Gastroenterol Res

Gastroenterology Research, ISSN 1918-2805 print, 1918-2813 online, Open Access

Article copyright, the authors; Journal compilation copyright, Gastroenterol Res and Elmer Press Inc

Journal website https://www.gastrores.org

Original Article

Volume 15, Number 4, August 2022, pages 162-172

Early Colonoscopy in Hospitalized Patients With Acute Lower Gastrointestinal Bleeding: A Nationwide Analysis

Figure 1. Receiver operating curve (ROC) comparing the predicted values of mortality obtained after the binary regression when compared with the observed values for the cases in the study.

**Table 1.** Frequency of LGIB Etiologies Based on Presence of ICD-10 Codes, in the Total Population, and in Cases That Received a Colonoscopy (N = 1,549,605)^a
Diagnosis	Frequency (%^b)	Frequency for colonoscopy patients (%^b)
^aAll numbers are weighted by NIS weight. ^bThe sum of all % values may add up to > 100 as some patients may have multiple diagnoses listed in their problem list. LGIB: lower gastrointestinal bleed; NIS: National (Nationwide) Inpatient Sample; ICD-10: International Classification of Disease 10th Edition.
Anorectal bleed	119,330 (7.7%)	23,940 (8.4%)
Diverticulosis	271,095 (17.5%)	122,720 (43.0%)
Diverticulitis	44,430 (2.9%)	7,835 (2.7%)
Angiodysplasia	90,420 (5.8%)	12,920 (4.5%)
Dieulafoy lesion	5,585 (0.4%)	1,190 (0.4%)
Melena	896,325 (57.8%)	112,870 (39.6%)
LGIB (primary diagnosis) with polyps, or benign neoplasm of large intestine (as secondary diagnosis)	49,070 (3.2%)	7,695 (2.7%)
LGIB (primary diagnosis) with malignant neoplasm of large intestine (as secondary diagnosis)	5,190 (0.3%)	635 (0.2%)
LGIB (primary diagnosis) with malignant neoplasm of anus (as secondary diagnosis)	135 (0%)	10 (0%)
LGIB (primary diagnosis) with malignant neoplasm of small intestine (as secondary diagnosis)	295 (0%)	15 (0%)
LGIB (primary diagnosis) with ischemia of intestine (as secondary diagnosis)	10,965 (0.7%)	2,365 (0.8%)
LGIB (primary diagnosis) with noninfectious colitis (as secondary diagnosis)	11,705 (0.8%)	1,535 (0.5%)
LGIB (primary diagnosis) with infectious colitis (as secondary diagnosis)	1,305 (0.1%)	75 (0%)
LGIB (primary diagnosis) with Crohn’s disease (as secondary diagnosis)	13,560 (0.9%)	1,065 (0.4%)
LGIB (primary diagnosis) with ulcerative colitis (as secondary diagnosis)	48,515 (3.1%)	2,410 (0.8%)
LGIB (primary diagnosis) with large intestinal fistula (as secondary diagnosis)	1,015 (0.1%)	350 (0.1%)
LGIB (primary diagnosis) with anal fissure (as secondary diagnosis)	75 (0%)	15 (0%)
Patients that received a colonoscopy	285,165 (18.4%)
Patients that received an early colonoscopy	107,055 (6.9%)

Table 1. Frequency of LGIB Etiologies Based on Presence of ICD-10 Codes, in the Total Population, and in Cases That Received a Colonoscopy (N = 1,549,605)^a

Diagnosis

Frequency (%^b)

Frequency for colonoscopy patients (%^b)

^aAll numbers are weighted by NIS weight. ^bThe sum of all % values may add up to > 100 as some patients may have multiple diagnoses listed in their problem list. LGIB: lower gastrointestinal bleed; NIS: National (Nationwide) Inpatient Sample; ICD-10: International Classification of Disease 10th Edition.

