Introduction
Colonoscopy is essential for diagnosis and treatment of acute lower gastrointestinal
bleeding (ALGIB). However, colonoscopy for ALGIB is an advanced and high-risk endoscopic
procedure, and more training and experience are needed to maintain the quality and
safety of colonoscopy for ALGIB than conventional colonoscopy. A previous retrospective
study with 403 ALGIB patients showed that performance of the colonoscopy by an expert
endoscopist was a significantly positive factor for the identification of stigmata
of recent hemorrhage (SRH) diverticula, which is an important endoscopic outcome [1]. However, no available high-quality data on the effectiveness and safety of the
performance of colonoscopies for ALGIB by nonexpert endoscopists in emergency settings
have been reported. In addition, it is necessary to evaluate the associations between
the number of years of experience and endoscopic and clinical outcomes in ALGIB patients.
The latest colonoscopy core curriculum prepared by the American Society for Gastrointestinal
Endoscopy Training Committee stated that a full discussion of the evaluation and treatment
of lower gastrointestinal bleeding was beyond the scope of the document [2].
Recently, we performed a randomized controlled trial to evaluate the efficacy and
safety of colonoscopy for ALGIB patients [3]. The trial had the largest sample size yet and was the first multicenter study involving
nearly 100 endoscopists. In the present study, we performed a post hoc analysis of
the trial data. This study was performed to investigate the feasibility of colonoscopy
by nonexpert endoscopists in ALGIB patients.
Patients and methods
Study subjects
This study is a post hoc analysis from a multicenter randomized controlled trial (RCT)
of early and elective colonoscopy for ALGIB that investigated the efficacy and safety
of the former for patients with ALGIB [3]
[4]. Briefly, this RCT was an open-label study, and 170 patients aged ≥ 20 years presenting
with moderate-to-severe hematochezia or melena within 24 hours of arrival were randomly
assigned (1:1) to either receive an early colonoscopy (within 24 hours of the initial
visit to the hospital) or an elective colonoscopy (24–96 hours after hospital admission).
The study was conducted at 15 hospitals in Japan from July 2016 until May 2018. Of
the 170 enrolled patients, a total of 162 underwent randomization; three were excluded,
and 159 were included in the modified intention-to-treat population. This post hoc
analysis was approved by the institutional review boards of all participating hospitals.
Colonoscopy and endoscopists
All endoscopists were divided into two categories: experts and nonexperts. An expert
endoscopist was defined as having conducted more than 1000 colonoscopies and as having
performed endoscopic hemostasis, with board certification from the Japanese Gastroenterological
Endoscopy Society (JGES); other endoscopists were considered nonexperts. We evaluated
the years of experience with endoscopy. The selection of nonexpert endoscopists in
an emergency setting depended on each institution's policy and patient background.
This study protocol allowed a nonexpert endoscopist to perform a colonoscopy under
the supervision of an expert endoscopist who provided verbal advice. When a nonexpert
endoscopist met with difficulties or took longer to perform the procedure and when
safety concerns for the patient arose, an expert endoscopist took over.
Colonoscopies were performed as video endoscopies (Fujifilm Corporation, Tokyo, Japan,
or Olympus Optical, Tokyo) after oral bowel preparation with 2 to 4 L polyethylene
glycol-electrolyte solution; an additional enema was allowed to be administered to
patients in the case of inadequate bowel cleansing. The quality of bowel preparation
was evaluated using the Aronchick scale [5]. The preparation quality was defined as adequate when excellent and good results
were obtained.
An attachment cap and a water-jet device were used for all colonoscopy procedures.
Attending physicians decided when to discontinue and resume medications such as nonsteroidal
anti-inflammatory drugs, antiplatelet drugs, or anticoagulants.
