Association between self-perceived pain sensitivity and pain intensity after cardiac surgery

Figures & data

Figure 1 Participant flow through the study.

Table 1 Participant characteristics stratified by sex (N=416)

Characteristics		Men (n=322)	Women (n=94)	p valuea
Age at inclusion	Years, mean±SD	65±10	70±12	<0.001
Education	Less than high school/secondary, n (%)	46 (16)	24 (27)	0.015
	High school/secondary or higher, n (%)	245 (84)	64 (73)
Marital status	Married/cohabitant/partner, n (%)	241 (80)	41 (46)	<0.001
	Divorced/widowed/single, n (%)	59 (20)	49 (54)
Type of surgery	Isolated CABG, n (%)	165 (51)	26 (28)	< 0.001
	Isolated heart valve, n (%)	116 (36)	57 (61)
	CABG and valve, n (%)	41 (13)	11 (11)
Comorbiditiesb	Count, median (range)	1 (0–6)	2 (0–6)	0.010

Notes:

a p values obtained from Student’s t-test or Mann–Whitney U-test (continuous variables) and Pearson chi-square tests (categorical variables).

b Self-administered Comorbidity Questionnaire.

Abbreviations: CABG, coronary artery bypass graft; SD, standard deviation.

Table 2 Pain sensitivity ratings at inclusion and worst pain intensity during 1-year follow-up stratified by sex

Characteristics		Men (n=322)	Women (n=94)	p valuea
PSQb at inclusion	Total, mean±SD	3.2±1.3	3.4±1.8	0.178
	Moderate, mean±SD	4.4±1.6	4.5±1.9	0.739
	Minor, mean±SD	2.0±1.1	2.4±1.7	0.012
Worst pain intensityc	Pre-surgery, mean±SD	3.0±2.3	3.3±2.4	0.322
	Post-surgery
	Day 1, mean±SD	6.0±2.2	6.0±2.4	0.942
	Day 2, mean±SD	5.3±2.2	5.7±2.0	0.195
	Day 3, mean±SD	4.6±2.2	4.9±2.2	0.555
	Day 4, mean±SD	4.4±2.4	4.9±2.7	0.451
	2 weeks, mean±SD	3.5±2.3	3.5±3.5	0.921
	1 month, mean±SD	2.5±2.1	2.8±2.3	0.431
	3 months, mean±SD	1.4±1.9	1.8±2.7	0.013
	6 months, mean±SD	1.2±1.7	2.0±2.4	0.031
	12 months, mean±SD	1.0±1.9	1.7±2.5	0.034

Notes:

a p values obtained from Student’s t-test (continuous variables).

b PSQ score ranges from 0 (not painful) to 10 (worst pain).

c Brief Pain Inventory Short Form score ranges from 0 (no pain) to 10 (worst pain imaginable).

Abbreviations: PSQ, Pain Sensitivity Questionnaire; SD, standard deviation.

Figure 2 Association between pain sensitivity and worst pain intensity across time.

Note: This figure is based on the mixed model shown in Table 3.
Abbreviation: PSQ, Pain Sensitivity Questionnaire.

Table 3 Linear mixed model for worst pain intensity during 1-year follow-up after cardiac surgery

Variables	Coefficient	95% CI	p value
Timea	−0.13	−0.24, 0.02	0.017
Time squared	−0.04	−0.05, −0.03	0.646
PSQ-totalb	0.16	0.06, 0.26	0.001
Sexc	0.01	−0.43, 0.45	0.981
Aged	−0.03	−0.04, −0.02	<0.001
Educational statuse	0.22	−0.14, 0.6	0.233
Marital statusf	−0.29	0.11, 1.53	0.162
Sex × marital status	0.82	0.11, 1.53	0.023
Comorbiditiesf	0.31	0.21, 0.41	<0.001

Notes:

a Time after surgery (time 0=baseline) in months.

b PSQ-total score ranges from 0 (not painful) to 10 (worst pain).

c Men=0, women=1.

d Age at surgery in years.

e Less than high school/secondary=0, high school/secondary or higher=1.

f Married/cohabitant/partner=0, divorced/widowed/single=1.

g Number of comorbidities from the Self-administered Comorbidity Questionnaire.

Abbreviations: CI, confidence interval; PSQ, Pain Sensitivity Questionnaire.