Table 2:

Methodologic quality assessment of included cohorts

Study	Defined sample^*	Representative sample^†	Follow-up rate > 80%^‡	Follow-up time^§	Prognosis^¶
Bakker et al. (10)	Yes	No	Yes	Yes	Yes
Bousema et al. (11)	Yes	No	Yes	Yes	Yes
Breen et al. (12)	Yes	No	No	No	No
Carey et al. (13) Sundararajan et al. (14)	Yes	Yes	Yes	Yes	Yes
Carey et al. (15)	Yes	Yes	No	Yes	Yes
Costa et al. (16)	Yes	Yes	Yes	Yes	Yes
Coste et al. (17)	Yes	Yes	Yes	Yes	Yes
Coste et al. (18)	Yes	Yes	Yes	Yes	Yes
Epping-Jordan et al. (19) Shaw et al. (20) Wahlgren et al. (21) Williams et al. (22)	Yes	Yes	Yes	Yes	Yes
Faber et al. (23)	Yes	Yes	Yes	Yes	Yes
Ferguson et al. (24), (25)	Yes	No	Yes	Yes	Yes
Gatchel et al. (26), (27)	Yes	No	No	Yes	No
Grotle et al. (2), (28)	Yes	No	Yes	Yes	Yes
Gurcay et al. (29)	Yes	Yes	Yes	Yes	Yes
Hasenbring et al. (30)	Yes	Yes	Yes	Yes	Yes
Hazard et al. (31) Reid et al. (32)	No	Yes	Yes	Yes	Yes
Heneweer et al. (33)	Yes	Yes	Yes	Yes	Yes
Henschke et al. (3)	Yes	Yes	Yes	Yes	Yes
Klenerman et al. (34)	Yes	No	No	Yes	Yes
Koleck et al. (35)	Yes	Yes	Yes	Yes	Yes
Kovacs et al. (36)	Yes	No	Yes	No	Yes
Lehmann et al. (37)	Yes	No	Yes	Yes	Yes
Melloh et al. (38)	Yes	Yes	Yes	Yes	Yes
Poiraudeau et al. (39)	Yes	Yes	Yes	Yes	Yes
Reeser et al. (40)	Yes	Yes	No	Yes	Yes
Schiottz-Christensen et al. (41)	Yes	No	Yes	Yes	Yes
Shaw et al. (42)- (44)	Yes	No	Yes	Yes	Yes
Sieben et al. (45)	Yes	No	No	Yes	Yes
Sieben et al. (46)	Yes	No	No	Yes	Yes
Suri et al. (47)	Yes	Yes	No	No	Yes
Swinkels-Meewisse et al. (48)	Yes	No	No	Yes	Yes
Thomas et al. (49)	Yes	No	Yes	Yes	No
Valat et al. (50)	Yes	No	Yes	No	Yes

↵* Description of source of patients and inclusion and exclusion criteria.
↵† Participants were selected as consecutive cases.
↵‡ Outcome data were available for at least 80% of participants at one follow-up point.
↵§ At least one prognostic outcome was followed up at three months or later.
↵¶ Raw data, percentages, survival rates or continuous outcome reported.