Central Sensitivity Is Associated with Poor Recovery of Pain: Prediction, Cluster, and Decision Tree Analyses

Table 1

Characteristics of each variable in each cluster.

Variable	Total	Cluster 1 (n = 10)	Cluster 2 (n = 21)	Cluster 3 (n = 12)	value	Trend test^¶
Age (years)	72.2 ± 12.9	75.0 ± 8.8	72.6 ± 9.3	69.2 ± 19.2		—
Gender (female)	10 (33)	2 (8)	8 (13)	0 (12)		—
Pain duration (month)	11.8 ± 30.2	20.2 ± 34.7	8.2 ± 25.1	11.2 ± 32.8		—
Disease classification	MSK-NO : 22	MSK-NO : 7	MSK-NO : 10	MSK-NO : 5		—
	MSK-O : 13	MSK-O : 2	MSK-O : 5	MSK-O : 6
	CND-B : 5	CND-B : 0	CND-B : 5	CND-B : 0
	CND-S : 3	CND-S : 1	CND-S : 1	CND-S : 1
SFMPQ-2 BL	40.0 ± 33.2	32.7 ± 27.1	21.4 ± 14.2	78.8 ± 28.9
SFMPQ-2 FU	28.4 ± 27.1	56.7 ± 25.9	14.5 ± 11.5	29.3 ± 28.7
∆SFMPQ-2 observed	−11.6 ± 30.1	24.0 ± 11.3	−6.9 ± 9.1	−49.5 ± 21.7
∆SFMPQ-2 predicted	−24.3 ± 17.4	−20.5 ± 14.2	−14.5 ± 7.4	−44.6 ± 15.1
∆SFMPQ-2 observed-predicted	12.7 ± 23.3	44.4 ± 15.2	7.7 ± 7.7	−4.9 ± 21.2
CSI-9 BL	13.8 ± 7.4	17.3 ± 9.0	10.2 ± 5.8	17.3 ± 5.5
CSI-9 FU	11.1 ± 6.9	15.7 ± 8.3	9.3 ± 5.5	10.4 ± 6.1
∆CSI-9	−2.7 ± 6.0	−1.6 ± 6.5	−0.9 ± 4.5	−6.8 ± 6.0
HADS-A BL	5.8 ± 4.2	6.1 ± 2.7	4.9 ± 4.3	7.1 ± 4.7
HADS-A FU	5.6 ± 4.1	7.6 ± 3.5	4.5 ± 3.8	5.8 ± 4.2
∆HADS-A	−0.2 ± 3.3	1.5 ± 4.0	−0.4 ± 2.6	−1.3 ± 3.2
HADS-D BL	6.1 ± 3.2	6.3 ± 3.7	6.0 ± 2.9	6.0 ± 3.1
HADS-D FU	5.9 ± 3.5	6.7 ± 3.6	5.3 ± 3.4	6.2 ± 3.4
∆HADS-D	−0.2 ± 3.1	0.4 ± 4.1	−0.6 ± 2.0	0.2 ± 3.5
PCS-4 BL	9.4 ± 4.3	9.3 ± 4.2	8.2 ± 4.0	11.4 ± 4.1
PCS-4 FU	7.1 ± 4.4	8.6 ± 3.4	5.9 ± 4.3	8.0 ± 4.6
∆PCS-4	−2.3 ± 3.8	−0.7 ± 2.8	−2.3 ± 2.9	−3.4 ± 5.3

Values are numbers for categorical variables and mean and SD for continuous variables unless otherwise indicated. Abbreviations: SFMPQ-2, Short-Form McGill Pain Questionnaire-2; CSI-9, Central Sensitisation Inventory-9; HADS-A, Hospital Anxiety and Depression Scale-Anxiety; HADS-D, Hospital Anxiety and Depression Scale-Depression; PCS-4, Pain Catastrophising Scale-4; BL, baseline; FU, follow-up; ∆, follow-up score minus the initial score; MSK-NO, musculoskeletal-nonoperative; MSK-O, musculoskeletal-operative; CND-B, central nerve disease-brain; CND-S, central nerve disease-spinal cord. : assessed by one-way analysis of variance. #: assessed by the Kruskal–Wallis test; ^§: assessed by Fisher’s exact test. Assessed by the Jonckheere–Terpstra trend test.