Initial management for acute lower gastrointestinal bleeding

Table 1 Risk factors and odds ratios for various outcomes according to 11 studies[7,8,20-28]

	Severe/recurrent bleeding	In-hospital complications3	Adverse outcomes4	Mortality
Patient characteristic
Older age	2.31	-	4.21	4.92
Male sex	6	-	-	1.5-1.6
Lower body mass index	-	-	-	2.0
Smoking	-	-	0.5	-
Comorbidities
Charlson index > 2 or ≥ 2	1.7-1.9	-	-	3.0
Unstable comorbid diseases	-	2.9	-	-
Congestive heart failure	-	-	-	1.5
Cardiovascular disease	6	-	-	-
Dementia	6	-	-	5.2
Metastatic cancer	-	-	-	5.0
Chronic kidney disease	-	-	-	1.8-2.2
Liver disease	-	-	-	1.9
Chronic pulmonary disease	-	-	-	1.6
History of colonic diverticulosis and/or angiodysplasia	6	-	-	6
Presenting symptom
Syncope / altered mental status	2.5-3.3	2.0	-	6
No diarrhea	2.2	-	-	-
No abdominal tenderness	2.4-3.0	-	-	-
Ongoing bleeding	-	3.1	-	-
Bleeding in the first 4 h	2.3	-	-	-
Medication
NSAIDs (non-aspirin)1	2.5	-	-	1.5
Aspirin	1.9-2.1	-	-	-
Antiplatelet drugs (non-aspirin)	2.0	-	-	-
Anticoagulants	-	-	-	1.5
Physical examination
Blood pressure ≤ 100 or ≤ 115 mmHg	2.3-3.5	3.0	-	6
Heart rate ≥ 100/min	3.7	-	-	-
Abnormal vital signs after 1 h	4.3	-	-	-
Abnormal hemodynamic parameters	-	-	2.1	-
Gross blood on rectal examination	3.5-3.9	-	-	6
Laboratory data
Hemoglobin < 10 g/dL	3.6	-	-	-
Albumin < 3.0 or < 3.8 g/dL	2.0-2.9	-	-	2.9
Creatinine > 150 or > 133 µmol/L	6	-	10.3	6
Hematocrit < 35% or < 30%	4.7-6.3	-	-	6
Prothrombin time > 1.2 times control	-	2.0	-	-
Clinical course
Rebleeding	-	-	1.9	-
Intestinal ischemia	-	-	-	3.5
Coagulation defects	-	-	-	2.3
Hypovolemia	-	-	-	2.2
Blood transfusion	-	-	-	1.6-2.8
Need for intervention5	-	-	-	2.3-2.4
In-hospital onset LGIB	-	-	-	2.4

¹Age > 60 years;

²Age > 70 years;

³Either surgery, intensive care unit admission, or mortality;

⁴Either rebleeding, surgery, or mortality;

⁵Interventional radiology or surgery;

⁶The variables were identified as risk factors, but odds ratios of these were not described. NSAIDs: Non-steroidal anti-inflammatory drugs.

Table 2 Risk scoring systems for severe acute lower gastrointestinal bleeding which have been validated

