Prevalence of- and risk factors for work disability in Dutch patients with inflammatory bowel disease

Table 1 Definition of used parelsnoer information model items

Diagnosis of IBD
Crohn’s disease Ulcerative colitis IBD-unclassified IBD-Indeterminate	Diagnosis of IBD was defined by clinical symptoms of the disease and confirmed by endoscopy, radiology or histology. If differentiation between CD and UC was not possible, patient were classified as Inflammatory Bowel Disease Unclassified (IBD-U). In the case that a pathologist was not able to differentiate between CD or UC following colectomy, the patient was classified as Inflammatory Bowel Disease Indeterminate (IBD-I).
Family history of IBD
	Family history of IBD was registered up to 3rd degree relatives
Smoking status
	Smoking status at diagnosis was documented. Patients were classified as never smokers, current smokers or former smokers
Education level
	Patients were classified in two groups; low education (Lower general education; Lower vocational education; General secondary education; Vocational secondary education; Did not finish primary school) and high education (Pre-university secondary education; Vocational post-secondary education; University)
Disease behavior	Disease behavior is reported if it occurred at any point in the disease course up to baseline.
Fistulising disease	Fistulising disease is confirmed by physical examination, radiological or endoscopy assessment.
Stricturing disease	A stricture had to be symptomatic. An anal stenosis had to be symptomatic and confirmed by physical examination.
Penetrating disease	Penetrating disease is defined as an intestinal abscess or intestinal perforation due to disease activity.
Prescribed medication
Anti-tumor necrosis factor alpha	Prescribed medication included anti-tumor necrosis factor alpha (TNF-alpha) agents (infliximab, adalimumab or certolizumab). Data on medication use was available for the entire disease course; medication use was therefore defined as medication ‘ever used’
Immunomodulators	immunomodulators (mercaptopurine, azathioprine, thioguanine or methotrexate). Data on medication use was available for the entire disease course; medication use was therefore defined as medication ‘ever used’
IBD-related surgical interventions
	IBD-related surgical interventions included small bowel resection, ileocecal resection, colon resection, resection other, strictureplasty, ileostomy/colostomy, surgery for abscesses or fistula, stoma and pouch
Extra-intestinal manifestations
Skin manifestations	Skin manifestations unrelated to the use of IBD medication such as pyoderma gangrenosum, erythema nodosum, hidradenitis suppurativa, psoriasis or palmoplantar psoriasiform pustolosis, and metastatic CD.
Musculoskeletal manifestations	Arthritis was defined as red and swollen joints, dactylitis, reactive arthritis and gout. Arthropathy was defined as painful joints, without any swelling or redness, with an inflammatory pattern: pain at night or at rest (e.g., sacroiliitis, ankylosing spondylitis, enthesitis, and inflammatory back pain).
Ocular manifestations	Ocular manifestations included uveitis and episcleritis.
Complications
Osteopenia	Osteopenia was defined as a bone mineral density T-score lower than -1.
Thromboembolic event	A thromboembolic event was confirmed by additional tests (radiology, endoscopy or histology).

IBD: Inflammatory bowel disease; CD: Crohn’s disease; UC: Ulcerative colitis.

Table 2 Demographic and clinical characteristics in patients with Crohn’s disease and ulcerative colitis n (%)

	CD	UC	P value
n	1740	1054
Sex (female)	1103 (63)	561 (53)	< 0.01
Median age, yr, (IQR 25-75)	39.9 (30-51)	43.4 (33-53)	< 0.01
Median age diagnosis, yr, (IQR 25-75)	24.1 (19-32)	29.0 (22-39)	< 0.01
Median age disease duration, yr, (IQR 25-75)	11.7 (6-21)	10.3 (5-18)	< 0.01
Family history of IBD1	518 (30)	266 (25)	0.01
Appendectomy1	266 (15)	70 (7)	< 0.01
Smoking	1620 (100)	984 (100)
Yes	439 (27)	117 (12)	< 0.01
Disease location
L1: ileal disease2	324 (22)
L2: colon disease2	450 (31)
L3: ileocolon disease2	696 (47)
L4: upper GI disease1	156 (9)
P: peri-anal disease1	485 (28)
E1: proctitis3		77 (8)
E2: left-sided colitis3		315 (34)
E3: extensive colitis3		541 (58)
Disease behavior CD
Fistulising disease1	289 (17)
Penetrating disease1	232 (13)
Stricturing disease1	445 (26)
Education	1708 (100)	1036 (100)
Low	932 (55)	517 (50)	0.02
Employment status
Full-time	607 (35)	440 (42)	< 0.01
Part-time	359 (21)	224 (21)
Partially disabled to work	129 (7)	54 (5)
Fully disabled to work	342 (20)	124 (12)
Sick leave	77 (4)	36 (3)
Retired	22 (1.3)	21 (2)
Other	204 (12)	155 (15)

¹Missing values were scored as non-present;

²These percentages are calculated for 1470 patients with CD;

³These percentages are calculated for 993 patients with UC. CD: Crohn’s disease; UC: Ulcerative colitis.

