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Table 2 Associations between the total MDI scale and outcomes and between five candidate items and outcomes

From: Brief screening questions for depression in chiropractic patients with low back pain: identification of potentially useful questions and test of their predictive capacity

  β coefficients (95% CI)
  LBP 3-months LBP 12-months RMDQ 3-months RMDQ 12-months
Total MDI scale
MDI categorised Adj. R2 = 0.03 Adj. R2 = 0.01 Adj. R2 = 0.03 Adj. R2 = 0.02
No depression (reference)     
Mild depression 1.59 (.91; 2.27) .96 (.17; 1.74) 13.14 (5.59;20.68) 6.94 (-.36;14.24)
Moderate depression .89 (.01; 1.78) 1.08 (.08; 2.08) 18.19 (8.64;27.74) 13.26 (4.13;22–38)
Severe depression .78 (-.45; 2.02) 1.24 (-.21; 2.69) 18.45 (4.67; 32.23) 15.11 (1.90;28.32)
Single candidate items
Item 1: Low in spirits or sad Adj. R2 = 0.03 Adj. R2 = 0.04 Adj. R2 = 0.06 Adj. R2 = 0.03
At no time (reference)     
Some of the time 0.53 (0.24; 0.82) 0.52 (0.19; 0.84) 7.15 (3.99; 10.31) 4.88 (1.89; 7.86)
Slightly less than half the time 0.26 (-0.55; 1.08) 0.44 (-0.44; 1.33) 7.41 (-1.48; 16.31) 5.42 (-2.86; 13.71)
Slightly more than half the time 0.80 (0.08; 1.51) 0.32 (-0.52; 1.15) 16.05 (8.35; 23.75) 6.45 (-1.19; 14.09)
Most or all of the time 1.61 (0.71; 2.41) 2.32 (1.39; 3.24) 25.13 (15.81; 34.45) 19.45 (10.98; 27.93)
Item 2: Lost interest Adj. R2 = 0.02 Adj. R2 = 0.03 Adj. R2 = 0.05 Adj. R2 = 0.02
At no time (reference)     
Some of the time 0.16 (-0.14; 0.47) 0.55 (0.21; 0.90) 5.25 (1.90; 8.60) 4.76 (1.63; 7.89)
Slightly less than half the time 0.98 (0.40; 1.56) 1.00 (0.36; 1.65) 16.58 (10.23; 22.93) 6.15 (0.25; 12.06)
Slightly more than half the time 0.34 (-0.23; 0.91) 0.67 (0.01; 1.33) 9.18 (3.00; 15.36) 8.81 (2.79; 14.84)
Most or all of the time 0.86 (0.17; 1.55) 0.76 (-0.01; 1.54) 13.85 (6.30; 21.40) 7.60 (0.51; 14.70)
Item 3: Lacking energy Adj. R2 = 0.04 Adj. R2 = 0.05 Adj. R2 = 0.09 Adj. R2 = 0.05
At no time (reference)     
Some of the time 0.15 (-0.20; 0.49) 0.46 (0.07; 0.84) 3.92 (0.18; 7.65) 1.72 (-1.80; 5.23
Slightly less than half the time 0.67 (0.15; 1.19) 1.07 (0.49; 1.65) 12.26 (6.65; 17.88) 7.73 (2.46; 13.00)
Slightly more than half the time 0.76 (0.24; 1.28) 0.78 (0.17; 1.38) 14.34 (8.75; 19.93) 10.91 (5.37; 16.46)
Most or all of the time 1.33 (0.83; 1.82) 1.50 (0.93; 2.06) 20.71 (15.37; 26.05) 13.79 (8.64; 18.93)
Item 4: Felt less self-confident Adj. R2 = 0.01 Adj. R2 = 0.02 Adj. R2 = 0.04 Adj. R2 = 0.02
At no time (reference)     
Some of the time 0.41 (0.07; 0.75) 0.38 (0.00; 0.76) 4.64 (0.92; 8.36) 4.02 (0.54; 7.50)
Slightly less than half the time 0.54 (-0.21; 1.29) 0.85 (-0.10; 1.79) 9.99 (1.88; 18.11) 9.10 (0.66; 17.54)
Slightly more than half the time 0.70 (-0.06; 1.47) 0.54 (-0.35; 1.42) 15.67 (7.41; 23.93) 7.72 (-0.35; 15.78)
Most or all of the time 1.12 (0.23; 2.02) 1.88 (0.88; 2.88) 16.83 (6.98; 26.69) 16.05 (6.91; 25.18)
Item 8: Restless or slowed down Adj. R2 = 0.02 Adj. R2 = 0.005 Adj. R2 = 0.04 Adj. R2 = 0.01
At no time (reference)   *   
Some of the time -0.03 (-0.35; 0.29) 0.27 (-0.10; 0.63) 3.76 (0.23; 7.28) 3.26 (-0.07; 6.60)
Slightly less than half the time 0.13 (-0.42; 0.69) 0.35 (-0.26; 0.95) 6.41 (0.29; 12.53) 5.42 (-0.09; 10.94)
Slightly more than half the time 0.09 (-0.45; 0.62) 0.40 (-0.21; 1.02) 5.98 (0.10; 11.86) 4.94 (-0.73; 10.60)
Most or all of the time 1.25 (0.66; 1.84) 0.86 (0.18; 1.54) 19.13 (12.67; 25.60) 8.27 (2.02; 14.53)
  1. *All associations between items and outcomes and total MDI and outcomes were statistically significant (p < .05) except for the association between item 8 and LBP at 12-months. Confidence intervals that span across zero indicate that this particular category was not significantly different from the reference.