Endoscopic outcomes and clinical outcomes
The endoscopic outcomes were the cecum insertion rate and time, completion rate of
insertion by nonexperts alone, total procedure time, rate of identification of SRH,
success rate of endoscopic treatment, completion rate of successful endoscopic treatment
by nonexperts alone, need for additional endoscopic examinations, and colonoscopy-related
adverse events (AEs). Clinical outcomes were the need for interventional radiology,
need for surgery, need for transfusion during hospitalization, length of hospital
stay, 30-day rebleeding rate, and 30-day mortality rate. Thirty-day rebleeding was
defined as significant fresh blood in the stool after the initial colonoscopy with
any of the following: 1) hemorrhagic shock; 2) need for transfusion; 3) identification
of blood pooling on further colonoscopy; v) SRH in the lower gastrointestinal tract;
or 5) extravasation identified in the colorectal region on contrast-enhanced computed
tomography.
Statistical analysis
Continuous variables were compared using Wilcoxon's rank-sum test. Categorical variables
were compared using the χ2 test or Fisher's exact test. P value indicating statistical significance of the primary outcome was set at < 0.05
for two-tailed tests.
As a sensitivity analysis, we performed a 1:1 propensity score-weighted analysis to
balance covariates between the expert and nonexpert groups. A logistic regression
model was used to calculate propensity scores for each patient in the group, including
as covariates all of the following clinical characteristics: age, sex, body mass index,
height, weight, level of hemoglobin, systolic and diastolic blood pressures, heart
rate at admission, use of medications (NSAIDs, low-dose aspirin, thienopyridine, cilostazol,
other antiplatelet drugs, warfarin, direct oral anticoagulants), and the presence
of comorbidities (previous lower gastrointestinal bleeding, ischemic heart disease,
chronic obstructive pulmonary disease, peptic ulcer, liver cirrhosis, diabetes mellitus,
chronic heart failure, cerebrovascular disease, dementia, collagen disease, chronic
kidney disease, leukemia, malignant lymphoma, solid tumors), and allocation to the
early colonoscopy group.
As a subgroup analysis, we categorized the nonexpert group into two groups: < 3 years
of endoscopic experience and 3 to 6 years of endoscopic experience, according to the
distribution of the obtained data (data not shown). We compared endoscopic and clinical
outcomes between the group with < 3 years of endoscopic experience and the expert
group and between the group with 3 to 6 years of endoscopic experience and the expert
group.
The statistical analyses were performed with SAS software v. 9.4 (SAS Institute, Cary,
North Carolina, United States).
Results
Baseline patient characteristics
[Table 1] shows patient characteristics. The expert group performed colonoscopies in 96 patients,
and the nonexpert group performed colonoscopies in 63 patients at the 12 participating
hospitals. The expert group had a mean of 10.52 years of endoscopy experience and
the nonexpert group had a mean of 4.32 years of experience.
Table 1
Baseline patient characteristics.
