Work Interventions Within Interdisciplinary Pain Rehabilitation Programs (IPRP) – Frequency, Patient Characteristics, and Association with Self-Rated Work Ability

Figures & data

Table 1 Overview of Patient Characteristics Variables

Variables	Collected by (Instrument, Question(s) or Other Type of Measurement)	Scale or Categories
Demographics
Sex*	Social security number	Man or Woman
Age*	Social security number	Number of years
Health related variables
Pain duration*		Number of days
Pain average last week*	Numeric pain rating scale (NPRS)	0–10 (high score = more pain)
Anxiety*	Hospital Anxiety and Depression Scale (HADS)	0–21 (high score = more symptoms >8 probable case of anxiety)
Depression*	Hospital Anxiety and Depression Scale (HADS)	0–21 (high score = more symptoms >8 probable case of depression)
General health*	RAND-36	0–100 (high score = better health status)
Vitality*	RAND-36	0–100 (high score = better health status)
Physical role function*	RAND-36	0–100 (high score = better health status)
Education/Work variables
Education*	What is your highest accomplished education? 1: elementary school, 2: upper secondary school, 3: College/University, 4: other	Dichotomized into post upper secondary school or not (College/university = 1) (not/other = 0)
Employed or student*	1: Are you employed or self-employed? 2: Are you unemployed? 3: Are you a student? Questions answered by yes or no	Dichotomized into employed, self-employed or student (1) or unemployed (0)
Sick leave compensation*	Do you have any compensation from the SSIA due to illness?	Yes (1) or no (0)
Work importance*	What importance does work have for you in addition to being important as a source of income?	1–5 (high score = low importance)
Self-rated work ability**	Work Ability Index – single item (Assume your work ability as its best is valued 10 score, what score would you give your current work ability?)	0–10 (high score = high work ability)

Notes: *Collected with SQRP questionnaire 1; **collected with SQRP questionnaire 1 and 2.

Table 2 Patient Characteristics for Patients Who Have Participated in IPRP

		All	Women	Men	p (d) or [OR; CI 95%]	Employed or Student	Unemployed	p (d) or [OR; CI 95%]
Demographics
Sex	Women % (n)	79.2 (3018)	79.2 (3018)		------------	79.7 (2343)	76.6 (367)	0.13
	Men % (n)	20.8 (791)		20.8 (791)		20.3 (596)	23.4 (112)
Age	m ± SD	44.7 ± 10.4	44.5 ± 10.3	45.3 ± 10.7	0.05	44.7 ± 10.1	43.2 ± 11.0	4.82E^−3
	Range	18–65	18–65	19–65		18–65	19–64
Health-related variables
Pain duration	m ± SD	3237 ± 3310	3272 ± 3331	3109 ± 3229	0.24	3081 ± 3242	3625 ± 3441	2.30E^−3
Pain average last week	m ± SD	6.6 ± 1.9	6.7 ± 1.9	6.5 ± 2.0	0.01	6.5 ± 1.9	7.0 ± 1.9	2.65 E^−8 (0.28)
	Range 0–10
Anxiety	m ± SD	9.7 ± 4.6	9.8 ± 4.6	9.4 ± 4.5	0.05	9.6 ± 4.6	10.6 ± 4.6	1.10E^−5 (0.22)
	Range 0–21
Depression	m ± SD	9.3 ± 4.3	9.3 ± 4.3	9.5 ± 4.5	0.18	9.1 ± 4.3	9.9 ± 4.4	6.38E^−4
	Range 0–21
General health	m ± SD	39.7 ± 19.3	39.2 ± 19.3	41.5 ± 18.9	2.46E^−3	40.6 ± 19.2	36.8 ± 19.6	1.64E^−4 (0.19)
	Range	0–100	0–100	0–95		0–100	0–90
Vitality	m ± SD	25.0 ± 18.1	24.0 ± 17.8	28.6 ± 18.8	2.37 E^−9 (−0.25)	25.3 ± 18.1	24.3 ± 18.4	0.27
	Range	0–95	0–90	0–95		0–95	0–87
Physical role function	m ± SD	12.5 ± 25.6	12.0 ± 24.9	14.4 ± 27.9	0.03	13.1 ± 26.2	10.6 ± 23.4	0.04
	Range 0–100
Education/work variables
Education: post upper secondary school	% (n)	36.1 (1177)	39.7 (1032)	22.0 (145)	5.39 E^−18 [0.43;0.35–0.52]	39.5 (1018)	24.2 (94)	3.99 E^−9 [2.0;1.60–2.61]
Employed or student	% (n)	86.0 (2939)	86.5 (2343)	84.2 (596)	0.13	86.0 (2939)	14.0 (479)	-----------
Sick leave compensation	% (n)	61.8 (2184)	63.0 (1751)	57.7 (433)	0.01	61.1 (1671)	56.7 (267)	0.07
Work importance	m ± SD	1.8 ± 0.8	1.8 ± 0.8	1.8 ± 0.8	0.88	1.7 ± 0.8	1.8 ± 0.9	0.03
	Range 1–5
Self-rated work ability	m ± SD	3.4 ± 2.5	3.4 ± 2.6	3.3 ± 2.5	0.55	3.7 ± 2.6	2.5 ± 2.2	1.98 E^−22 (0.46)
	Range 0–10

Notes: Separately presented for sex and employment status at inclusion of IPRP. Bold text denotes differences between groups presented at p < 0.0006.

