Table 1 Characteristics of CLBP patients according to presence of depression

Age, Mean ± SD

53.90 ± 14.16

45.91 ± 13.73

55.48 ± 13.73

<0.001

 Female, n (%)

187 (44.00)

33 (47.14)

154 (43.38)

0.562

Employment status, n (%)

0.589

 Not currently employed

164 (38.59)

25 (35.71)

139 (39.15)

 Employed

261 (61.41)

45 (64.29)

216 (60.85)

Annual household income, n (%)

0.079

  < ¥3million

83 (19.53)

22 (31.43)

61 (17.18)

 ¥3million to < ¥5million

100 (23.53)

15 (21.43)

85 (23.94)

 ¥5million to < ¥8million

113 (26.59)

15 (21.43)

98 (27.61)

 ¥8million or more

97 (22.82)

12 (17.14)

85 (23.94)

 Decline to answer

32 (7.53)

6 (8.57)

26 (7.32)

Marital status, n (%)

0.021

 Single/Divorced/Separated/Widowed

138 (32.47)

31 (44.29)

107 (30.14)

 Married/living with partner

287 (67.53)

39 (55.71)

248 (69.86)

Education level, n (%)

0.063

 Less than university education

218 (51.29)

43 (61.43)

175 (49.30)

 University education or higher

207 (48.71)

27 (38.57)

180 (50.70)

Body mass index category, n (%)

0.137

 Underweight

52 (12.24)

9 (12.86)

43 (12.11)

 Normal weight

280 (65.88)

39 (55.71)

241 (67.89)

 Overweight

70 (16.47)

16 (22.86)

54 (15.21)

 Obese

19 (4.47 %)

4 (5.71)

15 (4.23)

 Decline to provide weight

4 (0.94 %)

2 (2.86)

2 (0.56)

Smoking behavior, n (%)

0.088

 Never smoked

182 (42.82)

34 (48.57)

148 (41.69)

 Former smoker

132 (31.06)

14 (20.00)

118 (33.24)

 Current smoker

111 (26.12)

22 (31.43)

89 (25.07)

Alcohol use, n (%)

0.975

 Do not drink

116 (27.29)

19 (27.14)

97 (27.32)

 Drink alcohol

309 (72.71)

51 (72.86)

258 (72.68)

Vigorous exercise at least one day in the past month, n (%)

0.198

 Do not exercise

213 (50.12)

40 (57.14)

173 (48.73)

 Exercise

212 (49.88)

30 (42.86)

182 (51.27)

Charlson comorbidity index, Mean ± SD

0.51 ± 2.23

0.83 ± 3.64

0.44 ± 1.83

0.186

Sleep difficulties, n (%)

82 (19.29)

35 (50.00)

47 (13.24)

<0.001

Severity of LBP, n (%)

<0.001

 Mild

186 (47.45)

19 (29.23)

167 (51.07)

 Moderate

172 (43.88)

34 (52.31)

138 (42.20)

 Severe

34 (8.67)

12 (18.46)

22 (6.73)

 Missing

33

5

28

Severity of pain in the prior week (0–10), Mean ± SD

4.48 ± 2.31

5.80 ± 2.26

4.23 ± 2.23

<0.001

Current severity of pain (0–10), Mean ± SD

4.59 ± 2.28

5.86 ± 2.27

4.34 ± 2.20

<0.001

Frequency of problems with pain, n (%)

0.002

 Daily

188 (44.24)

44 (62.86)

144 (40.56)

 4–6 times a week

63 (14.82)

12 (17.14)

51 (14.37)

 2–3 times a week

82 (19.29)

10 (14.29)

72 (20.28)

 Once a week

39 (9.18)

3 (4.29)

36 (10.14)

 2–3 times a month

35 (8.24)

0 (0.00)

35 (9.86)

 Once a month or less often

18 (4.24)

1 (1.43)

17 (4.79)

Type of diagnosing doctor for LBP, n (%)

0.028

 General internist

18 (4.24)

4 (5.71)

14 (3.94)

 Gynecologist

5 (1.18)

0 (0.00)

5 (1.41)

 Orthopedist

353 (83.06)

54 (77.14)

299 (84.23)

 Rheumatologist

4 (0.94)

3 (4.29)

1 (0.28)

 Pain management specialist

3 (0.71)

1 (1.43)

2 (0.56)

 Other

42 (9.88)

8 (11.43)

34 (9.58)

Type of prescribing doctor, n (%)

0.150

 General internist

28 (16.87)

6 (15.38)

22 (17.32)

 Gynecologist

2 (1.20)

0 (0.00)

2 (1.57)

 Orthopedist

116 (69.88)

24 (61.54)

92 (72.44)

 Rheumatologist

5 (3.01)

3 (7.69)

2 (1.57)

 Pain management specialist

1 (0.60)

0 (0.00)

1 (0.79)

 Other

14 (8.43)

6 (15.38)

8 (6.30)

 Missing

259

31

228

Duration of LBP (months), Mean ± SD

112 ± 120

96 ± 99

115 ± 123

0.227

Current use of a prescription medication for pain, n (%)

0.002

 No

259 (60.94)

31 (44.29)

228 (64.23)

 Yes

166 (39.06)

39 (55.71)

127 (35.77)

Current use of NSAIDs prescription for pain, n (%)

0.049

 No

40 (24.10)

14 (35.90)

26 (20.47)

 Yes

126 (75.90)

25 (64.10)

101 (79.53)

 Missing

259

31

228

Use of an OTC product for pain, n (%)

0.861

 No

306 (72.00)

51 (72.86)

255 (71.83)

 Yes

119 (28.00)

19 (27.14)

100 (28.17)

Use of an herbal product for pain, n (%)

0.441

 No

413 (97.18)

69 (98.57)

344 (96.90)

 Yes

12 (2.82)

1 (1.43)

11 (3.10)