Anorectal bleed

119,330 (7.7%)

23,940 (8.4%)

Diverticulosis

271,095 (17.5%)

122,720 (43.0%)

Diverticulitis

44,430 (2.9%)

7,835 (2.7%)

Angiodysplasia

90,420 (5.8%)

12,920 (4.5%)

Dieulafoy lesion

5,585 (0.4%)

1,190 (0.4%)

Melena

896,325 (57.8%)

112,870 (39.6%)

LGIB (primary diagnosis) with polyps, or benign neoplasm of large intestine (as secondary diagnosis)

49,070 (3.2%)

7,695 (2.7%)

LGIB (primary diagnosis) with malignant neoplasm of large intestine (as secondary diagnosis)

5,190 (0.3%)

635 (0.2%)

LGIB (primary diagnosis) with malignant neoplasm of anus (as secondary diagnosis)

135 (0%)

10 (0%)

LGIB (primary diagnosis) with malignant neoplasm of small intestine (as secondary diagnosis)

295 (0%)

15 (0%)

LGIB (primary diagnosis) with ischemia of intestine (as secondary diagnosis)

10,965 (0.7%)

2,365 (0.8%)

LGIB (primary diagnosis) with noninfectious colitis (as secondary diagnosis)

11,705 (0.8%)

1,535 (0.5%)

LGIB (primary diagnosis) with infectious colitis (as secondary diagnosis)

1,305 (0.1%)

75 (0%)

LGIB (primary diagnosis) with Crohn’s disease (as secondary diagnosis)

13,560 (0.9%)

1,065 (0.4%)

LGIB (primary diagnosis) with ulcerative colitis (as secondary diagnosis)

48,515 (3.1%)

2,410 (0.8%)

LGIB (primary diagnosis) with large intestinal fistula (as secondary diagnosis)

1,015 (0.1%)

350 (0.1%)

LGIB (primary diagnosis) with anal fissure (as secondary diagnosis)

75 (0%)

15 (0%)

Patients that received a colonoscopy

285,165 (18.4%)

Patients that received an early colonoscopy

107,055 (6.9%)

**Table 2.** Demographic Differences in Patients That Received Early Versus Delayed Colonoscopy^a (N = 285,165)
Characteristic	Early colonoscopy	Delayed colonoscopy	P value/total number
^aNumbers weighted by NIS weight. The total numbers in each category may not necessarily add up to n = 285,165 as some of the values may not have been reported in the database, leading to those cases being excluded from these calculations. ^bMedian values would be a more accurate measure of central tendency as compared to mean for this data. NIS: National (Nationwide) Inpatient Sample; CCI: Charlson Comorbidity Index; SD: standard deviation.
Age, median^b	73	73	< 0.001
Age, mean (SD)	70.90 (14.45)	70.59 (14.39)	< 0.001
Age group, (in years)			< 0.001
18 - 35 (% within age group)	2,790 (37.9%)	4,580 (62.1%)	7,370 (100%)
36 - 50	7,650 (37.7%)	12,625 (62.3%)	20,275
51 - 65	21,815 (36.4%)	38,130 (63.6%)	59,945
> 66	74,800 (37.9%)	122,775 (62.1%)	197,575
Gender			< 0.001
Male (% within gender group)	56,835 (39.3%)	87,735 (60.7%)	144,570 (100%)
Female	50,190 (35.7%)	90,350 (64.3%)	140,540
Race			< 0.001
White (% within race group)	68,995 (38.1%)	112,245 (61.9%)	181,240 (100%)
Black	19,610 (35%)	36,475 (65%)	24,725
Hispanic	9,245 (37.4%)	15,480 (62.6%)	24,725
Asian/Pacific Islander	3,130 (43.4%)	4,075 (56.6%)	7,205
Native American	560 (35.2%)	1,030 (64.8%)	1,590
Other	2,300 (37.9%)	3,765 (62.1%)	6,065
Type of insurance			< 0.001
Medicare (% within group)	75,360 (37.2%)	127,485 (62.8%)	202,845 (100%)
Medicaid	6,850 (31.8%)	14,710 (68.2%)	21,560
Private	19,845 (42%)	27,450 (58%)	47,295
Self-pay	2,545 (36.1%)	4,510 (63.9%)	7.055
No charge	270 (36.7%)	465 (63.3%)	735
Other	2,070 (38.7%)	3,280 (61.3%)	5,350
Charlson Comorbidity Index grouping			< 0.001
0 (% within group)	4,740 (43%)	6,280 (57%)	11,020 (100%)
1	5,565 (41.9%)	7,705 (58.1%)	13,270
2	9,170 (44.1%)	11,640 (55.9%)	20,810
≥ 3	87,580 (36.5%)	152,485 (63.5%)	240,065
CCI, median^b	5	5	< 0.001
CCI, mean (SD)	4.62 (2.37)	5.12 (2.48)	< 0.001
Hospital location/teaching status			< 0.001
Rural (% within group)	2,090 (39.7%)	3,180 (60.3%)	5,270 (100%)
Urban nonteaching	7,350 (40.9%)	10,600 (59.1%)	17,950
Urban teaching	17,155 (37.6%)	28,500 (62.4%)	45,655
Admission day of the week			< 0.001
Weekday admission (% within group)	84,940 (39.5%)	130,165 (60.5%)	215,105 (100%)
Weekend admission	22,115 (31.6%)	47,945 (68.4%)	70,060

