Table 3

Univariable and multivariable logistic regression

VariableOR95% CIP valueaOR*95% CIP value
ICMJE journal
 Yes1.080.55 to 2.160.821
 No†

Risk of bias
 Low risk2.360.67 to 11.010.213
 Some concerns1.140.56 to 2.370.716
 High risk†

Impact factor
 Upper tertile4.992.14 to 12.32<0.0015.722.23 to 15.85<0.001
 Middle tertile3.321.52 to 7.480.0033.521.51 to 8.570.004
 Lower tertile†

Spinal region
 Cervical2.800.91 to 9.270.0803.040.88 to 11.300.085
 Thoracic0.960.35 to 2.660.9391.090.34 to 3.450.887
 Lumbopelvic†
 Mixed/unclear2.831.15 to 7.110.0253.181.16 to 9.050.027

Type of practitioner
 Chiropractor6.211.71 to 24.850.0074.581.14 to 20.240.036
 Osteopath†
 Physiotherapist1.880.60 to 6.190.2821.350.37 to 5.180.648
 Medical practitioner1.200.22 to 6.530.8310.810.12 to 5.470.829
 Mixed/other/unclear2.720.78 to 10.170.1212.260.57 to 9.640.253

Sample size spinal manipulation group‡
 Upper tertile3.641.57 to 8.870.003-
 Middle tertile1.270.58 to 2.790.544-
 Lower tertile†

*The final model was adjusted for impact factor, spinal region of manipulation, and type of practitioner, while ICMJE journal status, risk of bias and number of participants receiving spinal manipulation were omitted via backward elimination method.

†Reference group.

‡One study with unclear sample size excluded.

aOR, adjusted OR; ICMJE, International Committee of Medical Journal Editors.