Evaluation of an educational telephone intervention strategy to improve non-screening colonoscopy attendance: A randomized controlled trial

Table 1 Baseline characteristics of the patients

	Intervention (n = 738)	Control (n = 746)	P value
Demographic variables
Age (yr), mean (SD)	59.1 (16.2)	59.9 (16.0)	0.307
Male sex, n (%)	347 (47)	363 (48.7)	0.527
Foreign nationality, n (%)	94 (12.7)	102 (13.7)	0.594
Advanced studies, n (%)	148 (20.1)	149 (20.0)	0.834
Language barrier, n (%)	67 (9.1)	53 (7.1)	0.163
Clinical variables
BMI, mean (SD)	26.7 (4.7)	26.9 (4.6)	0.657
Diabetes mellitus, n (%)	126 (17.1)	125 (16.8)	0.871
Abdominal/pelvic surgery, n (%)	287 (38.9)	292 (39.1)	0.920
Constipation, n (%)	148 (20.1)	161 (21.6)	0.469
Anxiety-depression syndrome, n (%)	253 (34.3)	253 (33.9)	0.881
Disabled condition, n (%)	29 (3.9)	33 (4.4)	0.634
Charlson index, mean (SD)	0.5 (0.9)	0.5 (0.9)	0.322
ASA classification III-IV, n (%)	84 (11.4)	100 (13.4)	0.237
High comorbidity burden, n (%)	33 (4.5)	42 (5.6)	0.308
Antiaggregants, n (%)
Aspirin	73 (9.9)	72(9.7)	0.798
Clopidogrel	6 (0.8)	9 (1.2)
Dual APA	1 (0.1)	2 (0.3)
VKA, n (%)	24 (3.3)	28 (3.8)	0.600
DOAC, n (%)
Rivaroxaban	4 (0.5)	4 (0.5)	0.735
Apixaban	8 (1.1)	(1.2)
Dabigatran	3 (0.4)	5 (0.7)
Endoscopic variables
Previous endoscopy, n (%)	335 (45.4)	323 (49.1)	0.417
Previous non-attendance, n (%)	77 (10.4)	86 (11.5)	0.500
Referring physician, n (%)
Primary care	668 (90.5)	684 (91.7)	0.128
Gastroenterologist	70 (9.5)	62 (8.3)
Indication, n (%)
Surveillance	211 (28.6)	197 (26.4)	0.620
Diagnostic	456 (61.8)	(63.3)
Family history of CRC	71 (9.6)	77 (10.3)
Waiting time (d), mean (SD)	60.7 (56.6)	59.5 (60.9)	0.701
Afternoon timetable, n (%)	467 (63.3)	746 (67.3)	0.104
Laxative, n (%)
MCSP	102 (15.1)	80 (12.5)	0.372
PEG + ascorbate, 2 L	158 (23.4)	3.2)
PEG, 4 L	416 (61.5)	411 (64.3)
Previous cleansing problems, n (%)	37 (5)	44 (5.9)	0.453

BMI: Body mass index; ASA classification: American Society of Anaesthesiologists classification; APA: Antiplatelet agent; VKA: Vitamin K antagonist; DOAC: Direct oral anticoagulant; CRC: Colorectal cancer; MCPS: Magnesium citrate plus sodium picosulfate; PEG: Polyethylene glycol.