|
Characteristics
|
Expert
(N = 96)
|
Nonexpert (N = 63)
|
P value
|
|
Age (years), mean ± SD
|
70.9 ± 12.9
|
69.6 ± 12.1
|
0.5383
|
|
Sex, male (%)
|
62 (64.6)
|
44 (69.8)
|
0.4915
|
|
Body mass index, mean ± SD
|
23.5 ± 4.1
|
23.3 ± 3.0
|
0.7757
|
|
Comorbidities
|
|
|
39 (40.6)
|
19 (30.2)
|
0.1799
|
|
|
1.5 ± 1.7
|
1.2 ± 1.9
|
0.2943
|
|
|
25 (26.0)
|
5 (7.9)
|
0.0043
|
|
|
2 (2.1)
|
1 (1.6)
|
0.8221
|
|
|
5 (5.2)
|
3 (4.8)
|
0.8998
|
|
|
1 (1.0)
|
2 (3.2)
|
0.3336
|
|
|
18 (18.8)
|
9 (14.3)
|
0.4634
|
|
|
8 (8.3)
|
1 (1.6)
|
0.0718
|
|
|
20 (20.8)
|
6 (9.5)
|
0.0593
|
|
|
0 (0.0)
|
2 (3.2)
|
0.0789
|
|
|
7 (7.3)
|
2 (3.2)
|
0.2718
|
|
|
13 (13.5)
|
6 (9.5)
|
0.4449
|
|
|
1 (1.0)
|
0 (0.0)
|
0.4164
|
|
|
2 (2.1)
|
0 (0.0)
|
0.2489
|
|
|
10 (10.4)
|
9 (14.3)
|
0.4619
|
|
|
1 (1.0)
|
2 (3.2)
|
0.3336
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
Medication
|
|
|
30 (31.3)
|
8 (12.7)
|
0.0073
|
|
|
11 (11.5)
|
2 (3.2)
|
0.0622
|
|
|
4 (4.2)
|
3 (4.8)
|
0.858
|
|
|
2 (2.1)
|
6 (9.5)
|
0.0358
|
|
|
9 (9.4)
|
1 (1.6)
|
0.0479
|
|
|
8 (8.3)
|
2 (3.2)
|
0.19
|
|
|
20 (20.8)
|
10 (15.9)
|
0.4343
|
|
Initial assessment
|
|
|
3 (3.1)
|
2 (3.2)
|
0.986
|
|
|
11.4 ± 2.4
|
11.2 ± 2.6
|
0.6914
|
|
|
2 (2.1)
|
1 (1.6)
|
0.8221
|
|
|
48 (50.0)
|
31 (49.2)
|
0.922
|
GI, gastrointestinal; NSAIDs, nonsteroidal anti-inflammatory drugs.
The proportions of patients with ischemic heart disease (26 %), who used low-dose
aspirin (31.3 %) and who used warfarin (9.4 %) in the expert group were significantly
higher than those in the nonexpert group (7.9 %, 12.7 %, 1.6 %). However, the other
comorbidities, medications, presence of hemodynamic instability, and hemoglobin levels
were similar between the groups ([Table 1]). Bleeding sources were similar in the two groups ([Table 2]).
Table 2
Endoscopic outcomes, adverse events, and clinical outcomes.
|
Outcomes
|
Expert, (%)
N = 96
|
Nonexert, (%)
N = 63
|
P value
|
|
Endoscopic outcomes
|
|
|
83 (86.5)/10 (10.4)/3 (3.1)
|
58 (92.1)/5 (7.9)/0 (0)
|
0.3086
|
|
|
92 (95.8)
|
62 (98.4)
|
0.362
|
|
|
Not applicable
|
62 (98.4)
|
Not applicable
|
|
|
8.1 ± 5.8
|
11.0 ± 7.2
|
0.0061
|
|
|
32.9 ± 18.9
|
34.5 ± 14.9
|
0.5761
|
|
|
23 (24.0)
|
11 (17.5)
|
0.3284
|
|
Bleeding source by Colonoscopy findings
|
|
|
16 (16.7)
|
10 (15.9)
|
0.8947
|
|
|
41 (42.7)
|
32 (50.8)
|
0.317
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
4 (4.2)
|
1 (1.6)
|
0.362
|
|
|
8 (8.3)
|
6 (9.5)
|
0.7956
|
|
|
0 (0.0)
|
1 (1.6)
|
0.2156
|
|
|
1 (1.0)
|
0 (0.0)
|
0.4164
|
|
|
0 (0.0)
|
2 (3.2)
|
0.0789
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
3 (3.1)
|
0 (0.0)
|
0.1566
|
|
|
11 (11.5)
|
3 (4.8)
|
0.145
|
|
|
16 (16.7)
|
10 (15.9)
|
0.8947
|
|
|
1 (1.0)
|
0 (0.0)
|
0.4164
|
|
Success rate of endoscopic treatment
|
19/20 (95.0)
|
10/10 (100)
|
0.472
|
|
Completion rate of successful endoscopic treatment without expert assist
|
Not applicable
|
63 (100)
|
Not applicable
|
|
Any adverse event
|
|
|
33 (34.4)
|
25 (39.7)
|
0.4965
|
|
|
2 (2.1)
|
5 (7.9)
|
0.1145
|
|
|
1 (1.0)
|
1 (1.6)
|
1.0000
|
|
|
0
