Meloni 2004.

Study characteristics
Methods	Study type: parallel RCT Duration of study duration: 1 January 2001 to 31 December 2001 Study follow‐up period: 1 year
Participants	Country: Italy Setting: single centre Patients with CKD; GFR < 60 mL/min/1.73 m2 Number: low protein diet group (44); normal protein diet group (45) Mean age ± SD (years): low protein diet group (60.2 ± 13.5); normal protein diet group (64.2 ± 13.4) Sex M/F: 46/43 Exclusion criteria: systemic disease chronic infection; cancer; receiving corticosteroids/immunosuppressive agents
Interventions	Low protein diet group Prescribed protein intake: 0.6 g protein/kg/day Calculated protein intake at 1 year: 0.67± 0.21 g/kg/day Normal protein diet group Prescribed protein diet: free protein diet Calculated protein intake at 1 year: 1.54 ± 0.39 g/kg/day Co‐interventions Treatment for hypertension, hyperlipidaemia, anaemia
Outcomes	GFR at 12 months measured by Cr‐51 EDTA clearance Body weight BMI
Notes	Average GFR 46.8 ± 5.8 mL/min/1.73 m2 of all included participants Study separately randomised 80 participants with DM into low and normal protein groups Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Simple randomisation using dedicated software generating casual numbers to assign participants to treatment groups and remaining participants were placed in control group"
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded and lack of blinding may influence patient management
Blinding of outcome assessment (detection bias): End or change in GFR End of change in GFR	Low risk	Primary outcome of GFR was measured by EDTA clearance and unlikely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias): Need to start dialysis Need to start dialysis	Unclear risk	No information provided as "need to start dialysis" was not a reported outcome
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants appear to have completed follow up
Selective reporting (reporting bias)	High risk	Did not report on deaths or ESKD
Other bias	Unclear risk	Insufficient information to permit judgement