Table 2. Demographic Differences in Patients That Received Early Versus Delayed Colonoscopy^a (N = 285,165)

Characteristic

Early colonoscopy

Delayed colonoscopy

P value/total number

^aNumbers weighted by NIS weight. The total numbers in each category may not necessarily add up to n = 285,165 as some of the values may not have been reported in the database, leading to those cases being excluded from these calculations. ^bMedian values would be a more accurate measure of central tendency as compared to mean for this data. NIS: National (Nationwide) Inpatient Sample; CCI: Charlson Comorbidity Index; SD: standard deviation.

Age, median^b

< 0.001

Age, mean (SD)

70.90 (14.45)

70.59 (14.39)

< 0.001

Age group, (in years)

< 0.001

18 - 35 (% within age group)

2,790 (37.9%)

4,580 (62.1%)

7,370 (100%)

36 - 50

7,650 (37.7%)

12,625 (62.3%)

20,275

51 - 65

21,815 (36.4%)

38,130 (63.6%)

59,945

> 66

74,800 (37.9%)

122,775 (62.1%)

197,575

Gender

< 0.001

Male (% within gender group)

56,835 (39.3%)

87,735 (60.7%)

144,570 (100%)

Female

50,190 (35.7%)

90,350 (64.3%)

140,540

Race

< 0.001

White (% within race group)

68,995 (38.1%)

112,245 (61.9%)

181,240 (100%)

Black

19,610 (35%)

36,475 (65%)

24,725

Hispanic

9,245 (37.4%)

15,480 (62.6%)

24,725

Asian/Pacific Islander

3,130 (43.4%)

4,075 (56.6%)

7,205

Native American

560 (35.2%)

1,030 (64.8%)

1,590

Other

2,300 (37.9%)

3,765 (62.1%)

6,065

Type of insurance

< 0.001

Medicare (% within group)

75,360 (37.2%)

127,485 (62.8%)

202,845 (100%)

Medicaid

6,850 (31.8%)

14,710 (68.2%)

21,560

Private

19,845 (42%)

27,450 (58%)

47,295

Self-pay

2,545 (36.1%)

4,510 (63.9%)

7.055

No charge

270 (36.7%)

465 (63.3%)

735

Other

2,070 (38.7%)

3,280 (61.3%)

5,350

Charlson Comorbidity Index grouping

< 0.001

0 (% within group)

4,740 (43%)

6,280 (57%)

11,020 (100%)

5,565 (41.9%)

7,705 (58.1%)

13,270

9,170 (44.1%)

11,640 (55.9%)

20,810

≥ 3

87,580 (36.5%)

152,485 (63.5%)

240,065

CCI, median^b

< 0.001

CCI, mean (SD)

4.62 (2.37)

5.12 (2.48)