Abbreviations: CI, confidence interval; d, Cohen´s d; m, mean; n, number; OR, Odds ratio; p, p-value; SD, standard deviation.

Table 3 Differences in Patient Characteristics at Inclusion of IPRP Between Patients Who Had or Had Not Participated in Different Work Interventions During IPRP

	Ergonomic Intervention		RTW Plan		Stakeholder Meeting		Workplace Visit
Intervention yes (n)	2229 = 70.4%		2748 = 84.8%		1230 = 32.3%		136 = 4.2%
Intervention no (n)	939 = 29.6%		494 = 15.2%		2579 = 67.7%		3069 = 95.8%
Missing (n)	641 = 16.8%		567 = 14.9%		0*		604 = 15.9%
Demographics	%yes vs %no or m diff yes-no CI 95%	p [OR; CI 95%] or (d)	%yes vs %no or m diff yes-no CI 95%	p [OR; CI 95%] or (d)	%yes vs %no or m diff yes-no CI 95%	p [OR; CI 95%] or (d)	%yes vs %no or m diff yes-no CI 95%	p [OR; CI 95%] or (d)
Sex (man)	23.4% vs 16.2%	5.00E^−6 [1.58; 1.29–1.93]	21.5% vs 18.4%	0.13	18.9% vs 21.6%	0.06	19.1% vs 21.1%	0.67
Age	0.46	0.26	0.87	0.10	−0.15	0.67	1.01	0.27
	−0.33–1.25		−0.16–1.90		−0.84 – −0.54		−0.78–2.80
Health-related variables
Pain duration	29.7	0.83	−332.0	0.09	−64.4	0.59	−169.8	0.54
	−244.7–304.2		−709.7–45.8		−300.7–172.0		−716.9–377.3
Pain average last week	−0.21	0.01	0.10	0.33	0.10	0.15	0.02	0.90
	−0.38–0.05		−0.10–0.30		−0.04–0.24		−0.30–0.34
Anxiety	0.67	2.88E^−4 (0.15)	0.27	0.25	−0.18	0.26	0.65	0.09
	0.31–1.03		−0.19–0.73		−0.49–0.14		−0.10–1.40
Depression	0.94	6.26 E^−8 (0.22)	0.45	0.04	−0.49	1.13E^−3	0.34	0.38
	0.60–1.28		0.01–0.88		−0.79 – −0.20		−0.43–1.10
General health	2.83	3.01E^−4 (0.15)	1.41	0.17	−0.50	0.46	2.26	0.23
	1.30–4.36		−0.62–3.44		−1.81–0.82		−1.43–5.94
Vitality	−3.51	7.28 E^−7 (0.19)	−1.81	0.04	2.68	1.80E^−5 (−0.15)	0.94	0.57
	−4.89 – −2.12		−3.56–0.07		1.46–3.90		−2.29–4.16
Physical role function	2.94	0.01	0.10	0.94	−2.71	0.002	−2.89	0.16
	0.79–5.10		−2.50–2.70		−4.43 – −1.00		−6.90–1.12
Education/work variables
Education: post upper secondary school	33.6% vs 42.3%	2.10E^−5 [0.69; 0.58–0.82]	35.5% vs 38.4%	0.28	33.8% vs 37.3%	0.05	42.4% vs 35.7%	0.14
Employed or student	86.5% vs 85.3%	0.40	86.5% vs 83.7%	0.16	86.4% vs 85.8%	0.64	92.4% vs 85.8%	0.04
Sick leave compensation	59.8% vs 65.1%	0.01	61.4% vs 63.4%	0.43	70.6% vs 57.4%	1.89 E^−14 [1.78; 1.53–2.07]	60.6% vs 61.4%	0.85
Work importance	0.08	0.01	0.18	8.10E^−5 (0.22)	0.01	0.72	0.01	0.85
	0.02–0.15		0.09–0.27		−0.05–0.07		−0.12–0.14
Self-rated work ability	−0.70	6.71 E^−10 (0.27)	−0.58	1.50E^−5 (0.23)	0.49	4.04 E^−8 (−0.19)	−0.02	0.95
	−0.92 – −0.48		−0.83 – −0.32		0.31–0.66		−0.47–0.44

Notes: Percent of participation vs non-participation and Odds ratio (OR) for dichotomized variables, and medium difference with CI 95% between participation vs non-participation and Cohen’s d (d) for continuous variables. *No missing due to the coding procedure, where the missing and the “not offered intervention” could not be distinguished. Bold text denotes differences between groups presented at p < 0.0006. Continuous variables: age (years), pain duration (days), pain average last week (0–10), anxiety and depression (0–21), general health, vitality, and physical role function (0–100), work importance (1–5), self-rated work ability (0–10).

