Table 6:

Difference between quartile groups on clinical outcomes

Clinical Outcome	Group Comparisons	Estimate	SE	Wald Z	p	Cohen’s d
Study 1 (N=959)
Pain Intensity	IV v. III IV v. II IV v. I III v. II III v. I II v. I	0.49 0.89 0.82 0.40 0.33 0.07	0.18 0.19 0.18 0.19 0.18 0.19	2.76 4.74 4.64 2.13 1.87 0.39	<0.01 <.001 <.001 0.03 0.06 0.69	0.25 0.45 0.43 0.20 - -
Pain Catastrophizing	IV v. III IV v. II IV v. I III v. II III v. I II v. I	7.50 11.90 19.39 4.40 11.88 7.48	0.95 1.01 0.94 1.02 0.95 1.02	7.93 11.75 20.53 4.33 12.52 7.37	<.001 <.001 <.001 <.001 <.001 <.001	0.73 1.10 1.91 0.39 1.13 0.68
Quality of Life	IV v. III IV v. II IV v. I III v. II III v. I II v. I	−12.06 −15.36 −23.29 −3.29 −11.22 −7.93	1.42 1.46 1.48 1.39 1.41 1.45	−8.50 −10.54 −15.79 −2.36 −7.95 −5.47	<.001 <.001 <.001 0.02 <.001 <.001	0.78 0.99 1.46 0.21 0.71 0.50
Activity Limitations	IV v. III IV v. II IV v. I III v. II III v. I II v. I	10.12 10.65 19.37 0.53 9.26 8.73	2.05 2.14 2.18 2.03 2.07 2.15	4.93 4.98 8.91 0.26 4.48 4.05	<.001 <.001 <.001 0.79 <.001 <.001	0.46 0.47 0.83 - 0.40 0.37
Study 2 (N=207)
Pain Intensity	IV v. III IV v. II IV v. I III v. II III v. I II v. I	0.54 0.02 0.31 0.52 0.85 0.33	0.33 0.38 0.39 0.39 0.40 0.45	1.64 0.06 0.79 1.33 2.12 0.75	0.10 0.95 0.42 0.18 0.03* 0.46	− - - - -
Pain Catastrophizing	IV v. III IV v. II IV v. I III v. II III v. I II v. I	3.91 9.56 13.51 5.65 9.61 3.95	1.70 1.89 2.33 1.91 2.35 2.48	2.30 5.07 5.80 2.97 4.10 1.59	0.02* <0.001 <0.001 <0.01 <0.001 0.11	− 0.98 1.31 0.60 0.95 -
Functional Disability	IV v. III IV v. II IV v. I III v. II III v. I II v. I	2.93 4.64 7.57 1.71 4.64 2.92	1.95 2.43 2.35 2.41 2.33 2.74	1.50 1.91 3.23 0.71 1.99 1.07	0.13 0.05 <0.01 0.48 0.05 0.29	− - 0.66 - - -

False Discovery Rate (FDR) Type-1 error control was used for all pairwise comparisons;

^*revealed non-significant after FDR correction.