Table 2 Bivariable analysis of risk factors for non-attendance

	ITT			PP
	A	NA	P value	A	NA	P value
Demographic risk factors
Group, n (%)			< 0.001			< 0.001
Intervention	676 (51.4)	62 (36.7)		586 (47.8)	27 (20.1)
Control	639 (48.6)	107 (63.3)		639 (52.2)	107 (79.9)
Age (yr), mean (SD)	60.2 (15.7)	54.2 (18.0)	< 0.001	60.62 (15.6)	53.45 (18.2)	< 0.001
Sex, n (%)			0.640			0.527
Female	683 (51.9)	91 (53.8)		626 (51.1)	75 (56)
Male	632 (48.1)	78 (46.2)		599 (48.9)	59 (44)
Nationality, n (%)			< 0.001			< 0.001
Spanish	1169 (88.9)	119 (70.4)		1092 (89.1)	96 (71.6)
Foreign	146 (11.1)	50 (29.6)		133 (10.9)	38 (28.4)
Studies, n (%)			< 0.001			< 0.001
Non-advanced	1033 (78.6)	154 (91.1)		947 (77.3)	121 (90.3)
Advanced	282 (21.4)	15 (8.9)		278 (22.7)	13 (9.7)
Language barrier, n (%)			0.318			0.276
No	1212 (92.2)	152 (89.9)		1130 (92.2)	120 (89.6)
Yes	103 (7.8)	17(10.1)		95 (7.8)	14 (10.4)
Clinical risk factors
BMI, mean (SD)	26.73 (4.6)	27.76 (4.9)	0.007	26.75 (4.5)	27.84 (4.9)	0.010
Diabetes mellitus, n (%)			0.758			0.528
No	1094 (83.2)	139 (82.2)		1014 (82.8)	108 (80.6)
Yes	221 (16.8)	30 (17.8)		211 (17.2)	26 (19.4)
Abdominal/pelvic surgery, n (%)			0.046			0.465
No	790 (60.1)	115 (60.8)		728 (59.4)	84 (62.7)
Yes	525 (39.9)	54 (32.0)		497 (40.6)	50 (37.3)
Constipation, n (%)			0.148			0.214
No	1034 (78.6)	141 (83.4)		958 (78.2)	11 (82.8)
Yes	429 (32.6)	77 (45.6)		276 (21.8)	23 (17.2)
Anxiety-depression syndrome, n (%)			0.001			0.002
No	886 (67.4)	92 (54.4)		832 (67.9)	73 (54.5)
Yes	429 (32.6)	77 (45.6)		393 (32.1)	61 (45.5)
Disabled condition, n (%)			< 0.001			0.002
No	1269 (96.5)	153 (90.5)		1182 (96.5)	122 (91.0)
Yes	46 (3.5)	16 (9.5)		43 (3.5)	12 (9.0)
Charlson index, mean (SD)	0.57 (0.9)	0.54 (0.9)	0.771	0.57 (0.9)	0.50 (0.8)	0.403
ASA classification, n (%)			0.813			0.834
I/II	1151 (87.5)	149 (88.2)		1071 (87.4)	118 (88.1)
III/IV	164 (12.5)	20 (11.8)		154 (12.6)	16 (11.9)
High comorbidity burden, n (%)			0.840			0.769
No	1248 (94.9)	161 (95.3)		1163 (94.9)	128 (95.5)
Yes	67 (5.1)	8 (4.7)		62 (5.1)	6 (4.5)
Endoscopic risk factors
Previous endoscopy, n (%)			< 0.001			< 0.001
No	697 (53)	129 (76.3)		646 (52.7)	98 (73.1)
Yes	618 (47)	40 (23.7)		579 (47.3)	36 (26.9)
Previous non-attendance, n (%)			< 0.001			< 0.001
No	1192 (90.6)	129 (76.3)		1111 (90.7)	101 (75.4)
Yes	123 (9.4)	40 (23.7)		114 (9.3)	33 (24.6)
Referring physician, n (%)			0.125			0.293
Primary care	1178 (89.6)	159 (94.1)		1101 (89.9)	125 (93.3)
Gastroenterologist	122 (9.3)	10 (5.9)		109 (8.9)	9 (6.7)
Other specialities	15 (1.1)	0 (0.0)		15 (1.2)	0 (0)
Indication, n (%)			< 0.001			< 0.001
Surveillance	338 (29.5)	20 (11.8)		357 (29.1)	15 (11.2)
Diagnostic	793 (60.3)	135 (79.9)		744 (60.7)	107 (79.9)
Family history of CRC	134 (10.2)	14 (8.3)		124 (10.1)	12 (9)
Waiting time (d), mean (SD)	59.3 (57.4)	66.2 (68.6)	0.149	58.3 (55.0)	66.1 (72.4)	0.134
Endoscopy timetable, n (%)			0.030			0.029
Morning	469 (35.7)	46 (27.2)		436 (35.6)	35 (26.1)
Afternoon	846 (64.3)	123 (72.8)		789 (64.4)	99 (73.9)
Previous cleansing problems, n (%)			0.318			0.180
No	1246 (94.8)	157 (92.9)		1159 (94.6)	123 (91.8)
Yes	69 (5.2)	12 (7.1)		66 (5.4)	11 (8.2)

ITT: Intention-to-treat analysis; PP: Per protocol analysis; A: Attendance; NA: Non-attendance; BMI: Body mass index; ASA classification: American Society of Anaesthesiologists classification; CRC: Colorectal cancer.

