Table 3.
Secondary Outcomes Among Participants With Chronic Low Back Paina
| Overall Effect | Intervention Group, Mean (95% CI) | Control Group, Mean (95% CI) | Between-Group Difference, Mean (95% CI)b | P Value | Risk Difference (95% CI) | NNT |
|---|---|---|---|---|---|---|
| Functioning Scorec,d | ||||||
| Facet joint trial, No. of participants | 125 | 126 | ||||
| Overall | 0.04 (−3.02 to 3.10) | .98 | ||||
| 3 mo | 26.03 (23.01 to 29.06) | 28.67 (26.06 to 31.84) | −2.45 (−5.93 to 1.03) | .17 | ||
| 6 mo | 25.38 (22.45 to 28.30) | 27.15 (24.07 to 30.23) | −0.60 (−4.13 to 2.92) | .74 | ||
| 9 mo | 25.74 (22.74 to 28.73) | 24.52 (21.49 to 27.54) | 2.26 (−1.29 to 5.82) | .21 | ||
| 12 mo | 24.59 (21.39 to 27.79) | 25.04 (21.77 to 28.31) | 1.48 (−2.09 to 5.06) | .42 | ||
| Sacroiliac joint trial, No. of participants | 116 | 112 | ||||
| Overall | 0.42 (−2.99 to 3.82) | .81 | ||||
| 3 mo | 27.72 (24.50 to 30.95) | 29.09 (25.47 to 2.71) | −4.20 (−8.39 to −0.00) | .05 | ||
| 6 mo | 25.99 (22.91 to 29.05) | 24.99 (21.45 to 28.52) | 0.07 (−4.16 to 4.30) | .97 | ||
| 9 mo | 28.40 (25.05 to 31.75) | 23.45 (20.00 to 6.91) | 4.45 (0.14 to 8.77) | .04 | ||
| 12 mo | 27.29 (23.89 to 30.69) | 24.49 (20.74 to 28.23) | 2.11 (−2.25 to 6.47) | .34 | ||
| Combination trial, No. of participants | 103 | 99 | ||||
| Overall | 1.90 (−2.96 to 6.76) | .44 | ||||
| 3 mo | 28.00 (24.65 to 31.35) | 33.63 (29.88 to 37.37) | −4.66 (−10.21 to 0.89) | .10 | ||
| 6 mo | 30.24 (26.14 to 34.34) | 28.61 (24.80 to 32.43) | 4.44 (−1.18 to 0.06) | .12 | ||
| 9 mo | 30.73 (26.83 to 34.63) | 28.70 (24.48 to 32.91) | 3.55 (−2.17 to 9.26) | .22 | ||
| 12 mo | 31.20 (27.20 to 35.20) | 24.67 (20.88 to 28.45) | 6.44 (0.61 to 12.26) | .03 | ||
| Global Perceived Recoverye | ||||||
| No. With Treatment Success/Total No. (%) | No. With Treatment Success/Total No. (%) | Relative Risk (95% CI)f | P Value | Risk Difference (95% CI) | NNT | |
| Facet joint trial, No. of participants | 125 | 126 | ||||
| 3 wk | 32/108 (29.63) | 5/101 (4.95) | 5.41 (2.29 to 10.34) | <.001 | 24.68 (15.08 to 34.27) | 4 |
| 6 wk | 35/119 (29.41) | 11/118 (9.32) | 2.71 (1.37 to 4.68) | .005 | 20.09 (10.37 to 29.81) | 5 |
| 3 mo | 43/119 (36.13) | 27/114 (23.68) | 1.35 (0.81 to 2.05) | .24 | 12.45 (0.81 to 24.09) | 8 |
| 6 mo | 46/113 (40.70) | 39/108 (36.11) | 1.04 (0.64 to 1.12) | .85 | 4.59 (−8.21 to 17.41) | NA |
| 9 mo | 41/106 (38.67) | 42/105 (40.00) | 0.81 (0.48 to 0.57) | .35 | −1.33 (−14.50 to 11.86) | NA |
| 12 mo | 44/103 (42.71) | 40/102 (39.22) | 0.90 (0.55 to 1.33) | .65 | 3.49 (−9.95 to 16.96) | NA |
| Sacroiliac joint trial, No. of participants | 116 | 112 | ||||
| 3 wk | 28/94 (29.78) | 9/88 (10.23) | 2.83 (1.39 to 4.89) | .01 | 19.55 (8.35 to 30.77) | 5 |
| 6 wk | 43/110 (39.09) | 10/95 (10.53) | 3.71 (2.00 to 5.74) | <.001 | 28.56 (17.55 to 39.58) | 4 |
| 3 mo | 43/110 (39.10) | 19/88 (21.59) | 1.87 (1.13 to 2.71) | .02 | 17.51 (4.97 to 30.03) | 6 |
| 6 mo | 46/103 (44.66) | 29/88 (32.95) | 1.26 (0.83 to 1.84) | .21 | 11.71 (−2.03 to 25.44) | NA |
| 9 mo | 36/101 (35.64) | 25/78 (32.05) | 1.13 (0.67 to 1.70) | .62 | 3.59 (−10.35 to 17.54) | NA |
| 12 mo | 49/102 (48.03) | 24/76 (31.78) | 1.46 (0.92 to 2.02) | .10 | 16.25 (2.20 to 30.72) | NA |
| Combination trial, No. of participants | 103 | 99 | ||||
| 3 wk | 17/77 (22.07) | 4/56 (7.14) | 2.23 (0.73 to 5.52) | .15 | 14.93 (3.48 to 25.40) | 6 |
| 6 wk | 25/90 (27.77) | 7/82 (8.54) | 2.41 (0.99 to 4.90) | .05 | 19.23 (8.19 to 30.30) | 5 |
| 3 mo | 30/88 (34.09) | 13/80 (16.25) | 1.99 (0.99 to 3.37) | .06 | 17.84 (5.06 to 30.63) | 5 |
| 6 mo | 30/85 (35.29) | 28/75 (37.33) | 0.76 (0.39 to 1.30) | .36 | −2.04 (−16.97 to 12.90) | NA |
| 9 mo | 29/82 (35.36) | 21/68 (30.88) | 1.11 (0.57 to 1.82) | .73 | 4.48 (−10.61 to 19.57) | NA |
| 12 mo | 26/75 (34.66) | 22/61 (36.06) | 0.91 (0.46 to 1.52) | .76 | −1.40 (−17.65 to 14.76) | NA |
aThe other secondary outcomes are presented in eTable 2 in Supplement 2.
bValues presented (for mean differences) are model estimates of linear mixed-effects models with a random intercept, and adjusted for outcome at baseline and age, sex, body mass index, education, smoking, marital status, back pain complaint history, and participant expectations. Regression coefficients can be interpreted as mean differences between interventions at a certain follow-up point compared with baseline.
cMeasured by Oswestry Disability Index (score range, 0-100); a higher score indicates worse functioning.
dThe overall effect measures provide information over the total follow-up time of 12 mo, instead of the time × treatment effects.
eMeasured by the Global Perceived Effect scale (range, 1-7); a score of 1 to 2 indicates success.
fRelative risk was estimated based on the method of Zhang et al.