Table 3 Univariate and multivariate regression analyses of work disability in patients with Crohn’s disease n (%)

	Work disability	Employed	Unadj. OR (95%CI)	Adj. OR (95%CI)
n	548 (100)	966 (100)
Sex (female)	397 (72)	556 (58)	1.94 (1.55-2.43)	2.03 (1.53-2.69)
Age, yr
< 40	215 (39)	537 (55)	1.00	1.00
40-55	220 (40)	335 (35)	1.64 (1.30-2.07)	0.94 (0.65-1.35)
> 55	113 (21)	94 (10)	3.00 (2.19-4.12)	1.63 (0.95-2.77)
Age at diagnosis, yr
A1: diagnosis ≤ 16	47 (9)	156 (16)	1.00	1.00
A2: diagnosis 17-40	413 (75)	719 (75)	1.91 (1.35-2.70)	2.02 (1.30-3.13)
A3: diagnosis > 40	88 (16)	91 (9)	3.21 (2.07-4.98)	3.69 (1.83-7.42)
Disease duration, yr
≤ 15	285 (52)	618 (64)	1.00	1.00
> 15	263 (48)	348 (36)	1.64 (1.32-2.03)	1.67 (1.15-2.43)
Education	537 (100)	950 (100)
Low	366 (68)	446 (47)	2.42 (1.94-3.02)	2.02 (1.55-2.64)
Smoking	508 (100)	904 (100)
Yes	180 (35)	203 (22)	1.90 (1.49-2.41)	1.45 (1.09-1.92)
Disease location
L1: ileal disease1	88 (19)	184 (23)	1.00	1.00
L2: colon disease1	138 (30)	263 (33)	1.10 (0.79-1.52)	1.10 (0.75-1.61)
L3: ileocolon disease1	237 (51)	359 (44)	1.38 (1.02-1.87)	1.29 (0.91-1.83)
L4: upper GI disease2	52 (9)	82 (8)	1.13 (0.79-1.63)	-
P: peri-anal disease2	170 (31)	256 (26)	1.25 (0.99-1.57)	1.03 (0.77-1.37)
Disease behavior CD
Fistulising disease2	95 (17)	156 (16)	1.09 (0.82-1.44)	-
Stricturing disease2	145 (26)	248 (26)	1.04 (0.82-1.32)	-
Penetrating disease2	72 (13)	128 (13)	0.99 (0.73-1.35)	-
Pouch2	12 (2)	17 (1.8)	1.25 (0.59-2.64)	-
Stoma2	96 (18)	108 (11)	1.69 (1.25-2.27)	1.15 (0.78-1.69)
Surgery2	288 (53)	406 (42)	1.53 (1.24-1.89)	1.48 (1.10-2.00)
Medication	537 (100)	949 (100)
Anti-TNFα	309 (58)	435 (46)	1.60 (1.29-1.98)	1.86 (1.43-2.43)
Immunomodulators	395 (74)	698 (74)	1.00 (0.79-1.27)	-
Extra-intestinal manifestations2	229 (42)	294 (30)	1.64 (1.32-2.04)	1.36 (1.05-1.77)
PSC2	7 (1.3)	14 (1.5)	0.88 (0.35-2.19)	-
Complications2	155 (28)	223 (23)	1.31 (1.04-1.67)	1.18 (0.88-1.59)

¹These percentages are calculated for 463 patients with CD that were disabled for work and 806 patients with CD that were employed;

²Missing values were scored as non-present. CD: Crohn’s disease; Unadj: Unadjusted; TNFα: Tumor necrosis factor alpha; PSC: Primary sclerosing cholangitis.

