Internet-based data inclusion in a population-based European collaborative follow-up study of inflammatory bowel disease patients: Description of methods used and analysis of factors influencing response rates

Table 1 Cumulative number of IBD (CD+UC) patients per center followed-up or lost to follow-up for ePQ and ePpPFU. Centers indicated in gray had not reached the 60% response rate threshold

Center	Total number of CD+ CU patients	EPQ response (%)	EPQ response without deaths and No IBD %	Reason for non response EPQ					PpPFU response (%)	PpPFU response without No IBD %	Reason for non response PpPFU				EPQ ànd PpPFU (%)
				Not willing	Untrace- able	No IBD	Death	Not started			Not willing	Untrace- able	No IBD	Not started
Beer Sheeva	60	41 (68)	76	5	8	3	3	0	46 (77)	77	3	11	0	0	42 (70)
Copenhagen	147	103 (70)	84	12	7	0	25	0	132 (90)	90	6	9	0	0	120 (82)
Cremona	51	35 (68)	76	4	7	0	5	0	43 (84)	84	1	7	0	0	40 (78)
Heraklion	62	38 (61)	68	2	13	0	5	4	49 (79)	79	3	17	0	0	40 (65)
Ioannina	43	36 (84)	88	2	3	0	2	0	39 (91)	91	0	4	0	0	38 (88)
Oslo	378	226 (60)	69	65	34	6	45	2	332 (88)	89	21	25	1	0	271 (72)
Reggio Emilia	84	61 (73)	79	4	12	0	7	0	69 (82)	82	5	11	0	0	68 (81)
S-Limburg	216	156 (72)	76	28	20	0	11	1	194 (90)	90	0	23	0	0	159 (74)
Vigo	100	73 (73)	77	4	18	0	5	0	81 (81)	81	3	16	0	0	77 (77)
SUBTOTAL	1 141	769 (67	75	126	122	9	108	7	985 (86)	86	42	123	1	0	855 (75)
Almada	21	11 (52)	58	1	7	0	2	0	12 (57)	57	0	9	0	0	11 (52)
Dublin	186	57 (30)	34	10	58	3	17	41	80 (43)	43	1	26	2	78	56 (30)
Firenze	115	48 (42)	42	0	0	0	0	67	39 (34)	34	0	4	0	72	36 (31)
Milano	42	19 (45)	58	1	6	0	9	7	0 (0)	0	0	0	0	42	0 (0)
SUBTOTAL	364	135 (37)	41	12	71	3	28	115	131 (36)	36	1	39	2	192	103 (28)
Total	1 505	904 (60)	67	138	193	12	136	122	1 116 (74)	74	43	162	3	192	958 (64)

Table 2 Number of CD patients per center followed-up or lost to follow-up for ePQ and ePpPFU. Centers indicated in gray had not reached the 60% response rate threshold

Center	Total number of CD patients	EPQ response (%)	EPQ response without deaths and No IBD %	Reason for non response EPQ					PpPFU response (%)	PpPFU response without No IBD %	Reason for non response PpPFU				EPQ ànd PpPFU (%)
				Not willing	Untrace-able	No IBD	Death	Not started			Not willing	Untrace- able	No IBD	Not started
Almada	13	8 (62)	67	0	4	0	1	0	8 (62)	62	0	5	0	0	8 (62)
Beer Sheeva	21	13 (62)	72	2	3	2	1	0	15 (71)	71	1	5	0	0	14 (67)
Copenhagen	58	41 (71)	85	5	2	0	10	0	52 (90)	90	6	0	0	0	47 (81)
Cremona	10	7 (70)	78	2	0	0	1	0	9 (90)	90	1	0	0	0	8 (80)
Heraklion	14	7 (50)	70	0	3	0	3	1	11 (79)	79	0	5	0	0	9 (64)
Ioannina	6	4 (67)	80	0	1	1	1	0	5 (83)	83	0	1	0	0	5 (83)
Oslo	110	69 (63)	70	15	13	0	11	1	97 (88)	89	4	8	1	0	79 (73)
Reggio Emilia	34	24 (71)	77	0	7	0	3	0	27 (79)	79	1	6	0	0	27 (79)
S-Limburg	77	60 (78)	82	8	5	0	4	0	69 (90)	90	0	8	0	0	61 (79)
Vigo	35	27 (77)	84	1	4	0	3	0	30 (86)	86	1	4	0	0	30 (86)
SUBTOTAL	378	260 (69)	77	33	42	3	38	2	323 (85)	85	14	42	1	0	288 (76)
Dublin	63	17 (27)	30	2	25	2	5	12	25 (40)	40	0	6	1	31	17 (27)
Firenze	29	13 (45)	45	0	0	0	0	16	13 (45)	45	0	1	0	15	11 (38)
Milano	13	4 (31)	50	0	2	0	5	2	0 (0)	0	0	0	0	13	0 (0)
SUBTOTAL	105	34 (32)	36	2	27	2	10	30	38 (36)	37	0	7	1	59	28 (27)
TOTAL	483	294 (61)	69	35	69	5	48	32	361 (75)	75	14	49	2	59	316 (65)

Table 3 Number of UC patients per center followed-up or lost to follow-up for ePQ and ePpPFU. Centers indicated in gray had not reached the 60% response rate threshold