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
|
|
1 (1.0)
|
1 (1.6)
|
1.0000
|
|
|
32 (33.3)
|
21 (33.3)
|
1.0000
|
|
|
0
|
0
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1.0000
|
|
|
1 (1.0)
|
0 (0.0)
|
1.0000
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
SeriousaAdverse events
|
|
|
0
|
1 (1.6)
|
0.3962
|
|
|
1 (1.0)
|
0
|
1.0000
|
|
Clinical outcome
|
N
|
|
N
|
|
|
|
|
96
|
36 (37.5)
|
63
|
18 (28.6)
|
0.2449
|
|
|
96
|
1 (1.0)
|
63
|
0 (0.0)
|
0.4164
|
|
|
96
|
0 (0.0)
|
63
|
0 (0.0)
|
Not applicable
|
|
|
95
|
6 (6.3)
|
63
|
3 (4.8)
|
0.6799
|
|
|
96
|
8.0 (6.8)
|
63
|
6.4 (3.9)
|
0.0449
|
|
|
91
|
13 (14.3)
|
56
|
3 (5.4)
|
0.0914
|
|
|
91
|
0 (0.0)
|
56
|
1 (1.8)
|
0.2009
|
|
|
92
|
0 (0.0)
|
56
|
0 (0)
|
Not applicable
|
SRH, stigmata of recent hemorrhage.
1 Data are summarized as the mean (and SD).
Endoscopic outcomes and clinical outcomes
[Table 2] shows endoscopic and clinical outcomes. Rates of adequate bowel preparation were
96.9 % in the expert group and 100 % in the nonexpert group, which were similar and
sufficient. The cecum insertion rate was 95.8 % in the expert group and 98.4 % in
the nonexpert group. The cecum insertion time of the expert group was significantly
shorter than that of the nonexpert group (8.1 ± 5.8 and 11.0 ± 7.2 minutes, P = 0.0061), but no significant difference in total procedure time was observed between
the groups. The completion rate of insertion by nonexperts alone was 98.41 % (62/63).
The identification rate for SRH did not differ between the two groups, and endoscopic
findings of bleeding sources were similar between the groups. The success rate for
endoscopic treatment and the need for additional endoscopic examinations were also
no different between the groups. The completion rate for successful endoscopic treatment
by nonexperts alone was 100 % (63/63). Preparation-related AEs were similar between
the groups and were not severe. With regard to colonoscopy-related AEs, hemorrhagic
shock occurred in one patient (1.0 %) in the expert group and 0 patients in the nonexpert
group. No perforation occurred in either group. Rebleeding within 30 days occurred
in 14.3 % of patients in the expert group and 5.4 % of patients in the nonexpert group
(P = 0.091). No difference was observed in the need for interventional radiology, surgery,
or transfusion between the groups. The mean length of hospital stay was 8.0 days in
the expert group and 6.4 days in the nonexpert group ([Table 2]).
Propensity score-weighted analysis
Details of the baseline characteristics in each group after weighting are shown in
[Table 3]. After weighting, there were no significant differences in cecum insertion rate,
total procedure time, or bleeding sources between the two groups. There were no significant
differences in SRH identification, successful endoscopic treatment rate, transfusion
rate, length of stay, thrombotic events, 30-day rebleeding rate, or 30-day mortality
rate between the two groups. AEs did not differ between the groups ([Table 4]). These findings remained unchanged in the propensity score-weighted analysis.
