Training GPs to improve their management of work-related problems: results of a cluster randomized controlled trial

Figures & data

Figure 1. Flow chart of cluster RCT.

Table 1. Baseline characteristics of all patients and of patients who completed both questionnaires.

	All patients			Patients who completed both questionnaires
	Intervention	Control	P-value	Intervention	Control	P-value
n	308	332		128	153
Female (%)	57.8	58.1	0.93	60.9	56.9	0.93
Age (mean ± SD)	43.9 ± 10.4	45.1 ± 11.1	0.15	45.4 ± 9.6	45.1 ± 11.1	0.32
Working hours per week (mean ± SD)	32.0 ± 10.5	31.2 ± 10.9	0.37	31.2 ± 11.0	30.6 ± 11.3	0.66
Could health problem be work-related? %
n	307	328		128	151
Yes	34.2	32.0	0.56	30.5	30.5	0.99
GP should know occupation of patients %
n	308	332		128	153
Yes	93.8	92.5	0.77	96.1	91.5	0.5
GP should advise taking sick leave %
n	306	332		128	153
Yes	85.6	83.7	0.77	86.7	81.7	0.52
Education
n	307	331		128	153
Low	12.4	13.3		8.6	10.5
Middle	50.5	58.6	0.05	54.7	65.4	0.07
High	37.1	28.1		36.7	24.2
Sector %
n	301	326		127	150
Blue collar	22.6	23.6		18.1	24.0
White collar	43.5	41.7	0.9	40.9	38.0	0.49
Health; education; other professional^a	33.9	34.7		40.9	38.0
Employment %
n	304	328		128	151
Self-employed	9.5	9.4		5.5	7.3
Permanent	75.1	75.8	0.92	82.8	80.8	0.82
Temporary	15.1	13.9		11.7	11.9
Monthly income %
n	303	328		127	151
< €1000	16.5	20.1		16.5	21.2
€1000–€2000	46.5	43.3		44.9	37.1
€2000–€3000	21.1	19.2	0.73	27.6	23.8	0.32
> €3000	5.9	6.7		5.5	7.3
Not known/no answer	9.9	10.7		5.5	10.6
Experienced health %
n	304	328		129	151
Excellent	3.3	4.6		4.7	4.0
Very good	17.8	14.9		15.5	13.2
Good	59.2	62.5	0.62	61.2	65.6	0.9
Fair	18.4	17.4		17.1	16.6
Poor	1.3	0.6		1.6	0.7
Presence of chronic illness? %
n	303	328		128	151
Yes	39.6	39.9	0.93	37.5	43.7	0.29
Days of sick leave in the last 12 months %
n	299	323		127	151
0–5 days	68.6	70.3		66.9	69.5
6–20 days	16.4	17.3	0.61	13.4	19.2	0.09
> 20 days	15.1	12.4		19.7	11.3
Number of visits to general practitioner in the last six months %
n	289	306		126	147
None	7.3	10.8		5.6	9.5
1 - 2	50.9	54.9	0.08	54.0	52.4	0.47
≥ 3	41.9	34.3		40.5	38.1
Number of visits to occupational physician in the last six months %
n	295	313		127	150
None	80.7	85.0		78.7	84.0
1	8.5	6.7	0.37	10.2	6.0	0.4
≥ 2	10.8	8.3		11.0	10.0

^a e.g. information technology professional, architect, copywriter etc. P-values were calculated using t-tests (for variables Age and Working hours per week) and chi square tests (all other variables).

Table 2. Baseline values and estimated marginal means at follow-up for primary patient-level outcome and primary and secondary GP-level outcomes.

	Intervention group		Control group
	n		n		P-value
Primary patient-level outcome measureWork-related self-efficacy (RTW-SE)
Value at baseline (mean ± SD)	308	4.7 ± 1.4	332	4.7 ± 1.2	0.84
Estimated marginal means at follow-up (95% CI)	128	4.6 (4.2–5.0)	153	4.5 (4.1–4.9)	0.74
Primary GP-level outcome measures
Use of ICPC-code Z05 in EMR per 1000 working-age patients
Value over pre-period (mean ± SD)	15	3.7 ± 4.4	14	4.8 ± 4.0	0.5
Estimated marginal means for post-period (95% CI)	15	11.6 (4.65 - 18.61)	14	6.0 (-1.22–13.23)	0.26
Percentage of patients with information about occupation in EMR
Value over pre-period (mean ± SD)	14	13.9 ± 7.6	14	14.7 ± 7.4	0.8
Estimated marginal means for post-period (95% CI)	14	28.8 (25.83 - 31.74)	14	28.6 (25.64–31.55)	0.93
Secondary GP-level outcome measure
GWAS (aggregated mean score)
Value at baseline (mean ± SD)	16	2.2 ± 0.6	14	2.3 ± 0.6	0.77
Estimated marginal means at follow-up (95% CI)	14	2.5 (2.1–2.79)	13	2.1 (1.82 - 2.44)	0.1

SD, standard deviation; CI, confidence interval; EMR, electronic medical record; GWAS, GP work-awareness scale. P-values were calculated using t-test (for baseline values) and ANCOVA for (follow up and post-period values).