Center	Total number of CD patients	EPQ response (%)	EPQ response without deaths and No IBD %	Reason for non response EPQ					PpPFU response (%)	PpPFU response without No IBD %	Reason for non response PpPFU				EPQ ànd PpPFU (%)
				Not willing	Untrace-able	No IBD	Death	Not started			Not willing	Untrace- able	No IBD	Not started
Beer Sheeva	39	28 (72)	78	3	5	1	2	0	31 (79)	79	2	6	0	0	28 (72)
Copenhagen	89	62 (70)	84	7	5	0	15	0	80 (90)	90	0	9	0	0	73 (82)
Cremona	41	28 (68)	76	2	7	0	4	0	34 (83)	83	0	7	0	0	32 (78)
Heraklion	48	31 (65)	67	2	10	0	2	3	38 (79)	79	3	12	0	0	31 (65)
Ioannina	37	32 (86)	89	2	2	0	1	0	34 (92)	92	0	3	0	0	33 (89)
Oslo	268	157 (59)	69	50	21	5	34	1	235 (88)	88	17	17	0	0	192 (72)
Reggio Emilia	50	37 (74)	80	4	5	0	4	0	42 (84)	84	4	5	0	0	41 (82)
S-Limburg	139	96 (69)	72	20	15	0	7	1	125 (90)	90	0	15	0	0	98 (71)
Vigo	65	46 (70)	73	3	14	0	2	0	51 (78)	78	2	12	0	0	47 (72)
SUBTOTAL	776	517 (67)	74	93	84	6	71	5	670 (86)	86	28	86	0	0	575 (74)
Almada	8	3 (38)	50	1	3	0	1	0	4 (50)	50	0	4	0	0	3 (38)
Dublin	123	40 (33)	36	8	33	1	12	29	55 (45)	45	1	20	1	47	39 (32)
Firenze	86	35 (41)	41	0	0	0	0	51	26 (30)	30	0	3	0	57	25 (29)
Milano	29	15 (51)	60	1	4	0	4	5	0 (0)	0	0	0	0	29	0 (0)
SUBTOTAL	246	93 (38)	41	10	40	1	17	85	85 (35)	35	1	27	1	133	67 (27)
TOTAL	1 022	610 (60)	67	103	124	7	88	90	755 (74)	74	29	113	1	133	642 (63)

Table 4 Results of univariate and multivariate logistic regression analyses for identification of predictors of ePQ completion in the entire cohort

CD+UC
N total = 1 141	n	Response (%)	Unadjusted Odds Ratio (95%CI)	Adjusted Odds Ratio (95%CI)	P
CD/UC	365/776	289 (79)/588 (76)	1.22 (0.90-1.64)	1.24 (0.91-1.70)	0.171
Female/male	552/589	429 (77)/448 (76)	1.10 (0.84-1.44)	1.09 (0.82-1.44)	0.564
Age at ePQ completion	707/434	559 (79)/318 (73)	1.38 (1.04-1.82)	1.53 (1.14-2.05)	0.004
>40/ ≤40 yr
Flare/no flare1	88/1 053	80 (91)/797 (76)	3.21 (1.53-6.73)	3.32 (1.57- 7.03)	0.002

¹Flare within 3 mo period previous of the moment of ePQ completion. N: number of patients; CI: confidence interval.

Table 5 Results of univariate and multivariate logistic regression analyses for identification of predictors of ePQ completion in the UC population separately

UC
N total = 776	n	Response (%)	Unadjusted Odds Ratio (95%CI)	Adjusted Odds Ratio (95%CI)	P
Female/male	370/406	280 (76)/308 (76)	0.99 (0.71-1.38)	1.01 (0.72-1.42)	0.956
Age at ePQ completion	520/256	409 (78)/179 (70)	1.59 (1.13-2. 23)	1.70 (1.19-2.41)	0.003
>40/ ≤40 yr
Flare/no flare1	55/721	48 (87)/540 (75)	2.30 (1.02-5.17)	2.35 (1.03-5.37)	0.043
Left sided/rectum	333/221	252 (76)/169 (77)	0.96 (0.64-1.43)	0.99 (0.65-1.51)	0.965
Pancolitis/rectum	185/221	140 (76)/169 (77)	0.96 (0.61-1.51)	1.04 (0.65- 1.67)	0.875
Unknown/rectum	37/221	27 (73)/169 (77)	0.83 (0.38-1.83)	0.71 (0.31-1.64)	0.426

¹Flare within 3 mo period previous of the moment of ePQ completion. N: number of patients; CI: confidence interval; Left sided: rectum and sigmoid and/or descending colon; Unknown: unknown disease location.

Table 6 Results of univariate and multivariate logistic regression analyses for identification of predictors of ePQ completion in the CD population separately

CD
N total = 378	n	Response (%)	Unadjusted Odds Ratio (95%CI)	Adjusted Odds Ratio (95%CI)	P
Female/male	190/188	154 (81)/144 (77)	1.31 (0.80-2.15)	1.35 (0.79-2.30)	0.270
Age at ePQ completion	196/182	156 (80)/142 (78)	1.10 (0.67-1.80)	1.34 (0.79-2.30)	0.281
>40/ ≤40 yr
Flare/no flare1	34/344	33 (97)/265 (77)	9.84 (1.32-73.1)	10.9 (1.43-82.4)	0.021
Ileo colon/upper	136/20	110 (81)/16 (80)	1.06 (0.33-3.42)	0.91 (0.26-3.19)	0.879
Ileum/upper	54/20	41 (76)/16 (80)	0.79 (0.22-2.78)	0.95 (0.27-3.35)	0.631
Colon/upper	153/20	122 (80)/16 (80)	0.98 (0.31-3.15)	0.71 (0.18-2.77)	0.622
Unknown/upper	15/20	9 (60)/16 (80)	0.38 (0.083-1.69)	0.38 (0.075-1.90)	0.237

¹Flare within 3 mo period previous of the moment of ePQ completion. n: number of patients; CI: confidence interval; Upper: esophagus and/or stomach and/or duodenum and/or jejunum; Unknown: unknown disease location.