Santoro 1999.

Methods	Study time frame: March 1998 to December 2006 Study design: parallel RCT Duration of follow‐up: 4 years
Participants	Country: European Setting: multi‐centre (92) Incident critically ill HD patients, defined as one of the following: elderly (> 60 years); hypotension prone (≥ 5 hypotensive episodes/month); diabetic; CV instability (defined as a frequency of hypotensive episodes in more than 20% of dialysis sessions, or independently of frequency, if hypotension is accompanied by angina or major arrhythmia's) Mean time on dialysis: 6 to 8 months Number: treatment group (177); control group (194) Mean age ± SD (years): treatment group (66.9 ± 8.8); control group (67.1 ± 8.8) Sex (M/F): treatment group (106/71); control group (112/82) Exclusion criteria: older than 78 years; active neoplasia; severe cardiopathies (New York Heart Association [NYHA] Class III & Class IV); decompensating cirrhosis; poor vascular access function (pump flow < 200 mL/min or need for single needle system); previous continuous ambulatory peritoneal dialysis; treatment or kidney transplant; on waiting list for kidney transplant
Interventions	Treatment group AFB conducted using the AN69 membrane, infusing a 145‐167mM sodium bicarbonate solution usually warmed to a temperature similar to that of the dialysate, at a rate targeting for a post‐dialysis plasma bicarbonate levels of 27 to 30 mEq/L  Control group BD, low‐ or high‐flux synthetic membranes and dialysate with bicarbonate and acetate concentrations of 30 to 34 mM and 4 to 6 mM, respectively, were used according to each centre practice patterns
Outcomes	Intradialytic CV instability (hypo or hypertensive episodes) All‐cause mortality CV mortality Changes in predialysis BP Left ventricular mass Major CV event
Notes	Exclusions post randomisation but pre‐intervention: not stated Stop or end point/s: 39 dropouts in the AFB arm and 38 dropouts in the BD arm Additional data requested from authors: method of randomisation; details regarding blinding, allocation concealment Funding: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomisation was done centrally (with a computerized random‐number generator) using the balanced block randomisation technique with a 1:1 ratio, stratification according to the clinical centre concerned and a block size of eight"
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not stated, probably not done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated, probably not done
Incomplete outcome data (attrition bias) All outcomes	High risk	21% loss to follow‐up and dropouts censored at time of termination
Selective reporting (reporting bias)	High risk	Outcomes of interest are not reported
Other bias	High risk	Interventions not matched and patient baseline characteristics not matched