Derivation study	Outcomes	Risk factors	ROC-AUC	Validation study
Strate et al[21]	Severe bleeding	Syncope	0.76	Prospective cohort (n = 275)
(n = 252)	(continuous and/or recurrent bleeding)	No abdominal tenderness		ROC-AUC: 0.75
		Aspirin use
		Heart rate ≥ 100/min
		Systolic blood pressure ≤ 115 mmHg
		Bleeding per rectum in the first 4 h
		Charlson comorbidity index > 2
Das et al[22]	Rebleeding	(19 factors)	0.92	Prospective cohort (n = 142)
(n = 120)	Need for intervention	Age	0.93
Artificial neural network based model	In-hospital mortality	Comorbidity (5 factors)	0.95
		History (4 factors)
		Features at presentation (2 factors)
		Features at initial assessment (2 factors)
		Initial laboratory data (5 factors)
Aoki et al[24]	Severe bleeding	(NOBLADS)	0.77	Prospective cohort (n = 161)
(n = 439)	(Continuous and/or recurrent bleeding)	NSAIDs use		ROC-AUC: 0.76
		No diarrhea		Retrospective cohort (n = 511)
		No abdominal tenderness		ROC-AUC: 0.74
		Blood pressure (systolic) ≤ 100 mmHg
		Albumin level < 3.0 g/dL
		Antiplatelet drugs use (non-aspirin)
		Disease score ≥ 21
		Syncope
Oakland et al[27]	Safe discharge	Age	0.84	Prospective cohort (n = 288)
(n = 2336)	(Absence of death, rebleeding, intervention, blood transfusion,	Male sex		ROC-AUC: 0.79
	or 28 d readmission)	Blood on rectal examination
		Heart rate
		Systolic blood pressure
		Hemoglobin level
		Previous LGIB admission
Sengupta et al[28]	30 d mortality	Age	0.81	Retrospective cohort (n = 2060)
(n = 4044)		Dementia		ROC-AUC: 0.72
		Metastatic cancer
		Chronic kidney disease
		Chronic pulmonary disease
		Anticoagulant use
		Hematocrit level
		Albumin level

¹Charlson comorbidity index. LGIB: Lower gastrointestinal bleeding; ROC-AUC: The area under the receiver operating characteristics curve.

Table 3 Utility of early colonoscopy compared with elective colonoscopy according to randomized controlled trials and meta-analyses

Study	Study design	Sample size	Bleeding source localization	Endoscopic intervention	Surgery required	Rebleeding	Length of stay	Adverse events	Mortality
Green et al[41]	RCT1	100	2.6 (1.1-6.2)4	-	NS	NS	NS	NS	NS
Laine et al[42]	RCT2	72	NS	-	-	NS	NS	-	-
Sengupta et al[44]	Meta-analysis3	901	2.97 (2.11-4.19)4	3.99 (2.59-6.13)4	NS	NS	-	-	NS
Kouanda et al[43]	Meta-analysis3	24,396	NS	1.70 (1.08-2.67)4	-	NS	-	NS	NS
Seth et al[45]	Meta-analysis3	23,419	SRH detection 2.85 (1.90-4.28)4	NS	NS	NS	NS	-	NS

¹Primary end point was rebleeding;

²Primary end point was further bleeding (continuous bleeding and/or rebleeding);

³Meta-analyses included 2 randomized controlled trials;

⁴Odds ratio (95% confidential interval). RCT: Randomized controlled trial; NS: Not significantly; SRH: Stigmata of recent hemorrhage.

Table 4 Clinical significance of performing contrast-enhanced computed tomography before colonoscopy for colonic diverticular bleeding

Study	Study design	Sample size1	Detection rate of extravasation on CT (%)	SRH detection rate on CS after extravasation on CT (%)	SRH detection rate on CS after no extravasation on CT (%)	Predictors for extravasation on CT
Obana et al[57]	Prospective	52	15	50	36	History of diverticular bleeding
						Within 2 h of last hematochezia
Nakatsu et al[54]	Retrospective	346	30	68	20	-
Nagata et al[53]	Retrospective	77	31	63	38	History of diverticular bleeding
Sugiyama et al[55]	Retrospective	55	36	60	31	-
Wada et al[118]	Retrospective	100	23	70	-	-
Umezawa et al[56]	Prospective	202	25	76	18	Within 4 h of last hematochezia

¹Patients with colonic diverticular bleeding who underwent contrast-enhanced computed tomography before colonoscopy. LGIB: Lower gastrointestinal bleeding; CE-CT: Contrast-enhanced computed tomography; SRH: Stigmata of recent hemorrhage; CS: Colonoscopy; UGIB: Upper gastrointestinal bleeding; PPI: Proton pomp inhibitor; DOAC: Direct-acting oral anticoagulant; BUN: Blood urea nitrogen; Cr: Creatinine; NSAID: Nonsteroidal anti-inflammatory drug; Hb: Hemoglobin; PT-INR: Prothrombin time-international normalized ratio; ROC-AUC: The area under the receiver operating characteristics curve; RR: Relative risk; CI: Confidence interval; GIB: Gastrointestinal bleeding; RCT: Randomized controlled trial; OR: Odds ratio; HR: Hazard ratio.