Table 4 Univariate and multivariate regression analyses of full and partial work disability in patients with Crohn’s disease n (%)

	Full disability	Partial disability	Unadj. OR (95%CI)	Adj. OR (95%CI)
n	342 (100)	129 (100)
Sex (female)	251 (73)	100 (78)	0.80 (0.50-1.29)	-
Age
< 40 yr	110 (32)	54 (42)	1.00	1.00
40-55 yr	137 (40)	61 (47)	1.10 (0.71-1.72)	1.05 (0.65-1.70)
> 55 yr	95 (28)	14 (11)	3.33 (1.74-6.37)	3.06 (1.54-6.07)
Age at diagnosis
A1: diagnosis ≤ 16 yr	28 (8)	13 (10)	1.00	-
A2: diagnosis 17-40 yr	256 (75)	103 (80)	1.15 (0.58-2.32)
A3: diagnosis > 40 yr	58 (17)	13 (10)	2.07 (0.85-5.05)
Disease duration
≤ 15 yr	151 (44)	65 (50)	1.00	-
> 15 yr	191 (56)	64 (50)	1.28 (0.86-1.93)
Education	332 (100)	128 (100)
Low	236 (71)	73 (57)	1.85 (1.21-2.83)	1.62 (1.02-2.58)
Smoking	323 (100)	115 (100)
Yes	125 (39)	33 (29)	1.57 (0.99-2.49)	1.53 (0.93-2.50)
Disease location
L1: ileal disease1	56 (19)	21 (19)	1.00	-
L2: colon disease1	80 (28)	38 (35)	0.79 (0.42-1.49)
L3: ileocolon disease1	155 (53)	50 (46)	1.16 (0.64-2.11)
L4: upper GI disease2	38 (11)	8 (6)	1.89 (0.86-4.17)	-
P: peri-anal disease2	109 (32)	45 (35)	0.87 (0.57-1.34)	-
Disease behavior CD
Fistulising disease2	64 (19)	23 (18)	1.06 (0.63-1.80)	-
Stricturing disease2	92 (27)	33 (26)	1.07 (0.67-1.70)	-
Penetrating disease2	47 (14)	19 (15)	0.92 (0.52-1.64)	-
Pouch2	6 (1.8)	4 (3)	0.56 (0.15-2.01)	-
Stoma2	69 (20)	20 (16)	1.38 (0.80-2.38)	-
Surgery2	192 (56)	64 (50)	1.30 (0.87-1.95)	-
Medication	335 (100)	125 (100)
Anti-TNFα	193 (58)	68 (54)	1.14 (0.75-1.72)	-
Immunomodulators	249 (74)	87 (70)	1.26 (0.80-1.99)	-
Extra-intestinal manifestations2	152 (44)	50 (39)	1.26 (0.84-1.91)	-
PSC2	2 (0.6)	4 (3)	0.18 (0.03-1.02)	0.19 (0.03-1.10)
Complications2	106 (31)	34 (26)	1.25 (0.80-1.98)	-

¹These percentages are calculated for 291 patients with CD that were fully disabled and 109 patients with CD that were partially disabled;

²Missing values were scored as non-present. CD: Crohn’s disease; Unadj: Unadjusted; TNFα: Tumor necrosis factor alpha; PSC: Primary sclerosing cholangitis.

Table 5 Univariate and multivariate regression analyses of work disability in patients with ulcerative colitis n (%)