Table 3
Patient characteristics after propensity score weighting.
|
Characteristics
|
Expert, %
|
Nonexpert, %
|
P value
|
Standarized difference
|
|
Age, mean ± SD
|
67.5 ± 10.0
|
67.6 ± 10.1
|
0.966
|
0.011969
|
|
Sex, male (%)
|
67.6
|
67.3
|
0.971
|
0.04153
|
|
Body mass index, mean ± SD
|
23.4 ± 2.3
|
23.5 ± 2.2
|
0.807
|
0.044433
|
|
Comorbidities
|
|
|
32.0
|
33.2
|
0.896
|
0.20694
|
|
|
0.7 ± 0.7
|
0.7 ± 0.9
|
0.9
|
0
|
|
|
6.8
|
7.1
|
0.943
|
0.11416
|
|
|
51
|
51
|
0.999
|
0
|
|
|
3.6
|
4.4
|
0.825
|
0.41008
|
|
|
0
|
0
|
0.812
|
0
|
|
|
12.4
|
12.0
|
0.954
|
0.10899
|
|
|
0
|
0
|
0.549
|
Not applicable
|
|
|
12.3
|
11.9
|
0.943
|
0.12952
|
|
|
0
|
0
|
|
Not applicable
|
|
|
5.0
|
4.7
|
0.935
|
0.1495
|
|
|
6.3
|
7.6
|
0.778
|
0.49294
|
|
|
0
|
0
|
|
Not applicable
|
|
|
0
|
0
|
|
Not applicable
|
|
|
8.1
|
8.0
|
0.993
|
0.01764
|
|
|
0
|
0
|
|
Not applicable
|
|
|
0
|
0
|
|
Not applicable
|
|
Medication
|
|
|
14.0
|
14.1
|
0.983
|
0.03736
|
|
|
5.2
|
4.7
|
0.906
|
0.22894
|
|
|
3.6
|
3.0
|
0.851
|
0.36283
|
|
|
3.4
|
3.1
|
0.94
|
0.1275
|
|
|
2.5
|
2.4
|
0.969
|
0.06442
|
|
|
4.4
|
3.8
|
0.875
|
0.28242
|
|
|
17.2
|
18.5
|
0.858
|
0.31727
|
|
Initial assessment
|
|
|
5.6
|
4.4
|
0.783
|
0.54683
|
|
|
11.9 ± 1.5
|
11.8 ± 1.9
|
0.909
|
0.058421
|
|
|
0
|
0
|
0.712
|
0
|
|
|
41.9
|
44.7
|
0.776
|
0.41894
|
Parenthesis shows %.
NSAIDs, nonsteroidal anti-inflammatory drugs.
Table 4
Endoscopic outcomes, adverse events, and clinical outcomes after propensity score
weighting.
|
Outcomes
|
Expert, %
|
Nonexpert, %
|
P value
|
|
Endoscopic outcomes
|
|
|
95.36
|
97.64
|
0.559
|
|
|
7.6 ± 3.6
|
10.6 ± 5.8
|
0.018
|
|
|
34.9 ± 12.7
|
34.7 ± 11.9
|
0.949
|
|
|
24.05
|
17.57
|
0.4163
|
|
Bleeding source by Colonoscopy findings
|
|
|
15.51
|
15.22
|
0.967
|
|
|
43.35
|
48.34
|
0.609
|
|
|
0
|
0
|
Not applicable
|
|
|
4.43
|
0.87
|
0.17
|
|
|
10.99
|
10.97
|
0.997
|
|
|
0
|
2.19
|
Not applicable
|
|
|
1.02
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
|
|
4.91
|
0
|
Not applicable
|
|
|
5.1
|
4.55
|
0.891
|
|
|
17.84
|
20.05
|
0.779
|
|
|
0
|
0
|
Not applicable
|
|
The success rate of endoscopic treatment
|
97.14
|
100
|
0.3263
|
|
Completion rate of successful endoscopic treatment without expert assist
|
Not applicable
|
63 (100)
|
Not applicable
|
|
Adverse event
|
|
|
|
|
|
37.4
|
37.3
|
0.9885
|
|
|
3.1
|
8.5
|
0.2747
|
|
|
0.7
|
2.4
|
0.3838
|
|
|
0
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
|
|
0.1
|
1.9
|
0.0704
|
|
|
36.7
|
28.4
|
0.3594
|
|
|
0
|
0
|
Not applicable
|
|
|
0.5
|
0
|
Not applicable
|
|
|
0.5
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
|
Serious adverse events
|
|
|
0
|
2.1
|
Not applicable
|
|
|
0.5
|
0
|
Not applicable
|
|
Outcome
|
|
|
33.7
|
26.6
|
0.4193
|
|
|
1.4
|
0
|
0.3146
|
|
|
0
|
0
|
Not applicable
|
|
|
6.6
|
6.1
|
0.908
|
|
|
7.0
|
6.1
|
0.1943
|
|
|
15.7
|
5.39
|
0.0792
|
|
|
0
|
2.31
|
0.3118
|
SRH, stigmata of recent hemorrhage.