< 0.001

Hospital location/teaching status

< 0.001

Rural (% within group)

2,090 (39.7%)

3,180 (60.3%)

5,270 (100%)

Urban nonteaching

7,350 (40.9%)

10,600 (59.1%)

17,950

Urban teaching

17,155 (37.6%)

28,500 (62.4%)

45,655

Admission day of the week

< 0.001

Weekday admission (% within group)

84,940 (39.5%)

130,165 (60.5%)

215,105 (100%)

Weekend admission

22,115 (31.6%)

47,945 (68.4%)

70,060

**Table 3.** Adverse Events and Intervention Data Reported in Patients With Lower Gastrointestinal Bleeding That Received Early Versus Delayed Colonoscopy (N = 285,150)
Event/intervention	Early colonoscopy (n = 107,045)	Delayed colonoscopy (n = 178,105)	P value
^aAlthough we reported the mean values, the median value would be a more accurate measurement of central tendency for this data set. LOS: length of stay; TOTCHG: total charges of hospitalization; SD: standard deviation.
Transfusion of any blood products	34,535 (32.3%)	66,185 (37.2%)	< 0.001
Transfusion of red cell related products only	33,645 (31.4%)	64,905 (36.4%)	< 0.001
Hypovolemia or shock	7,660 (7.2%)	11,990 (6.7%)	< 0.001
Acute kidney injury	15,925 (14.9%)	41,140 (23.1%)	< 0.001
Dialysis	1,525 (1.4%)	4,330 (2.4%)	< 0.001
Acute respiratory failure	1,420 (1.3%)	3,835 (2.2%)	< 0.001
Ventilator support (h)			< 0.001
< 24 h	480 (0.4%)	970 (0.5%)
24 - 96 h	825 (0.8%)	1,995 (1.1%)
> 96 h	510 (0.5%)	2,485 (1.4%)
Endoscopic destruction of large intestine lesions	620 (0.6%)	1,040 (0.6%)	0.871
Outcomes
Death (% within colonoscopy group)	1,005 (0.9%)	2,530 (1.4%)	< 0.001
Median length of stay (LOS)	3 days	5 days	< 0.001
Median total charges (TOTCHG)	$32,037	$44,092	< 0.001
Mean^a LOS (Standard deviation)	3.99 days (4.64)	7.10 days (8.40)	< 0.001
Mean^a TOTCHG (SD)	$49,722 (71,486)	$77,048 (133,027)	< 0.001

Table 3. Adverse Events and Intervention Data Reported in Patients With Lower Gastrointestinal Bleeding That Received Early Versus Delayed Colonoscopy (N = 285,150)

Event/intervention

Early colonoscopy (n = 107,045)

Delayed colonoscopy (n = 178,105)

P value

^aAlthough we reported the mean values, the median value would be a more accurate measurement of central tendency for this data set. LOS: length of stay; TOTCHG: total charges of hospitalization; SD: standard deviation.

Transfusion of any blood products

34,535 (32.3%)

66,185 (37.2%)

< 0.001

Transfusion of red cell related products only

33,645 (31.4%)

64,905 (36.4%)

< 0.001

Hypovolemia or shock

7,660 (7.2%)

11,990 (6.7%)

< 0.001

Acute kidney injury

15,925 (14.9%)

41,140 (23.1%)

< 0.001

Dialysis

1,525 (1.4%)

4,330 (2.4%)

< 0.001

Acute respiratory failure

1,420 (1.3%)

3,835 (2.2%)

< 0.001

Ventilator support (h)

< 0.001

< 24 h

480 (0.4%)

970 (0.5%)

24 - 96 h

825 (0.8%)

1,995 (1.1%)

> 96 h

510 (0.5%)

2,485 (1.4%)

Endoscopic destruction of large intestine lesions

620 (0.6%)

1,040 (0.6%)

0.871

Outcomes

Death (% within colonoscopy group)

1,005 (0.9%)

2,530 (1.4%)

< 0.001

Median length of stay (LOS)

