Daugirdas 1985.

Methods	Study design: cross‐over RCT Duration of study: not reported Duration of follow‐up: 4 weeks
Participants	Country: USA Setting: single centre Prevalent (on HD for > 1 year) HD patients (clinical characteristics not reported other than being prone to intradialytic hypotension and cramps and not clinically fluid overloaded) Number: 10 patients allocated to control and then treatment, or treatment and then control, attrition of 3 patients for hospitalisation due to treatment‐unrelated illness, resulting in 7 for final analysis Mean age ± SD (years): not reported Sex (M/F): not reported Mean time of dialysis: not reported Exclusion criteria: not reported
Interventions	HD regimen 3 times/week, 4 hours/session Low‐flux 1.0 m2 PAN plate dialysers Acetate‐buffered dialysate QB 250 mL/min, QD 500 mL/min, URR and Kt/V not reported Treatment group 1 Dialysate [Na+]: 135 mM Treatment group 2 Dialysate [Na+]: 143 mM Treatment group 3 Profiled dialysate [Na+] from 160 to 133 mM (average dialysate [Na+] for session = ??, data not used) Duration 4 weeks for each (only the last 3 weeks of any given 4‐week block was analysed) (63 HD sessions in control group, 63 in treatment group)
Outcomes	Outcomes were assessed over the entire period of treatment/observation Intradialytic hypotension ‐ "15% fall in mean arterial BP" Predialysis SBP and DBP Intradialytic SBP and DBP Intradialytic cramps IDWG Thirst (VAS) Predialysis serum [Na+] Weakness score
Notes	Funding source: not reported Extra information was requested from the authors but the original study data have been lost Weakness scores were not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation clearly stated in published article, but not mechanism of randomisation
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double blinding clearly stated in published article and confirmed by the lead author
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	3 patient dropouts "were judged to be treatment‐unrelated, and accordingly, their data were excluded from analysis". The study is not analysed as intention to treat, and data from those who dropped out is omitted from analysis. Although the reasons for dropout do not appear to be related to the treatment, there is still risk of attrition bias. In addition, this large number of dropouts may have affected balance of patient characteristics by arm. The groups appeared balanced on measured confounders in table 1, but an effect of these dropouts on unmeasured confounders is unknown
Selective reporting (reporting bias)	Low risk	The study appears to be free of reporting bias
Other bias	High risk	Obsolete dialysis practice patterns (acetate buffered dialysate, parallel plate dialysers), with a patient sample that is not reflective of modern populations. Risk of poor external validity (indirectness)