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 188-199

Readmissions After Biliary Acute Pancreatitis: Analysis of the Nationwide Readmissions Database

**Table 1.** Demographics and Hospital Characteristics of Index Hospitalizations
Variable	No procedure	Only ERCP	Only cholecystectomy	ERCP and cholecystectomy	P-value
CCI: Charlson comorbidity index; ERCP: endoscopic retrograde cholangiopancreatography; MHOI: median household income for ZIP code; SD: standard deviation from the mean.
Number of hospitalizations	42,633 (33.5%)	13,802 (10.8%)	55,359 (43.5%)	15,523 (12.2%)
Mean age (years ± SD)	60.9 ± 19.9	63.9 ± 18.6	53.9 ± 19.5	56.5 ± 19.7	< 0.001
Age categories (%)					< 0.001
Young adults	21.1	15.9	32.2	28.2
Middle-aged	32.7	30.7	35.6	32.4
Elderly	46.2	53.5	32.2	39.4
Female (%)	55.9	55.8	62.6	58.7	< 0.001
CCI score (%)					< 0.001
0	39.8	39.1	53.1	51.6
1	25.0	25.7	25.1	24.4
2	13.8	13.2	10.7	11.3
≥ 3	21.5	22.0	11.1	12.7
Mean CCI	1.5	1.5	0.9	1.0
Primary payer (%)					< 0.001
Medicare	49.8	55.4	35.4	41.6
Medicaid	15.8	11.8	18.6	17.1
Private insurance	30.0	29.1	40.1	35.9
Self-pay	4.4	3.6	6.0	5.5
MHOI quartile (%)					< 0.001
1	26.5	24.4	28.4	27.4
2	27.8	29.7	27.8	27.4
3	25.0	25.7	25.4	25.7
4	20.6	20.2	18.4	19.5
Comorbidities (%)
Myocardial infarction	6.6	6.7	3.6	3.8	< 0.001
Congestive heart failure	12.2	12.8	6.0	7.0	< 0.001
Peripheral vascular disease	6.5	6.8	3.5	3.9	< 0.001
Cerebrovascular disease	2.5	2.3	1.4	1.7	< 0.001
Dementia	5.3	4.9	1.9	2.0	< 0.001
Chronic pulmonary disease	15.9	16.8	13.5	13.0	< 0.001
Rheumatologic disease	2.2	2.1	1.6	2.0	< 0.001
Peptic ulcer disease	1.5	3.6	0.9	2.9	< 0.001
Mild liver disease	11.9	9.9	11.7	11.2	< 0.001
Diabetes without complications	18.4	17.2	15.6	14.6	< 0.001
Diabetes with complications	7.8	8.1	5.1	5.4	< 0.001
Hemiplegia/paraplegia	0.3	0.4	0.3	0.4	0.357
Renal disease	14.0	14.4	7.7	8.9	< 0.001
Any malignancy	2.7	2.7	1.4	1.8	< 0.001
Moderate or severe liver disease	2.0	2.1	0.3	0.6	< 0.001
Metastatic solid tumor	1.0	1.4	0.4	0.4	< 0.001
HIV/AIDS	0.3	0.1	0.2	0.1	0.002
Hospital characteristics
Hospital bed size (%)					< 0.001
Small	21.2	13.7	18.6	13.9
Medium	29.5	29.3	29.0	28.3
Large	49.4	57.0	52.4	57.8
Hospital teaching status and location (%)					< 0.001
Metropolitan non-teaching	26.0	22.7	27.2	25.8
Metropolitan teaching	63.2	73.8	64.2	70.8
Non-metropolitan	10.9	3.5	8.6	3.4

Table 1. Demographics and Hospital Characteristics of Index Hospitalizations

Variable

No procedure

Only ERCP

Only cholecystectomy

ERCP and cholecystectomy

P-value

CCI: Charlson comorbidity index; ERCP: endoscopic retrograde cholangiopancreatography; MHOI: median household income for ZIP code; SD: standard deviation from the mean.

Number of hospitalizations

42,633 (33.5%)

13,802 (10.8%)

55,359 (43.5%)

15,523 (12.2%)

Mean age (years ± SD)

60.9 ± 19.9

63.9 ± 18.6

53.9 ± 19.5

56.5 ± 19.7

< 0.001

Age categories (%)

< 0.001

Young adults

21.1

15.9

32.2

28.2

Middle-aged

32.7

30.7

35.6

32.4

Elderly

46.2

53.5

32.2

39.4

Female (%)

55.9

55.8

62.6

58.7

< 0.001

CCI score (%)

< 0.001

39.8

39.1

53.1

51.6

25.0

25.7

25.1

24.4

13.8

13.2

10.7

11.3

≥ 3

21.5

22.0

11.1

12.7

Mean CCI

1.5

0.9

1.0

Primary payer (%)

< 0.001

Medicare

49.8

55.4

35.4

41.6

Medicaid

15.8

11.8

18.6

17.1

Private insurance

30.0

29.1

40.1

35.9

Self-pay

4.4

3.6

6.0

5.5

MHOI quartile (%)

