Bouman 2002.

Study characteristics
Methods	Study design: parallel RCT Duration of study: May 1998 to March 2000 Duration of follow‐up: 28 days
Participants	Setting: multicentre (2 centres) Country: The Netherlands Patients with circulatory and respiratory insufficiency and early AKI who need CKRT; CrCl < 20 mL/min, and oliguria < 180 mL/6 hours despite fluid resuscitation; circulatory support and furosemide; early timing: < 12 hours inclusion; late timing: BUN > 40 mmol/L or severe pulmonary oedema Number: intervention group 1 (35); intervention group 2 (35), control group (36) Mean age ± SD (years): intervention group 1 (68 ± 13); intervention group 2 (70 ± 10); control group (67 ± 13) Sex (M/F): intervention group 1 (21/14); intervention group 2 (20/15); control group (23/13) Exclusion criteria: pre‐existing kidney disease with CrCl < 30 mL/min; AKI caused by permanent occlusion or surgical lesion of the renal artery; GN, interstitial nephritis, or vasculitis; postrenal obstruction; CHILD class C liver cirrhosis; AIDS with a CD4 count < 0.05 x 109/L; non‐witnessed arrest with Glasgow Coma Score < 5; haematological malignancy with neutrophils < 0.05 x 109/L; no haemofiltration machine free for use at time of inclusion arrest with Glasgow Coma Score < 5; haematological malignancy with neutrophils < 0.05 x 109/L; no haemofiltration machine free for use at time of inclusion
Interventions	KRT modality CVVHF Haemofilter: cellulose triacetate hollow‐fibre Replacement fluid: post‐dilution mode with bicarbonate solution Anticoagulation: heparin or nadroparin Intervention group 1 Early + high volume HF: intervention started within 12 hours after time of inclusion, and the UF flow rate was high (prescribed dose > 72 L/day and delivered dose 48.2 mL/kg/hours) Intervention group 2 Early + low‐volume HF: intervention started within 12 hours after time of inclusion, and the UF flow rate was low (prescribed dose 24 to 36 L/day and 19 to 20 mL/kg/hour) Control group Late + low‐volume HF: intervention started when the patients fulfilled the conventional criteria for KRT Urea level > 40 nmol/L, potassium > 6.5 mmol/L or severe pulmonary oedema, and the UF flow rate was 24 to 36 L/day and the delivered dose 19 to 20 mL/kg/hour Co‐interventions Not reported
Outcomes	Primary outcomes Death at day 28 Recovery of kidney function Secondary outcomes ICU survival Hospital survival Duration of mechanical ventilation Length of ICU stay Length of hospitalisation
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Patients randomly assigned to one of the two treatment groups using computer‐generated method
Allocation concealment (selection bias)	Low risk	Treatment assignments were kept in numbered, sealed opaque envelopes that were opened at the time of enrolment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement (for kidney recovery was unclear risk but for death was low risk)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The outcome measurement is not likely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Complete outcome data were reported
Selective reporting (reporting bias)	Low risk	The study reported death, kidney function recovery and adverse events
Other bias	Unclear risk	Insufficient information to permit judgement