	Work disability	Employed	Unadj. OR (95%CI)	Adj. OR (95%CI)
n	214 (100)	664 (100)
Sex (female)	124 (58)	333 (50)	1.37 (1.00-1.87)	1.76 (1.23-2.53)
Age
< 40 yr	58 (27)	287 (43)	1.00	1.00
40-55 yr	94 (44)	277 (42)	1.68 (1.16-2.42)	1.52 (0.97-2.40)
> 55 yr	62 (29)	100 (15)	3.07 (2.01-4.69)	2.93 (1.68-5.14)
Age at diagnosis
A1: diagnosis ≤ 16 yr	18 (8)	64 (10)	1.00	1.00
A2: diagnosis 17-40 yr	124 (58)	474 (71)	0.93 (0.53-1.63)	1.06 (0.55-2.04)
A3: diagnosis > 40 yr	72 (34)	126 (19)	2.03 (1.12-3.69)	1.99 (0.92-4.28)
Disease duration
≤ 15 yr	129 (60)	439 (66)	1.00	-
> 15 yr	85 (40)	225 (34)	1.29 (0.94-1.77)
Education	208 (100)	656 (100)
Low	144 (69)	282 (43)	2.98 (2.14-4.16)	2.59 (1.81-3.70)
Smoking	206 (100)	621 (100)
Yes	30 (15)	71 (11)	1.32 (0.83-2.09)	-
Disease location
E1: proctitis1	14 (7)	54 (9)	1.00	-
E2: left-sided colitis1	54 (27)	215 (37)	97 (0.50-1.87)
E3: extensive colitis1	130 (66)	317 (54)	1.58 (0.85-2.95)
Pouch2	37 (17)	54 (8)	2.36 (1.50-3.71)	1.72 (0.81-3.65)
Stoma2	35 (16)	54 (8)	2.21 (1.40-3.49)	1.13 (0.54-2.38)
Surgery2	60 (28)	97 (15)	2.28 (1.58-3.29)	1.68 (0.75-3.75)
Medication	211 (100)	649 (100)
Anti-TNFα	53 (25)	120 (18)	1.48 (1.02-2.14)	1.33 (0.86-2.06)
Immunomodulators	139 (66)	350 (54)	1.65 (1.19-2.28)	1.58 (1.09-2.28)
Extra-intestinal manifestations2	78 (36)	130 (20)	2.36 (1.68-3.30)	2.13 (1.47-3.09)
PSC2	8 (4)	21 (3)	1.19 (0.52-2.73)	-
Complications2	37 (17)	89 (13)	1.35 (0.89-2.05)	-

¹These percentages are calculated for 198 patients with UC that were disabled for work and 586 patients with UC that were employed;

²Missing values were scored as non-present. UC: Ulcerative colitis; Unadj: Unadjusted; Adj: Adjusted; TNFα: Tumor necrosis factor alpha; PSC: Primary sclerosing cholangitis.

Table 6 Univariate and multivariate regression analyses of full and partial work disability in patients with ulcerative colitis n (%)

	Full disability	Partial disability	Unadj. OR (95%CI)	Adj. OR (95%CI)
n	124 (100)	54 (100)
Sex (female)	75 (60)	26 (48)	1.65 (0.87-3.14)	-
Age
< 40 yr	25 (20)	15 (28)	1.00	1.00
40-55 yr	52 (42)	32 (59)	0.98 (0.45-2.12)	0.90 (0.40-2.03)
> 55 yr	47 (38)	7 (13)	4.03 (1.45-11.17)	3.49 (1.23-9.92)
Age at diagnosis
A1: diagnosis ≤ 16 yr	7 (6)	5 (9)	1.00	-
A2: diagnosis 17-40 yr	70 (56)	34 (63)	1.47 (0.43-4.97)
A3: diagnosis > 40 yr	47 (38)	15 (28)	2.24 (0.62-8.10)
Disease duration
≤ 15 yr	65 (52)	36 (67)	1.00	1.00
> 15 yr	59 (48)	18 (33)	1.82 (0.93-3.54)	1.78 (0.87-3.62)
Education	122 (100)	50 (100)
Low	84 (69)	37 (74)	0.78 (0.37-1.63)	-
Smoking	121 (100)	52 (100)
Yes	18 (15)	7 (13)	1.12 (0.44-2.88)	-
Disease location
E1: proctitis1	9 (8)	4 (8)	1.00	-
E2: left-sided colitis1	39 (33)	9 (18)	1.93 (0.48-7.68)	-
E3: extensive colitis1	70 (59)	38 (74)	0.82 (0.24-2.84)	-
Pouch2	24 (19)	9 (17)	1.20 (0.52-2.79)	-
Stoma2	23 (19)	8 (15)	1.31 (0.54-3.15)	-
Surgery2	37 (30)	14 (26)	1.22 (0.59-2.50)	-
Medication	122 (100)	53 (100)
Anti-TNFα	30 (25)	10 (19)	1.40 (0.63-3.13)	-
Immunomodulators	77 (63)	37 (70)	0.74 (0.37-1.48)	-
Extra-intestinal manifestations2	51 (41)	19 (35)	1.29 (0.66-2.50)	-
PSC2	3 (2)	4 (7)	0.31 (0.07-1.44)	-
Complications2	28 (23)	4 (7)	3.65 (1.21-10.97)	3.39 (1.09-10.58)

¹These percentages are calculated for 118 patients with UC that were fully disabled and 51 patients with UC that were partially disabled;

²Missing values were scored as non-present. UC: Ulcerative colitis; Unadj: Unadjusted; Adj: Adjusted; TNFα: Tumor necrosis factor alpha; PSC: Primary sclerosing cholangitis.