Abbreviations: CI, confidence interval; d, Cohen’s d; m diff, mean difference; OR, Odds ratio; p, p-value.

Table 4 Association Between Change in Self-Rated Work Ability from Inclusion to End of IPRP and Participation in Work Interventions

Intervention and Interaction Variables	n	B	t	p	95% CI for B		Partial eta^2	R^2
Ergonomic + self-rated work ability initial	1849							0.20
Constant		2.15	21.51	<0.001	1.95	2.34
Self-rated work ability initial		−0.40	−23.78	<0.001	−0.44	−0.37
Ergonomic intervention		0.36	3.73	<0.001	0.17	0.55
Ergonomic + self-rated work ability initial +
Sex + employment + interactions								0.20
Constant		1.70	7.16	<0.001	1.23	2.16
Self-rated work ability initial		−0.42	−24.20	<0.001	−0.45	−0.38	0.20
Ergonomic intervention		0.40	1.46	0.14	−0.14	0.93	0.003
Sex		−0.02	−0.09	0.93	−0.48	0.44	<0.001
Interaction sex × ergonomic intervention		0.08	0.30	0.76	−0.43	0.59	<0.001
Employment		0.56	2.26	0.02	0.08	1.05	0.006
Interaction employment × ergonomic intervention		−0.05	−0.17	0.87	−0.61	0.51	<0.001
RTW plan + self-rated work ability initial	2250							0.20
Constant		1.85	13.13	<0.001	1.57	2.12
Self-rated work ability initial		−0.41	−24.14	<0.001	−0.44	−0.37
RTW plan		0.67	4.83	<0.001	0.40	0.94
RTW plan + self-rated work ability initial +
Sex + employment + interactions								0.21
Constant		0.49	1.36	0.17	−0.21	1.19
Self-rated work ability initial		−0.42	−24.51	<0.001	−0.45	−0.38	0.20
RTW plan		1.74	4.61	<0.001	1.00	2.48	0.006
Sex		0.42	1.10	0.27	−0.32	1.15	0.001
Interaction sex × RTW plan		−0.40	−1.02	0.31	−1.17	0.37	<0.001
Employment		1.54	4.03	<0.001	0.79	2.29	0.009
Interaction employment × RTW plan		−1.17	−2.91	<0.001	−1.96	−0.38	0.004
Stakeholder meeting + self-rated work ability initial	1064							0.20
Constant		2.62	32.62	<0.001	2.46	2.78
Self-rated work ability initial		−0.41	−25.39	<0.001	−0.45	−0.38
Stakeholder meeting		−0.44	4.62	<0.001	−0.61	−0.28
Stakeholder meeting + self-rated work ability initial +
Sex + employment + interactions								0.21
Constant		2.05	13.63	<0.001	1.75	2.34
Self-rated work ability initial		−0.43	−25.91	<0.001	−0.46	−0.39	0.21
Stakeholder meeting		−0.03	−0.11	0.92	−0.48	0.43	0.003
Sex		0.20	1.61	0.11	−0.04	0.45	<0.001
Interaction sex × stakeholder meeting		−0.30	−1.46	0.14	−0.71	0.10	0.001
Employment		0.67	4.32	<0.001	0.36	0.97	0.005
Interaction employment × stakeholder meeting		−0.42	−1.71	0.09	−0.90	0.06	0.001
Workplace visit + self-rated work ability initial	116							0.18
Constant		2.28	32.80	<0.001	2.15	2.42
Self-rated work ability initial		−0.39	−23.78	<0.001	−0.42	−0.35
Workplace visit		0.18	0.89	0.38	−0.21	0.56
Workplace visit + self-rated work ability initial +
Sex + interaction								0.18
Constant		2.27	31.03	<0.001	2.13	2.41
Self-rated work ability initial		−0.39	−23.77	<0.001	−0.42	−0.35	0.18
Workplace visit		0.11	0.51	0.61	−0.32	0.54	0.001
Sex		0.07	0.64	0.52	−0.14	0.27	<0.001
Interaction sex × workplace visit		0.36	0.71	0.48	−0.64	1.36	<0.001

Notes: Results from analysis of each intervention shown separately and adjusted for self-rated work ability initial, sex, and employment. Bold values indicate significant association at p < 0.001. R², proportion of variation explained by the model.

Abbreviations: n, number; B, regression coefficient; t, t-value; p, p-value; CI, confidence interval.