3 days

5 days

< 0.001

Median total charges (TOTCHG)

$32,037

$44,092

< 0.001

Mean^a LOS (Standard deviation)

3.99 days (4.64)

7.10 days (8.40)

< 0.001

Mean^a TOTCHG (SD)

$49,722 (71,486)

$77,048 (133,027)

< 0.001

**Table 4.** Multivariate Analysis of Predictors of Mortality for Patients That Received a Colonoscopy During Hospitalization for an LGIB
Covariate/predictor	Adjusted odds ratio	95% confidence interval	P value
^aTransformation was performed on the value to make its distribution more normal, to have a more stable regression. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.
Age (square-root transformed value)^a	0.991	0.963	1.020	0.533
Gender (female)	1.006	0.926	1.092	0.894
Early colonoscopy	0.902	0.827	0.985	0.022
Race				< 0.001
White	0.789	0.627	0.992	0.043
Black	0.449	0.351	0.575	< 0.001
Hispanic	0.741	0.570	0.962	0.024
Asian/Pacific Islander	0.693	0.492	0.976	0.036
Native American	1.445	0.939	2.222	0.094
Type of insurance				< 0.001
Medicare	0.828	0.612	1.121	0.222
Medicaid	1.044	0.748	1.457	0.800
Private	0.743	0.539	1.023	0.069
Self-pay	1.271	0.853	1.895	0.238
No charge	0	0	0	0.991
Charlson Comorbidity Index	1.154	1.133	1.176	< 0.001
Hypovolemia/shock	2.961	2.694	3.255	< 0.001
IV blood product transfusion	1.147	1.057	1.244	< 0.001
AKI	0.306	0.282	0.333	< 0.001
Dialysis	3.584	3.041	4.225	< 0.001
Respiratory failure	21.916	19.873	24.17	< 0.001
Endoscopic intervention	0.486	0.257	0.919	0.026

Table 4. Multivariate Analysis of Predictors of Mortality for Patients That Received a Colonoscopy During Hospitalization for an LGIB

Covariate/predictor

Adjusted odds ratio

95% confidence interval

P value

Lower

Upper

^aTransformation was performed on the value to make its distribution more normal, to have a more stable regression. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.

Age (square-root transformed value)^a

0.991

0.963

1.020

0.533

Gender (female)

