Table 2 Comparison of baseline characteristics between participants with LBP who did (FU) and did not (NFU) follow-up at 3, 6, 9 and 12 months

Demographic, health & function

Age (years)^‡

28 (22–34)

24 (20–32)

0.074

27 (22–34)

26.5 (20.5–33.5)

0.362

27.5 (22.5–34)

25 (21–34)

0.264

27 (22.5–35)

25 (20–31)

0.090

Sex (% female)

48.0

62.9

0.130

49.4

56.8

0.423

50.0

55.1

0.570

51.1

53.7

0.784

Height (m)^†*

1.73 (0.09)

1.70 (0.09)

0.078

1.73 (0.09)

1.71 (0.09)

0.173

1.73 (0.09)

1.72 (0.09)

0.615

1.73 (0.09)

1.71 (0.09)

0.507

Weight (kg)^‡*

73 (63–82)

72 (56–85)

0.746

73 (62–82)

73.5 (60.5–84.5)

0.815

72.5 (62.5–82.5)

74 (61–84)

0.744

71.5 (60.5–81.5)

75 (62–85)

0.680

BMI (kg/m²)^‡

24.0 (21.4–26.3)

25.2 (21.0–27.7)

0.409

24.0 (21.4–26.3)

24.1 (21.7–27.5)

0.449

24.0 (21.8–26.3)

23.9 (21.1–27.2)

0.961

23.9 (21.4–26.1)

25.9 (21.2–27.4)

0.313

Comorbidity (yes, %)

41.8

54.3

0.204

42.7

50.0

0.426

40.5

53.1

0.159

0.5

41.5

0.572

Previous LBP (yes, %)

92.9

88.6

0.429

92.1

90.9

0.809

91.7

91.8

0.973

92.4

90.2

0.678

Healthcare utilization (yes, %)

18.4

23.5

0.514

20.2

18.6

0.826

21.4

16.7

0.508

19.6

20.0

0.954

Medication utilization (yes, %)

18.8

32.1

0.152

21.1

25.0

0.650

19.7

26.8

0.390

16.7

34.3

0.040

Function (LBOS)^†

48.4 (11.2)

42.7 (10.8)

0.012

48.3 (10.7)

44.1 (12.2)

0.048

48.2 (10.5)

44.6 (12.4)

0.077

48.1 (11.0)

44.1 (11.7)

0.060

Outcome

Pain (NRS)^‡

5 (3–6)

6 (5–7)

0.019

5 (3–6)

6 (4–7)

0.078

5 (3–7)

5 (4–7)

0.506

5 (3–6.5)

6 (4–7)

0.147

Disability (RMDQ)^‡

6 (3–9)

7 (4–11)

0.140

6 (3–9)

6.5 (4–10.5)

0.293

6 (4–9)

6 (4–10)

0.613

6 (4–9)

7 (4–10)

0.257

Psychological

Depressive symptoms (CES-D)^‡

11 (7–17)

16 (10–25)

0.003

10 (7–17)

16 (10–22)

0.008

10 (7–18)

15 (10–22)

0.004

10 (7–18)

15 (11–23)

0.017

Pain catastrophizing (PCS)^‡

10 (6–16)

19 (7–26)

0.057

10 (6–16)

13 (7–26)

0.125

10 (6–16)

14 (7–26)

0.106

10 (6–16)

17 (9–26)

0.019

Fear avoid.-work (FABQ-W)^‡

11 (2–17)

15 (6–22)

0.136

12 (2–17)

12 (3–24)

0.223

12 (3–17)

13 (4–23)

0.144

12 (4–17)

10 (0–23)

0.960

Fear avoid.-activity (FABQ-PA)^†

14.7 (5.5)

14.9 (5.4)

0.835

14.7 (5.3)

14.8 (5.8)

0.944

14.6 (5.6)

15.0 (5.4)

0.686

14.8 (5.4)

14.7 (5.8)

0.926

Pain self-efficacy (PSEQ)^‡

48 (40–53)

41 (32–48)

0.008

48 (40–52)

44 (32–48)

0.021

48 (40–53)

44 (32–48)

0.009

47 (40–53)

45 (32–48)

0.047

Social

Marital status (not married/cohabitating, %)

65.3

58.8

0.498

64.0

62.8

0.888

64.3

62.5

0.837

63.0

65.0

0.830

Edu. level (secondary school/below, %)

24.5

26.5

0.818

24.7

25.6

0.915

23.8

27.1

0.676

25.0

25.0

1.000

Empl. status (unemployed, %)

25.5

14.7

0.195

25.8

16.3

0.219

25.0

18.8

0.410

20.7

27.5

0.388

Job satisfaction (NRS)^†

4.3 (1.2)

3.8 (1.1)

0.070

4.3 (1.2)

3.9 (1.2)

0.092

4.3 (1.2)

3.8 (1.1)

0.025

4.3 (1.2)

3.8 (1.1)

0.044

Job skill discretion (JCQ)^‡

38 (32–42)

