Wang 2017

Methods	Study design: parallel RCT Duration of study: June 2014 to June 2015 Duration of follow‐up: 6 months
Participants	Country: China Setting: single centre Donor characteristics Mean age ± SD: 48.2 ± 12.6 years Number of DCD: 48 sex (M/F): 18/6 Inclusion criteria: not reported Exclusion criteria: not reported Recipient characteristics Inclusion criteria: not reported Exclusion criteria: not reported Sex (M/F): MP group (15/9); SCS group (18/6) Mean age ± SD (years): MP group (44.6 ± 8.1); SCS group 940.2 ± 6.2)
Interventions	Machine perfusion Lifeport (ORS) system using KPS‐1 at a constant pressure of 30 mmHg Static cold storage Solution not reported Mean CIT Poorly reported. CIT in the SCS group ranged from 1‐8 hours, and mean CIT in the MP group was 5.8 ± 2.8 hours
Outcomes	DGF is listed as the primary outcome, a non‐standard definition was used ("DGF was defined as one of the following: postoperative anuria or oliguria and the need to reinitiate hemodialysis in the first week after surgery; or hemodialysis was not reinitiated, but SCr was greater than 400 µmol/L at 7 days after surgery") Acute rejection "time‐zero biopsies" Length of hospital stay was not listed as an outcome, but was reported in the results
Notes	One kidney from each pair assigned to MP and the other to SCS 48 kidneys from 24 donors. All were DCD donors The authors concluded that HMP was superior to SCS, as it reduces the incidence of DGF. This paired study was not properly randomised and risk of bias was felt to be unacceptable given the following: one kidney from each pair was randomised to SCS and one to HMP but surgeons could switch kidneys between groups if they felt that aberrant vascular anatomy would interfere with HMP. No data was given on how many pairs of kidneys were switched between preservation methods, and no intention to treat analysis was performed. In addition, there was incomplete information on the SCS group; a mean CIT was not given and the type of solution used was not reported. A significant difference in CIT could have been present. Finally, a non‐standard definition for DGF was used; requirement for dialysis in the first week or SCr greater than 400µmol/L at day 7 post surgery. No justification was given for this definition. Only DGF using their definition was reported as an outcome, and no information was given as to how many kidneys required dialysis. This raises the possibility of selective reporting bias Funding source: " This study was supported by the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (ZYLX201408), the National Natural Science Foundation of China (No. 81270837), the Beijing Natural Science Foundation (No. 7132107), and Foundation Clinical Research of capital Medical University(No. 1140170035)"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	There was no information on how kidneys were randomised. Furthermore, surgeons could swap kidneys from the HMP to the SCS if they felt the aortic patch was too small or if the anatomy of the renal arteries was non‐standard. No intention to treat analysis was applied. No indication was given as to how many kidneys were swapped between groups
Allocation concealment (selection bias)	High risk	Allocation concealment was not possible with the study design, kidneys were moved between groups without intention to treat analysis
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding and no reporting of CIT. Therefore one group may have routinely been transplanted first, adding bias to the results
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding of DGF data. No information is given as to whether the assessors of "acute rejection" or "time zero biopsies" were blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	For the outcome "time‐zero biopsies" no data is given for the groups as a whole. Only H+E stains and electron microscopy from a single pair of kidneys are presented
Selective reporting (reporting bias)	High risk	A non‐standard definition for DGF was used as the primary outcome of the study. The number of participants requiring dialysis in the first week post‐transplant (the standard definition for DGF) was not reported. No specific outcome was associated with the "time‐zero biopsies". In the results section some features of H+E stains, and electron microscopy were reported, leaving a high risk of selection bias. Furthermore, only H+E stains and electron microscopy from a single pair of kidneys are presented
Other bias	High risk	Although acute rejection is reported as an outcome, it is not stated whether this is biopsy proven rejection or clinical rejection. It is also not stated over what time period acute rejection data was collected over