1.006

0.926

1.092

0.894

Early colonoscopy

0.902

0.827

0.985

0.022

Race

< 0.001

White

0.789

0.627

0.992

0.043

Black

0.449

0.351

0.575

< 0.001

Hispanic

0.741

0.570

0.962

0.024

Asian/Pacific Islander

0.693

0.492

0.976

0.036

Native American

1.445

0.939

2.222

0.094

Type of insurance

< 0.001

Medicare

0.828

0.612

1.121

0.222

Medicaid

1.044

0.748

1.457

0.800

Private

0.743

0.539

1.023

0.069

Self-pay

1.271

0.853

1.895

0.238

No charge

0.991

Charlson Comorbidity Index

1.154

1.133

1.176

< 0.001

Hypovolemia/shock

2.961

2.694

3.255

< 0.001

IV blood product transfusion

1.147

1.057

1.244

< 0.001

AKI

0.306

0.282

0.333

< 0.001

Dialysis

3.584

3.041

4.225

< 0.001

Respiratory failure

21.916

19.873

24.17

< 0.001

Endoscopic intervention

0.486

0.257

0.919

0.026

**Table 5.** Multivariate Analysis of Predictors of Length of Stay (LOS) for Patients That Received a Colonoscopy During Hospitalization for an LGIB
Covariate/predictor	Unstandardized coefficients after reverse transformation^a	95% confidence interval	P value
^aTransformation was performed on the value to make its distribution more normal and to have a more stable regression. The values in this table are reverse-transformed to make them more interpretable. ^bAge underwent square-root transformation making interpretation of numbers difficult in this case. For categorical variables, the +/- sign represents the direction of the effect, and the coefficient represents the percentage change attributed to the said covariate. For example, respiratory failure, if present, causes the LOS to increase by (1.671 - 1= 0.671) or 67.1%. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.
Constant	3.715 days	3.508	3.926	< 0.001
Age (square-root transformed value)^b	1.052	1.049	1.054	< 0.001
Gender (female)	1.028	1.023	1.033	< 0.001
Early colonoscopy	-1.44	-1.448	-1.435	< 0.001
Race
White	1.005	-1.006	1.016	0.433
Black	1.045	1.033	1.057	< 0.001
Hispanic	-1.011	-1.026	1	0.055
Asian/Pacific Islander	-1.039	-1.056	-1.023	< 0.001
Native American	-1.035	-1.062	-1.007	0.016
Type of insurance
Medicare	1.072	1.014	1.132	0.015
Medicaid	1.167	1.104	1.233	< 0.001
Private	1.072	1.014	1.132	0.016
Self-pay	1.084	1.026	1.148	0.005
No charge	1.007	-1.062	1.074	0.864
Charlson Comorbidity Index	1.045	1.042	1.045	< 0.001
Hypovolemia/shock	1.256	1.245	1.265	< 0.001
IV blood product transfusion	1.135	1.132	1.14	< 0.001
AKI	1.239	1.233	1.247	< 0.001
Dialysis	1.183	1.167	1.199	< 0.001
Respiratory failure	1.671	1.644	1.698	< 0.001
Endoscopic intervention	1.268	1.236	1.297	< 0.001
Weekend admission	-1.028	-1.033	-1.023	< 0.001

Table 5. Multivariate Analysis of Predictors of Length of Stay (LOS) for Patients That Received a Colonoscopy During Hospitalization for an LGIB

Covariate/predictor

Unstandardized coefficients after reverse transformation^a

95% confidence interval

P value

Lower

Upper

^aTransformation was performed on the value to make its distribution more normal and to have a more stable regression. The values in this table are reverse-transformed to make them more interpretable. ^bAge underwent square-root transformation making interpretation of numbers difficult in this case. For categorical variables, the +/- sign represents the direction of the effect, and the coefficient represents the percentage change attributed to the said covariate. For example, respiratory failure, if present, causes the LOS to increase by (1.671 - 1= 0.671) or 67.1%. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.

Constant

3.715 days

3.508

3.926

< 0.001

Age (square-root transformed value)^b

1.052

1.049

1.054

< 0.001

Gender (female)

