Men or women * Older than 18 years of age * Stage 4 or 5 CKD (eGFR with CKD-EPI 2009 creatinine equation \< 30 mL/min/m2), whitout renal replacement therapy or kidney transplantation * Protein intake 0.6-0.8 g/kg/d (estimated with Moroni formula) * Social security cover * Written informed consent Exclusion Criteria: * Hospitalization in the past 3 months * Corticosteroids (\> 7.5 mg/d), cytotoxic or immunosuppressive drugs * Severe symptomatic heart (NYHA 3 or 4) or liver failure (Child Pugh B or C) * Respiratory failure requiring oxygenotherapy * Ongoing infection, autoimmune disease or cancer * Pregnant (e.g., positive human chorionic gonadotrophin \[HCG\] test) or lactating patients * Risk of pregnancy: any woman who does not fulfil one of the following criteria: * post-menopausal (aged \> 45 years with amenorrhea for more than 2 years, or of any age with amenorrhea for more than 6 months and an FSH level \> 40 mUI / mL) * permanent sterilisation (e.g., occlusion/bilateral ligature of the fallopian tubes, hysterectomy, bilateral salpingectomy, bilateral ovariectomy) or constitutional sterility * of childbearing age and using an efficient method of contraception, begun at least 28 days before inclusion. Efficient contraception methods are: oral, injectable or implantable hormonal methods intra-uterine devices sterilisation of the male partner if he is the sole partner abstinence, if compatible with the preferred and usual lifestyle of the individual NB: if child bearing potential changes during the study, the woman must start taking one of the efficient methods of contraception as described above. * Patients with psychiatric or cognitive disorders rendering them unable to give written informed consent * Patients unwilling to participate in the study * Hypersensitivity to the active substances in Ketosteril® * Hypercalcaemia * Hypophosphatemia * Patient under a legal protection (curatorship or tutorship)