Table 2.

Risk of bias (using the RoB2 tool [13])

Study	Randomisation process	Deviations from the intended interventions	Missing outcome data	Measurement of the outcome	Selection of the reported result	Overall rating
Pedegana et al. 1977 [15]	-	!	+	-	!	-
Van Arsdalen et al. 1983 [16]	+	-	+	-	!	-
Bucci et al. 1989 [17]	+	+	+	-	!	-
Ryan 2002 [19]	+	+	+	+	+	+
Silbersack et al. 2004 [20]	+	!	+	+	+	!
Chin et al. 2009 [21]	!	!	+	+	!	!
Turpie et al. 1989 [28]	+	+	+	-	+	-
Goldhaber et al. 1995 [27]	!	!	+	!	+	!
Gao et al. 2012 [23]	+	-	+	-	-	-
Prell et al. 2018 [25]	!	+	-	+	+	!
Sang et al. 2018 [26]	!	!	+	!	+	!
Lobastov et al. 2021 [24]	-	-	!	+	+	-

‘+’ Low risk; ‘!’ Some concerns; ‘-’ High risk