Table 2.

NewcastleOttawa Scale assessment of pooled studies

Study	Selection				Comparability	Outcomes			Total
	Representativeness of exposed cohort	Selection of nonexposed cohort	Ascertainment of exposure	Outcome not present at the start of the study		Assessment of outcomes	Length of follow-up	Adequacy of follow-up
Osman/2009	*	*	*	*		*	*	*	7
Bull/2010	*	*	*	*		*	*	*	7
Fichet/2012	*	*	*	*		*	*	*	7
Legras/2015	*	*	*	*		*	*	*	7
Lazzeri/2016	*	*	*	*		*	*	*	7
Mekontso Dessap/2016	*	*	*	*	**	*	*	*	9
See/2017	*	*	*	*	**	*	*	*	9
Bonizzoli/2018	*	*	*	*		*	*	*	7
Zeiton/2018	*	*	*	*		*	*	*	7

Although multivariate analysis was performed, it was not for 28-day mortality (it was for 90-day mortality)