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Table 1 Assessment of Risk of Bias of Randomized Controlled Trials

From: Erythropoiesis stimulating agents and reno-protection: a meta-analysis

Reference Trial features Randomized sequence Allocation concealment Blinding of outcome assessors ITT analysis Reports on Lost patients All patients treated in assigned group
Dardashti 2014 [24] AKI: DB, SS Low risk: patients were randomly allocated. Low risk: sequentially numbered, sealed, & opaque envelopes. Independent nurses prepared the study drug & syringes were delivered blinded High risk High risk: 5 patients that received study drug were discontinued and excluded from analysis Low risk: lost patients reported Low risk: all patients treated
deSeigneux 2012 [76] AKI: DB, SS Low risk: a randomization code was generated by computer Low risk: envelopes with allocation were prepared by the quality of care unit. A nurse opened the envelopes and prepared the syringes for injection. Investigators and patients were blinded to the treatment High risk Low risk: AKI data on all patients Low risk: lost patients reported Low risk: all patients treated
Endre 2010 [26] AKI: DB, MS (2 centers) Low risk: allocation by a predefined computer-generated randomization sequence Low risk: concealment was by a pharmacist; pairs of identical syringes. Patients, all medical staff, & investigators were blinded to treatment Low risk: Data Safety Monitoring Board with unmasking followed recording of the final AEs of the patient last enrolled Low risk Low risk: lost patients reported Low risk: but 1 patient withdrew
Kim 2013 [27] AKI: DB, SS Low risk: computer-generated random code Low risk: medications were prepared by a nurse who knew the patient’s group assignment but was not involved in the study Unclear risk Low risk: No dropouts Low risk: lost patients reported Low risk: all patients treated
Oh 2012 [16] AKI: DB, SS Low risk: A randomization code list with a block size of two was generated. Treatments were allocated to patients through the Internet in accordance with the predefined randomization list Low risk: a research coordinator performed randomization and prepared the study drugs Unclear risk Low risk Low risk: all patients completed the trial Low risk: all patients completed the trial
Tasanarong 2013 [28] AKI: DB, SS Low risk: treatment assignment by blocked randomization. Sealed envelopes containing the allocation group were opened by nurses who did not participate in the study Low risk: treatments were blindly given to the research coordinator. Patients and investigators were blinded to group assignment. Pairs of identical syringes containing either rHuEPO or saline were prepared High risk Low risk: No dropouts Low risk: no dropouts Low risk: no dropouts
Yoo 2011 [29] AKI: OL(single blinded), SS Low risk: patients were allocated by computer-generated random numbers Unclear risk: medications were prepared and administered by a ward physician recognizing the patient’s group but not involved in the current study, the surgeon and anesthesiologist involved were blinded Low risk: the surgeon and anesthesiologist involved in the study and patient management were blinded to the patients’ groups until the end of the study Low risk: complete data sets from the 74 patients were analyzed without any missing data Low risk: no dropouts Low risk: complete data sets from the 74 patients were analyzed without any missing data
Aydin 2012 [31] Transplant: DB, SS Low risk: Patients were randomized by an independent hospital pharmacist. The randomization allocation sequence was generated by a random-number table Low risk: patients, physicians, data managers and investigators were kept blinded throughout the study Low risk: data managers and investigators were kept blinded throughout the study Low risk: No dropouts Low risk: No dropouts Low risk: No dropouts
Coupes 2015 [30] Transplant: DB, SS Low risk: patients were randomly assigned by the trial pharmacy by computer Low risk: all study participants and the study team were blinded to the trial drug Unclear risk Low risk: 1 patient withdrew but was included in the analysis Low risk: lost patients reported Low risk
Hafer 2012 [32] Transplant: DB, SS Unclear risk: randomization methodology not disclosed Low risk: vials containing ESA and placebo had identical appearance Unclear risk Low risk for DGF. High risk for graft loss (3 patients died 1 in ESA group and 2 in placebo group) Low risk: lost patients reported High risk: 2 untreated patients (not included in analysis) and 3 patients died
Martinez 2010 [33] Transplant: OL, MC Unclear risk: randomization method not disclosed High risk: comparator arm was untreated Low risk: Blinded evaluation of end-points Unclear risk: 1 died in ESA group Low risk: lost patients reported Low risk
Sureshkumar 2012 [34] Transplant: DB, SS Low risk: the hospital pharmacy created a schedule using random assignments to a series of patient study numbers Low risk: ESA and placebo were both 1 ml syringes. The medications were administered in a double-blinded manner Unclear risk Low risk Low risk: no dropouts Low risk
