Study	Reason for exclusion
Bernard 1996	Wrong intervention: RCT comparing keto acid supplements with no supplements in participants on the same protein intake; patients only treated for three months
Bernhard 2001	Wrong intervention: RCT, randomised to keto acid supplements with participants maintaining the same protein diet
Choi 2012a	Wrong intervention: RCT comparing keto acid supplementation with no supplements in participants on the same low protein diets
Coresh 1994	Wrong intervention: RCT, participants randomised to keto acid supplements
Di Iorio 2009a	Wrong duration of follow‐up: cross‐over study comparing very low protein diet supplemented with keto acids with low protein diet; follow‐up for only 6 months in each part of study
Di Iorio 2012a	Wrong duration of follow‐up: cross‐over study comparing very low protein diet supplemented with keto acids with low protein diet; each intervention for one week only
DODE Study 2000	Wrong intervention: RCT, participants randomised to diet or dialysis
El Nahas 1987	Wrong intervention: RCT comparing different distribution through day of protein intake; protein intake in both groups the same
ERIKA Study 2007	Wrong population. included 35% diabetic patients
Garibotti 2018	Wrong duration: 24 weeks duration only
Garini 1992	Wrong intervention: RCT comparing very low protein intake (0.4 g/kg/d) + keto acids/essential amino acids (0.2 g/kg/d) with low protein intake (0.6 g/kg/d) but nitrogen intake did not differ between groups
Hecking 1980	Wrong duration: six weeks duration only
Herselman 1995	Wrong duration: RCT comparing very low protein diet with low protein diet; follow‐up only for 9 months
Ideura 2003	Wrong duration: RCT comparing different protein intakes but duration of follow up is uncertain
IRCCA Study 1990	Wrong intervention: RCT, randomised to keto acid supplements
Kopple 1982	Wrong duration: RCT comparing low with very low protein diet but follow up averaged only 12 weeks
Laville 1994	Wrong duration: RCT comparing low protein with normal protein diet but follow‐up for only 6 months
Lim 2000	Wrong duration: six months duration only
Maksic 2004	Wrong duration: RCT, six months duration
Prakash 2004	Wrong duration: less than 12 months duration; compared low protein with very low protein diet supplemented with keto‐analogues
Ren 2002	Wrong intervention: RCT comparing same low protein diet (0.5 to 0.6 g/kg/d) in both groups with keto acids added in one group
Rosenberg 1987	Wrong duration: cross‐over study with participants only studied for 11 days in each phase
Sanchez 2010	Wrong intervention and duration: RCT comparing low protein diet with diet in which some foods were replaced by low protein foods; follow‐up only 6 months
Teplan 2003	Wrong intervention: RCT comparing additional keto acids with no addition in participants on a low protein diet and EPO
Teplan 2006	Wrong intervention: RCT comparing low protein diet (0.6 g/kg/d) + keto‐analogues with low protein diet + placebo in obese participants with CKD
Ursea 2002	Wrong duration: RCT comparing 0.3 g/kg of protein (with keto‐analogues) versus 0.6 g/kg but follow up only to 6 months
Vujic 1987	Wrong intervention: RCT but no separation in reported nitrogen intake as low protein diet supplemented by amino acids equivalent to 0.2 g/kg/d of protein
Zhang 2015	Wrong duration: RCT comparing low protein with normal protein diet but outcome data only available to 6 months
Zhang 2016b	Wrong population: patients with steroid resistant nephrotic syndrome and minor reduction in GFR

CKD ‐ chronic kidney disease; EPO ‐ erythropoietin; GFR ‐ glomerular filtration rate; RCT ‐ randomised controlled trial