Teplan 1998.

Study characteristics
Methods	Study design: parallel RCT Duration of study: not reported Study follow‐up period: 3 years
Participants	Country: Czech Republic Setting: outpatient Patients with CKD Number: very low protein diet (35); low protein diet (38); restricted protein diet (32) Age range: 26 to 78 years Sex (M/F): 50/55 Exclusion criteria: diabetic kidney disease; failure to co‐operate; compliance ≤ 50%; severe associated disease (cancer, severe forms of atherosclerosis, chronic infection, immunosuppression)
Interventions	Very low protein diet Prescribed protein diet: 0.4 g/kg/day + keto amino acids Low protein diet Prescribed protein diet: 0.6 g/kg/day Restricted protein diet Prescribed protein diet: 0.8 to 1.0 g/kg/day Co‐interventions Hypertension treated with low dose ACEi and CCB
Outcomes	Metabolic status Kidney function (SCr, urea, proteinuria)
Notes	Abstract‐only publication; no full text publication identified Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study was described as randomised, method of randomisation was not reported
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Blinding of outcome assessment (detection bias): End or change in GFR End of change in GFR	Unclear risk	Insufficient information to permit judgement
Blinding of outcome assessment (detection bias): Need to start dialysis Need to start dialysis	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Selective reporting (reporting bias)	High risk	No extractable data; no full‐text publication identified
Other bias	Unclear risk	Insufficient information to permit judgement