1 Summarized by mean (and SD).
Subgroup analysis according to years of endoscopic experience
Similarly, we compared endoscopic and clinical outcomes between the group with < 3
years of endoscopic experience (N = 8, [Table 5]) and the expert group and between the group with 3 to 6 years of endoscopic experience
(N = 32, [Table 6]) and the expert group. The SRH identification rate was higher in the expert group
than in both nonexpert groups; however, the differences were not significant. Endoscopic
findings of the bleeding sources were similar between the expert group and both nonexpert
groups. Colonoscopy-related AEs also were similar. Rebleeding within 30 days occurred
more often in patients in the expert group than in either nonexpert group, and the
length of stay was significantly longer in the expert group than in the nonexpert
group with < 3 years of experience ([Table 5], [Table 6]).
Table 5
Endoscopic outcomes, adverse events, and clinical outcomes between expert group and
groups with < 3-year endoscopic experience.
|
Outcomes
|
Expert, (%)
N = 96
|
< 3 years, (%)
N = 8
|
P value
|
|
Endoscopic outcomes
|
|
|
92 (95.8)
|
8 (100)
|
1
|
|
|
8.1 ± 5.8
|
6.8 ± 1.9
|
0.9949
|
|
|
32.9 ± 18.9
|
34.3 ± 9.1
|
0.3861
|
|
|
23 (24.0)
|
1 (12.5)
|
0.3585
|
|
Bleeding source by colonoscopy findings
|
|
|
16 (16.7)
|
1 (12.5)
|
1
|
|
|
41 (42.7)
|
3 (37.5)
|
1
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
4 (4.2)
|
0 (0.0)
|
1
|
|
|
8 (8.3)
|
2 (25.0)
|
0.1704
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
3 (3.1)
|
0 (0.0)
|
1
|
|
|
11 (11.5)
|
0 (0.0)
|
1
|
|
|
16 (16.7)
|
2 (25.0)
|
0.6245
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
Success rate of endoscopic treatment
|
19/20 (95.0)
|
1/1 (100)
|
0.3049
|
|
Completion rate of successful endoscopic treatment without expert assist
|
Not applicable
|
8 (100)
|
Not applicable
|
|
Adverse event
|
|
|
33 (34.4)
|
3(37.50)
|
1
|
|
|
2 (2.1)
|
1(12.50)
|
1
|
|
|
1 (1.0)
|
0 (0.0)
|
0.2154
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
Exacerbation bleeding
|
32 (33.3)
|
2 (25.0)
|
1
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
Serious adverse events
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
|
1
|
|
Outcome
|
|
|
23 (24.0)
|
1 (12.5)
|
0.0489
|
|
|
1 (1.0)
|
0
|
0.3148
|
|
|
0
|
0
|
Not applicable
|
|
|
6 (6.3)
|
1 (12.5)
|
0.605
|
|
|
6.8
|
5.5
|
0.0346
|
|
|
13 (14.3)
|
0
|
< 0.001
|
|
|
0
|
0
|
Not applicable
|
|
|
0
|
0
|
Not applicable
|
SRH, stigmata of recent hemorrhage.