34 (28–40)

0.249

38 (32–42)

34 (30–40)

0.213

38 (32–42)

34 (30–39)

0.148

38 (32–41)

36 (32–40)

0.470

Job decision-making authority (JCQ)^‡

40 (32–44)

36 (28–42)

0.081

40 (32–44)

36 (28–44)

0.136

40 (36–44)

36 (28–40)

0.026

40 (32–44)

36 (28–44)

0.254

Job demands (JCQ)^‡

32 (27–36)

33 (31–38)

0.096

32 (27–36)

33 (30–38)

0.068

32 (27–36)

33 (29–38)

0.214

32 (29–36)

33 (26–38)

0.922

Job decision latitude (JCQ)^‡

76 (66–86)

70 (56–80)

0.152

76 (67–86)

70 (62–82)

0.172

77 (68–86)

70 (60–80)

0.058

76 (66–86)

74 (62–82)

0.353

Co-worker support (JCQ)^‡

12 (12–14)

12 (11–12)

 < 0.001

12 (12–14)

12 (11–12)

0.002

13 (12–14)

12 (11–12)

 < 0.001

12 (12–14)

12 (12–13)

0.190

Supervisor support (JCQ)^‡

12 (12–15)

12 (11–14)

0.341

12 (12–15)

12 (11–14)

0.411

12 (12–16)

12 (11–13)

0.122

12 (11–16)

12 (11–13)

0.530

Job insecurity (JCQ)^‡∆

5 (4–7)

6 (5–8)

0.156

5 (4–7)

6 (5–7)

0.088

5 (4–7)

6 (5–8)

0.046

5 (4–7)

5 (5–7)

0.308

Sick days over last 12 months^‡*

2 (0–4)

2 (0–5)

0.618

2 (0–4)

2 (0–5)

0.711

2 (0–4)

2 (0–5)

0.803

2 (0–4)

2 (0–5)

0.975

Sickness benefits for LBP (yes, %)

1.3

3.6

0.439

1.4

2.8

0.621

1.5

2.4

0.732

0.0

5.7

0.041

Impending compensation (yes, %)

6.3

17.9

0.072

7.0

13.9

0.250

7.6

12.2

0.425

4.2

20.0

0.008

Behavioural

Sleep quality (PSQI)^†

9.0 (3.3)

10.0 (3.2)

0.215

9.0 (3.4)

9.7 (3.1)

0.337

9.0 (3.5)

9.6 (3.0)

0.334

9.2 (3.5)

9.1 (2.9)

0.828

Alcohol use/related problems (AUDIT)^‡

3 (2–6)

3 (1–7)

0.996

3 (2–6)

3 (1–7)

0.778

3 (1–6)

3 (2–8)

0.617

3 (2–6)

3 (1–8)

0.742

Previous/current smoker (yes, %)

35.7

38.2

0.792

36.0

37.2

0.888

34.5

39.6

0.561

35.9

37.5

0.858

Current smoker (yes, %)

6.1

11.8

0.284

6.7

9.3

0.602

6.0

10.4

0.351

5.4

12.5

0.159

Vig. phys. activity days/week (IPAQ)^‡*

2 (0–3)

1 (0–3)

0.783

2 (0–3)

2 (0–4)

0.312

2 (0–3)

2 (0–3)

0.606

2 (0–3)

1 (0–2)

0.233

Vig. phys. activity time/day (min, IPAQ)^‡*

20 (0–60)

20 (0–60)

0.728

18 (0–60)

30 (0–60)

0.263

20 (0–60)

25 (0–60)

0.700

28 (0–60)

0 (0–60)

0.575

Mod. phys. activity days/week (IPAQ)^‡*

2 (1–4)

2 (0–4)

0.979

2 (1–4)

2 (0–4)

0.743

2 (1–4)

2 (0–4)

0.874

2 (1–4)

2 (0–4)

0.228

Mod. phys. activity time/day (min, IPAQ)^‡*

30 (0–60)

30 (0–30)

0.082

30 (0–60)

23 (0–30)

0.070

30 (0–60)

30 (0–35)

0.113

30 (0–60)

30 (0–45)

0.233

Days/week walking for ≥ 10 min (IPAQ)^‡*

6 (4–7)

6 (4–7)

0.806

6 (4–7)

6 (3–7)

0.594

6 (4–7)

6 (4–7)

0.747

6 (4–7)

6 (4–7)

0.729

Walking time/day (min, IPAQ)^‡*

30 (18–60)

30 (20–90)

0.158

30 (20–45)

35 (20–75)

0.118

25 (15–40)

45 (20–75)

0.023

25 (20–45)

48 (20–60)

0.076

Sitting time/day (min, IPAQ)^†*

430.6 (174.8)

385.0 (211.3)

0.298

429.4 (173.6)

394.3 (209.9)

0.401

437.3 (176.1)

381.3 (198.6)

0.166

428.7 (173.6)

393.5 (212.5)

0.410