Van Biesen 2005 [35] Transplant: OL, SS Unclear risk: randomization method not disclosed High risk: open label High risk Unclear risk High risk Unclear risk
Van Loo 1996 [36] Transplant: OL, SS Unclear risk: randomization method not disclosed High risk: open label High risk Low risk: no deaths or withdrawals Low risk: no deaths or withdrawal Low risk: no deaths or withdrawals
Abraham 1990 [38] Anemia correction: DB then OL, Anemia correction: SS Unclear risk: randomization method not disclosed Unclear risk: unspecified High risk Low risk: no dropouts Low risk: no dropouts Low risk
Clyne 1992 [39] Anemia correction: OL, 2 center Unclear risk High risk High risk Low risk: for RRT Low risk: lost patients reported Low risk
Kleinman 1989 [40] Anemia correction: DB, MC Unclear risk: randomization method not specified Unclear risk: unspecified High risk Unclear risk: no dropouts reported Unclear risk: no dropouts reported Low risk
Kuriyama 1997 [41] Anemia correction: OL, SS Unclear risk High risk High risk Low risk Low risk: lost patients reported Low risk
Lim 1989 [42] Anemia correction: DB, SS Low risk: randomization by third party Unclear risk Unclear risk High risk Low risk: lost patients reported Low risk
Lim 1990 [43] Anemia correction: OL, SS Unclear risk High risk High risk Low risk: no dropouts Low risk: no dropouts Low risk
Revicki 1995 [18] Anemia correction: OL, MC High risk High risk High risk Low risk: for RRT endpoint Low risk: lost patients reported Unclear risk
Cianciaruso 2008 [45] Anemia correction: OL, MC Low risk: randomization by computer at a separate site Low risk: allocation was concealed from investigators, sequences were sequentially numbered in opaque envelopes opened in sequence High risk Low risk Low risk: lost patient reports High risk: 1 patient in the treatment group did not receive ESA, study terminated early
Gouva 2004 [47] Anemia correction: OL, MC Low risk: computer generated sequence Unclear risk High risk Low risk Low risk: lost patients reported High risk: study prematurely terminated
Levin 2005 [48] Anemia correction: OL, MC Low risk: computer generated sequence Low risk: allocation was in sealed sequentially numbered opaque envelopes. Designated personnel opened the next number in sequence High risk Low risk Low risk: lost patient reports High risk: only 77/85 in the high Hb group received ESA
MacDougall 2007 [49] Anemia correction: OL, MC Low risk: randomized using central randomization procedures (ClinPhone) Unclear risk High risk Low risk Low risk: lost patients reported High risk: patients in the high Hb group received ESA on day 1 but study was prematurely terminated
Pfeffer 2009 [50] Anemia correction: DB, MC Low risk: DB, and patients were randomly assigned with the use of a computer-generated, permuted-block design Unclear risk High risk High risk: 9 patients were excluded prior to unblinding Low risk: lost patient reports High risk: 93.9% of the patients in the darbepoetin alfa group were receiving the assigned treatment at 6 months”
Ritz 2007 [51] Anemia correction: OL, MC Low risk: randomization was performed centrally into treatment groups by using a block-size randomization procedure stratified by country Unclear risk High risk Low risk Low risk: lost patient reports Unclear risk: patients in group 1 were started immediately ESA but 3 patients withdrew
Roger 2004 [52] Anemia correction: OL, MC Low risk: patients were randomized according to computer-generated stratification tables Low risk: order concealment was maintained until the intervention was assigned High risk Low risk Low risk: lost patient reports Low risk
Rossert 2006 [53] Anemia correction: OL, MC Low risk: patients were randomized according to computer-generated stratification schedule Unclear risk High risk Low risk Low risk: lost patient reports High risk: study was terminated prematurely. Many subjects did not enter maintenance or withdrew
Villar 2011 [55] Anemia correction: OL, MC Low risk: block-size randomization was used Unclear risk High risk Low risk Low risk: lost patients reported Unclear risk: most patients likely received ESA but 6 patients died or withdrew
Akizawa 2011 [44] Anemia correction: OL, MC Low risk: patients were assigned by a computer according to a minimization method Unclear risk High risk Low risk Low risk: lost patients reported High risk: after 1 administration, 43 withdrew.
Drueke 2006 [46] Anemia correction: OL, MC Low risk: randomization was performed centrally with the use of a dynamic randomization method Unclear risk High risk Low risk Low risk: lost patients reported High risk: 75 in the high Hb group withdrew
Singh 2006 [54] Anemia correction: OL, MC Low risk: patients were assigned by computer-generated per-muted-block randomization Unclear risk High risk Low risk Low risk: lost patients reported High risk: study was terminated early at the second interim analysis because power to demonstrate benefit was less than 5%, and there was a high withdrawal rate
  1. *RCT-randomized controlled trial, DB Double blind, OL Open label, MC Multicenter, SC Single center