Adult patients with new diagnosis or relapse of nephrotic syndrome and glomerular filtration rate of ≥ 30 mL/min/1.73m2 will be included in the study. Exclusion criteria will be a secondary cause of nephrotic syndrome, morbid obesity and severe diseases affecting nutritional status.~Participants will be randomly assigned to the intervention group (KA+MPD) or control group (MPD); randomization will be stratified by type of glomerular disease (podocytopathy or other type) and investigational site. The control group will follow the diet recommended in nephrotic syndrome - a medium protein diet (MPD) - under the care of a dietitian. Intervention group will receive Ketosteril (1 tablet for every 5 kg of ideal body weight) as an addition to the diet. All patients will also receive treatment for underlying glomerular disease in accordance with current guidelines and local practice.~The main objective is to assess the efficacy of Ketosteril as an add-on therapy in preventing the loss of lean tissue mass (LTM) over 6 months compared to a standard diet.~The additional aims include the assessment of muscle function parameters, nephrotic syndrome severity and laboratory indicators of catabolism.
The goal of this non-commercial clinical trial is to assess efficacy and safety of ketoanalogues of essential amino acids in the prevention of protein-energy wasting in nephrotic syndrome.