1 Summarized by mean (and SD).
Table 6
Endoscopic outcomes, adverse, events and clinical outcomes in expert group and group
with 3 to 6 years of endoscopic experience
|
Outcomes
|
Expert, (%)
N = 96
|
3–6 years, (%)
N = 32
|
P value
|
|
Endoscopic outcomes
|
|
|
92 (95.8)
|
31 (96.9)
|
1
|
|
|
8.1±5.8
|
12.5±8.7
|
0.0012
|
|
|
32.9±18.9
|
33.5±16.0
|
0.8107
|
|
|
23 (24.0)
|
5 (15.6)
|
0.2827
|
|
Bleeding source by colonoscopy findings
|
|
|
16 (16.7)
|
5 (15.6)
|
0.8904
|
|
|
41 (42.7)
|
18 (56.3)
|
0.1832
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
4 (4.2)
|
1 (3.1)
|
1
|
|
|
8 (8.3)
|
1 (3.1)
|
0.4487
|
|
|
0 (0.0)
|
1 (3.1)
|
0.25
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
0 (0.0)
|
2 (6.3)
|
0.061
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
|
3 (3.1)
|
0 (0.0)
|
0.5726
|
|
|
11 (11.5)
|
3 (9.4)
|
1
|
|
|
16 (16.7)
|
3 (9.4)
|
0.3997
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
Success rate of endoscopic treatment
|
19/20 (95.0)
|
5/5 (100)
|
0.3049
|
|
Completion rate of successful endoscopic treatment without expert assist
|
Not applicable
|
32 (100)
|
Not applicable
|
|
Adverse event
|
|
|
33 (34.4)
|
3(37.50)
|
1
|
|
|
2 (2.1)
|
1(12.50)
|
1
|
|
|
1 (1.0)
|
0 (0.0)
|
0.2154
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
32 (33.3)
|
2 (25.0)
|
1
|
|
|
0
|
0 (0.0)
|
Not applicable
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
|
0 (0.0)
|
0 (0.0)
|
Not applicable
|
|
Serious adverse events
|
|
|
0
|
1 (3.1)
|
0.25
|
|
|
1 (1.0)
|
0 (0.0)
|
1
|
|
Outcome
|
|
|
36 (37.5)
|
9 (28.1)
|
0.3165
|
|
|
1 (1.0)
|
0
|
0.3148
|
|
|
0
|
0
|
Not applicable
|
|
|
6 (6.3)
|
0
|
0.0114
|
|
|
6.8
|
6.6
|
0.1593
|
|
|
13 (14.3)
|
1 (3.1)
|
0.0197
|
|
|
0
|
1 (3.1)
|
0.3096
|
|
|
0
|
0
|
Not applicable
|
SRH, stigmata of recent hemorrhage.
1 Summarized by mean (and SD).
Discussion
Contrary to our hypothesis, we found that the rate of SRH identification, rate of
successful endoscopic hemostasis, 30-day rebleeding rate, and AEs did not differ between
the expert and nonexpert groups. In addition, we performed a subgroup analysis according
to the number of years of endoscopy experience among nonexperts; however, nonexperts
performed as well as experts regardless of their years of experience.
A possible explanation is that it is difficult for even experts to achieve a higher
rate of SRH identification in cases of diverticular bleeding [6], which accounts for approximately 30 % to 50 % of cases of ALGIB [7]
[8]
[9], as these cases involve intermittent bleeding or spontaneous cessation of bleeding
[6]
[10]. Another explanation is that the completion rate of insertion by nonexperts alone
was as high as 98.4 %, suggesting that the nonexpert group may be quite experienced.
