Erythropoietin therapy after out-of-hospital cardiac arrest: A systematic review and meta-analysis

Table 2 Assessment of quality for the included studies

Newcastle-Ottawa scale for bias assessment for case-controlled studies
Newcastle-Ottawa scale for bias assessment	Cariou et al[9], 2008	Grmec et al[10], 2009
Selection	3	2
Comparability	2	2
Exposure	3	3
Cochrane Risk of Bias tool for the Randomized controlled study (Cariou et al[11])
Entry	Judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “Patients were randomly assigned in a 1:1 ratio to the intervention or the control group”
Allocation concealment (selection bias)	Low risk	Quote: “Randomization was performed centrally with the use of a computer-generated assignment sequence Intervention assignments were made in permuted blocks of varying size and were stratified according to site”
Blinding of participants and personnel (performance bias)	High risk	Comment: Probably done
		Quote: “Single-blinded”; “physicians performing neurological follow-up and final outcome measurement, as well as study administrators and statisticians, were unaware of the intervention assignments”
		Comment: Probably done. However, only single blinding performed
Blinding of outcome assessment (detection bias) (patient-reported outcomes)	Low risk	Quote: “Single-blinded”
		Comment: Probably done
Blinding of outcome assessment (detection bias) (mortality)	Low risk	Obtained from medical records; Quote “CPC was assessed by face-to-face contact with patients still hospitalized, and through phone interviews in discharged patients using a standardized protocol”
		Review authors do not believe this will introduce bias
Incomplete outcome data addressed (attrition bias) (Longer-term outcomes, > 6 wk)	Low risk	60 d: 1/234 missing from intervention group (“lost to follow-up”); 0/242 missing from control group
Selective reporting (reporting bias)	Low risk	A single scale to assess neurological outcomes was used and reported (CPC score)