Table 3 Multivariable analysis of risk factors for non-attendance

	ITT			PP
	OR	95%CI	P value	OR	95%CI	P value
Demographic risk factors
Group
Intervention	1			1
Control	1.81	1.27-2.58	0.001	3.56	2.25-5.64	< 0.001
Age	0.98	0.97-0.99	< 0.001	0.97	0.96-0.98	< 0.001
Nationality
Spanish	1
Foreign	2.69	1.77-4.10	< 0.001	2.49	1.55-4.00	< 0.001
Studies level
Non-advanced	1			1
Advanced	0.47	0.27-0.83	0.010	0.51	0.27-0.94	0.031
Clinical risk factors
BMI	1.05	1.01-1.08	0.012	1.04	1.01-1.09	0.027
Anxiety-depression syndrome
No	1			1
Yes	2.00	1.40-2.86	< 0.001	2.02	1.35-3.02	0.001
High comorbidity burden
No	1			1
Yes	2.82	0.86-9.24	0.087	3.87	1.17-12.85	0.027
Disabled condition
No	1			1
Yes	3.39	1.68-6.84	0.001	3.37	1.50-7.58	0.003
Endoscopic risk factors
Previous endoscopy
No	1			1
Yes	0.35	0.22-0.56	< 0.001	0.46	0.28-0.77	0.003
Previous non-attendance
No	1			1
Yes	2.94	1.89-4.58	< 0.001	3.13	1.91-5.13	< 0.001
Previous cleansing problems
No	1			1
Yes	2.58	1.19-5.59	0.016	2.58	1.13-5.85	0.024
Endoscopy timetable
Morning	1			1
Afternoon	1.52	1.03-2.23	0.033	1.62	1.04-2.51	0.031

ITT: Intention-to-treat analysis; PP: Per protocol analysis; BMI: Body mass index; OR: Odds ratio; CI: Confidence interval.

Table 4 Compliance, rescheduling and patient satisfaction questionnaire

	Intervention	Control	P value
Compliance outcomes
Fasting 2-4 h, n/n (%)
ITT	464/702 (66.2)	427/720 (59.3)	0.007
PP	408/583 (70.1)	427/720 (59.3)	< 0.001
Split regimen, n/n (%)
ITT	622/702 (88.6)	572/719 (79.6)	< 0.001
PP	544/583 (93.3)	572/719 (79.6)	< 0.001
Correct diet, n/n (%)
ITT	633/702 (90.2)	593/720 (82.4)	< 0.001
PP	553/583 (94.9)	593/720 (82.4)	< 0.001
Complete intake, n/n (%)
ITT	597/702 (85)	554/720 (76.9)	< 0.001
PP	522/583 (89.5)	554/720 (76.9)	< 0.001
Cleansing compliance, n/n (%)
ITT	433/702 (61.7)	379/720 (52.6)	0.001
PP	383/583 (65.7)	379/720 (52.6)	< 0.001
Antithrombotic drugs, n/n (%)
ITT	37/40 (92.5)	27/43 (62.8)	0.001
PP	33/35 (94.3)	27/43 (62.8)	0.001
Endoscopy with anaesthesiologist, n/n (%)
ITT	26/33 (78.8)	0/42 (0)	< 0.001
PP	26/26 (100)	0/42 (0)	< 0.001
Rescheduling for non-compliance
Global rescheduling, n/n (%)
ITT	2/676 (0.3)	15/639 (2.3)	0.001
PP	1/586 (0.2)	15/639 (2.3)	0.001
Patient satisfaction questionnaire
Percentage of excellent (item 8), n/n (%)
ITT	195/382 (51)	97/373 (26)	< 0.001
PP	171/346 (49.4)	97/373 (26)	< 0.001
Information score (item 8)
ITT, mean (SD)	3.29 (0.88)	2.80 (1)	< 0.001
PP, mean (SD)	3.31 (0.89)	2.80 (1)	< 0.001
Total score of the questionnaire
ITT, mean (SD)	26.12 (3.76)	25.43 (3.82)	0.01
PP, mean (SD)	26.18 (3.87)	25.43 (3.82)	0.008

ITT: Intention-to-treat analysis; PP: Per protocol analysis.