In the present study, the length of hospital stay was significantly longer in the
expert group than in the nonexpert group. In addition, the 30-day rebleeding rate
in the expert group was not significantly higher than that in the nonexpert group. We
believe this is because the expert group had higher proportions of patients with ischemic
heart diseases, chronic heart failure, or cerebral vascular diseases. Therefore, there
were more patients taking antithrombotic drugs in the expert group than in the nonexpert
group, which resulted in a higher rebleeding rate in the former group. Consequently,
there was a bias in selection of patients undergoing colonoscopies performed by experts.
To adjust for this bias, we conducted a propensity score-weighted analysis. After
propensity score weighting, we found that the insertion time of the nonexperts was
longer by 3 minutes than that of the experts. However, there were no significant differences
in the SRH identification rate and bleeding source as primary outcomes between the
two groups. Performance of the colonoscopy by a nonexpert can lead to a significant
prolongation of the cecum insertion time by 3 minutes, but the total procedure time
and the rate of successful endoscopic treatment were similar between the two groups.
Therefore, this prolongation of insertion time may not affect the primary outcomes,
including diagnosis and endoscopic treatment. Furthermore, the performance of endoscopic
therapies, such as clipping, bipolar coagulation, and band ligation, was also similar
between the two groups (data not shown). Therefore, these factors may have contributed
to the lack of differences in the clinical outcomes, including the 30-day rebleeding
rate and AE rate, between the groups.
Training operators to perform endoscopic procedures, including diagnostic and therapeutic
procedures, is a key objective of endoscopy fellowships. To gain competency, trainees
generally learn endoscopic procedures through hands-on experience under the supervision
of experts [11]. Regarding training programs to increase the adenoma detection rate (ADR) and to
decrease the incidence of overlooking interval colorectal cancer, routine monitoring
colonoscopy quality metrics can be useful to improve the effectiveness of screening
colonoscopies [12]. However, improving the identification of SRH is still challenging even for experts
because SRH is rare, and it is even more difficult after successful endoscopic hemostasis
[13]. By contrast, a greater degree of safety in the nonexpert group was shown in our
study. Therefore, we believe that the endoscopic procedure performed by nonexperts
for ALGIB is acceptable and can be included in the training program.
Our study has several strengths. First, our multicenter RCT is the first to evaluate
the feasibility of the performance of colonoscopies by nonexpert endoscopists for
patients with ALGIB. Second, we performed further investigations to explore the data
in more depth. Nevertheless, there are several limitations of the study. First, patients
were not randomly allocated to the expert and nonexpert groups. Second, there were
no standardized criteria used to select the nonexpert endoscopists who performed colonoscopies
in the participating hospitals. We also should consider the potential for selection
bias, as the expert group performed much more challenging procedures. Third, there
are no standardized teaching and training programs among the participating hospitals.
Fourth, we could not collect data on what kind of technical advice the non-expert
endoscopists received, including the selection of the appropriate endoscopy hemostasis
device. This advice may have been helpful for successful hemostasis in the non-expert
group. Finally, subgroup analysis according to the years of endoscopic experience
included a small population and did not reach adequate statistical power.
Conclusions
In summary, we found that the performance of colonoscopies for ALGIB by nonexpert
endoscopists did not yield worse clinical outcomes or reduced safety, suggesting that
colonoscopy for ALGIB may be a feasible advanced procedure for nonexpert endoscopists
to perform.
Tsutomu Nishida, Ryota Niikura, Naoyoshi Nagata et al. Feasibility and safety of colonoscopy
performed by nonexperts for acute lower gastrointestinal bleeding: post hoc analysis Endoscopy International Open 2021; 09: E943–E954. DOI: 10.1055/a-1464-0809
In the above mentioned article an author name was corrected. Correct is: Ryota Niikura.