1.028

1.023

1.033

< 0.001

Early colonoscopy

-1.44

-1.448

-1.435

< 0.001

Race

White

1.005

-1.006

1.016

0.433

Black

1.045

1.033

1.057

< 0.001

Hispanic

-1.011

-1.026

0.055

Asian/Pacific Islander

-1.039

-1.056

-1.023

< 0.001

Native American

-1.035

-1.062

-1.007

0.016

Type of insurance

Medicare

1.072

1.014

1.132

0.015

Medicaid

1.167

1.104

1.233

< 0.001

Private

1.072

1.014

1.132

0.016

Self-pay

1.084

1.026

1.148

0.005

No charge

1.007

-1.062

1.074

0.864

Charlson Comorbidity Index

1.045

1.042

1.045

< 0.001

Hypovolemia/shock

1.256

1.245

1.265

< 0.001

IV blood product transfusion

1.135

1.132

1.14

< 0.001

AKI

1.239

1.233

1.247

< 0.001

Dialysis

1.183

1.167

1.199

< 0.001

Respiratory failure

1.671

1.644

1.698

< 0.001

Endoscopic intervention

1.268

1.236

1.297

< 0.001

Weekend admission

-1.028

-1.033

-1.023

< 0.001

**Table 6.** Multivariate Analysis of Predictors of Total Charges (TOTCHG) for Patients That Received a Colonoscopy During Hospitalization for an LGIB
Covariate/predictor	Reverse-transformed values of unstandardized coefficients^a	95% confidence interval	P value
^aTransformation was performed on the value to make its distribution more normal and to have a more stable regression. The values in this table are reverse-transformed to make them more interpretable. ^bAge underwent square-root transformation making interpretation of numbers difficult in this case. For categorical variables, the +/- sign represents the direction of the effect, and the coefficient represents the percentage change attributed to the said covariate. For example, respiratory failure, if present, causes the TOTCHG to increase by (2.466 - 1 = 1.466) or 146.6%. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.
Constant	16,982	15,631	18,450	< 0.001
Age (square-root transformed value)^b	1.052	1.050	1.054	< 0.001
Gender (female)	1.002	0.998	1.009	0.357
Early colonoscopy	-1.288	-1.294	-1.279	< 0.001
Race
White	1.153	1.135	1.172	< 0.001
Black	1.175	1.156	1.197	< 0.001
Hispanic	1.459	1.432	1.486	< 0.001
Asian/Pacific Islander	1.426	1.393	1.459	< 0.001
Native American	1.033	0.991	1.074	0.119
Type of insurance
Medicare	1.153	1.067	1.250	< 0.001
Medicaid	1.259	1.161	1.365	< 0.001
Private	1.183	1.091	1.282	< 0.001
Self-pay	1.194	1.102	1.297	< 0.001
No charge	1.186	1.079	1.306	< 0.001
Charlson Comorbidity Index	1.062	1.060	1.067	< 0.001
Hypovolemia/shock	1.514	1.496	1.531	< 0.001
IV blood product transfusion	1.186	1.18	1.194	< 0.001
AKI	1.312	1.303	1.321	< 0.001
Dialysis	1.253	1.230	1.279	< 0.001
Respiratory failure	2.466	2.410	2.523	< 0.001
Endoscopic intervention	1.250	1.205	1.294	< 0.001
Weekend admission	-1.019	-1.026	-1.011	< 0.001

Table 6. Multivariate Analysis of Predictors of Total Charges (TOTCHG) for Patients That Received a Colonoscopy During Hospitalization for an LGIB

Covariate/predictor

Reverse-transformed values of unstandardized coefficients^a

95% confidence interval

P value

Lower

Upper

^aTransformation was performed on the value to make its distribution more normal and to have a more stable regression. The values in this table are reverse-transformed to make them more interpretable. ^bAge underwent square-root transformation making interpretation of numbers difficult in this case. For categorical variables, the +/- sign represents the direction of the effect, and the coefficient represents the percentage change attributed to the said covariate. For example, respiratory failure, if present, causes the TOTCHG to increase by (2.466 - 1 = 1.466) or 146.6%. LGIB: lower gastrointestinal bleed; IV: intravenous; AKI: acute kidney injury.

Constant

16,982

15,631

18,450

< 0.001

Age (square-root transformed value)^b

1.052

1.050

1.054

< 0.001

Gender (female)

1.002

0.998

1.009

0.357

Early colonoscopy

-1.288

-1.294

-1.279

< 0.001

Race

White

1.153

1.135

1.172

< 0.001

Black

1.175

1.156

1.197

< 0.001

Hispanic

1.459

1.432

1.486

< 0.001

Asian/Pacific Islander

1.426

1.393

1.459

< 0.001

Native American

1.033

0.991

1.074

0.119

Type of insurance

Medicare

1.153

1.067

1.250

< 0.001

Medicaid

1.259

1.161

1.365

< 0.001

Private

1.183

1.091

1.282

< 0.001

Self-pay

1.194

1.102

1.297

< 0.001

No charge

1.186

1.079

1.306

< 0.001

Charlson Comorbidity Index

1.062

1.060

1.067

< 0.001

Hypovolemia/shock

1.514

1.496

1.531

< 0.001

IV blood product transfusion

1.186

1.18

1.194

< 0.001

AKI

1.312

1.303

1.321

< 0.001

Dialysis

1.253

1.230

1.279

< 0.001

Respiratory failure

2.466

2.410

2.523

< 0.001

Endoscopic intervention

1.250

1.205

1.294

< 0.001

Weekend admission

-1.019

-1.026

-1.011

< 0.001