The clinical course of low back pain: a meta-analysis comparing outcomes in randomised clinical trials (RCTs) and observational studies

Table 1 Characteristics of included observational cohort studies (n 19)

Author and country	Population and setting	Age, mean (y)	Female%	Type of back pain	Sample size
Bakker et al., Netherlands [17]	GP consulters	41	48	Acute	97
Bekkering et al., Netherlands [18]	Physiotherapy consulters	45	52	Mixed	500
Carey et al., USA [19]	GP and chiropractic consulters	42	52	Acute	1628
Chenot et al., Germany [20]	GP consulters	44		Mixed	1342
Coste et al., France [21]	GP consulters	46	40	Acute	103
Demmelmeir et al., Sweden [22]	General population	42	55	Mixed	379
Dunn et al., UK [23]	GP consulters			Mixed	206
Grotle et al., Norway [24]	Primary care	38	55	Acute	123
Hass et al., Netherlands [25]	Community chiropractic clinics	43	53	Mixed	2780
Kovacs et al., Spain [26]	GP consulters	46	52	Mixed	648
McGuirk et al., Australia [27]	GP consulters	53	57	Acute	83
Miller et al., UK [28]	GP consulters	39	60	Mixed	211
Nyiendo et al., USA [29]	Medical and chiropractic clinics			Chronic	835
Perreault et al., Canada [30]	Physiotherapy departments	51		Mixed	78
Sefarlis et al., Sweden [31]	GP consulters	39		Acute	60
Sharma et al., USA [32]	Medical and chiropractic clinics consulters	40	50	Mixed	2872
Tamcan et al., Switzerland [33]	General population	42	50	Chronic	340
van Hoogan et al., Netherlands [34]	GP consulters	44	55	Mixed	443
van Tulder et al., Netherlands [35]	GP consulters	41	49	Mixed	368

ISSN: 1471-2474