Ketoanalogue Supplementation for Muscle Protection in CKD 4 and 5 Patients With Moderately Low Protein Diet (KETO-PROT-ACTION)

Chronic kidney disease (CKD) complicates many pathologies and the rapid increase in its prevalence constitutes a major public health concern. Whatever the cause of kidney failure, high protein consumption is a factor of progression to end-stage kidney disease. A low-protein (0.6 g/kg/d) or a very low-protein (0.3 g/kg/d) diet associated with supplementation with amino acids and/or keto acid analogues (KA) slows down renal function deterioration and prolongs the time before dialysis start. Difficulties in strict protein restriction implementation limit its use to a minority of CKD patients and are difficult to implement in real life.

Recently KDOQI guidelines have recommended a dietary protein intake of 0.55 to 0.6 g/kg/d in CKD 3 to 5 non-diabetic patients "metabolically stable" and 0.6 to 0.8 g/kg/d in diabetic patients. However, the International Society of Renal Nutrition and Metabolism and the French guidelines about management of CKD propose to maintain a protein intake between 0.6 and 0.8 g/kg/d for all patients and as near as possible to 0.6 g/kg/d. This is because for a population, a mean value of 0.66 g/kg/d insures that 95% of patients are above 0.55 g/kg/d (the minimum requirement to avoid a negative nitrogen balance).

Experimental studies and few clinical studies suggest a protective effect of KA supplementation on uremic sarcopenia. Interestingly this effect is also observed in patients with a protein intake of 0.6 to 0.8 g/kg/d and with a dose of KA reduced by half compared to the dose used with VLPD. Moreover, in a preliminary study, we found a nephroprotective effect of KA (1 tablet/5kg body weight) in patients with an average dietary protein intake of 0.7 g/kg/d suggesting a specific effect of KA beyond protein restriction.

The hypothesis is therefore that KA treatment (1 tablet/10kg), together with a dietary protein intake between 0.6 and 0.8g/kg/d, prevent muscle mass loss in patients with stages 4 and 5 CKD. If these results were confirmed, this could expand the population that could benefit from KA supplementation.