< 0.001

26.5

24.4

28.4

27.4

27.8

29.7

27.8

27.4

25.0

25.7

25.4

25.7

20.6

20.2

18.4

19.5

Comorbidities (%)

Myocardial infarction

6.6

6.7

3.6

3.8

< 0.001

Congestive heart failure

12.2

12.8

6.0

7.0

< 0.001

Peripheral vascular disease

6.5

6.8

3.5

3.9

< 0.001

Cerebrovascular disease

2.5

2.3

1.4

1.7

< 0.001

Dementia

5.3

4.9

1.9

2.0

< 0.001

Chronic pulmonary disease

15.9

16.8

13.5

13.0

< 0.001

Rheumatologic disease

2.2

2.1

1.6

2.0

< 0.001

Peptic ulcer disease

1.5

3.6

0.9

2.9

< 0.001

Mild liver disease

11.9

9.9

11.7

11.2

< 0.001

Diabetes without complications

18.4

17.2

15.6

14.6

< 0.001

Diabetes with complications

7.8

8.1

5.1

5.4

< 0.001

Hemiplegia/paraplegia

0.3

0.4

0.3

0.4

0.357

Renal disease

14.0

14.4

7.7

8.9

< 0.001

Any malignancy

2.7

1.4

1.8

< 0.001

Moderate or severe liver disease

2.0

2.1

0.3

0.6

< 0.001

Metastatic solid tumor

1.0

1.4

0.4

< 0.001

HIV/AIDS

0.3

0.1

0.2

0.1

0.002

Hospital characteristics

Hospital bed size (%)

< 0.001

Small

21.2

13.7

18.6

13.9

Medium

29.5

29.3

29.0

28.3

Large

49.4

57.0

52.4

57.8

Hospital teaching status and location (%)

< 0.001

Metropolitan non-teaching

26.0

22.7

27.2

25.8

Metropolitan teaching

63.2

73.8

64.2

70.8

Non-metropolitan

10.9

3.5

8.6

3.4

**Table 2.** Outcomes of Index Hospitalizations
Variable	No procedure	Only ERCP	Only cholecystectomy	ERCP and cholecystectomy
aMD: adjusted mean difference for age categories and sex relative to no procedure group; aOR: adjusted odds ratio for age categories and sex relative no procedure group; CI: confidence interval; ERCP: endoscopic retrograde cholangiopancreatography; LOS: length of hospital stay; SE: standard error; THC: total hospital charge; USD: United States dollar.
Mortality
Mortality rate (%)	1.6	1.4	0.2	0.3
aOR (95% CI)	-	0.82 (0.63 - 1.06)	0.18 (0.13 - 0.24)	0.23 (0.15 - 0.36)
P-value	-	0.123	< 0.001	< 0.001
LOS
Mean LOS in days (SE)	4.7 (0.05)	6.1 (0.10)	5.0 (0.03)	5.9 (0.06)
aMD (95% CI)	-	1.31 (1.10 - 1.52)	0.45 (0.34 - 0.56)	1.31 (1.16 - 1.47)
P-value	-	< 0.001	< 0.001	< 0.001
Hospital charges
Mean THC in USD (SE)	42,438 (719.2)	69,194 (1,516.4)	61,845 (639.7)	83,593 (1,231.6)
aMD (95% CI)	-	25,999 (23,036 - 28,962)	21,512 (19,981 - 23,043)	42,249 (39,744 - 44,753)
P-value	-	< 0.001	< 0.001	< 0.001

Table 2. Outcomes of Index Hospitalizations

Variable

No procedure

Only ERCP

Only cholecystectomy

ERCP and cholecystectomy

aMD: adjusted mean difference for age categories and sex relative to no procedure group; aOR: adjusted odds ratio for age categories and sex relative no procedure group; CI: confidence interval; ERCP: endoscopic retrograde cholangiopancreatography; LOS: length of hospital stay; SE: standard error; THC: total hospital charge; USD: United States dollar.

Mortality

Mortality rate (%)

1.6

1.4

0.2

0.3

aOR (95% CI)

0.82 (0.63 - 1.06)

0.18 (0.13 - 0.24)

0.23 (0.15 - 0.36)

P-value

0.123

< 0.001

LOS

Mean LOS in days (SE)

4.7 (0.05)

6.1 (0.10)

5.0 (0.03)

5.9 (0.06)

aMD (95% CI)

1.31 (1.10 - 1.52)

0.45 (0.34 - 0.56)

1.31 (1.16 - 1.47)

P-value

< 0.001

Hospital charges

Mean THC in USD (SE)

42,438 (719.2)

69,194 (1,516.4)

61,845 (639.7)

83,593 (1,231.6)

aMD (95% CI)

25,999 (23,036 - 28,962)

21,512 (19,981 - 23,043)

42,249 (39,744 - 44,753)

P-value

< 0.001

**Table 3.** Most Common Principal Diagnoses for Readmissions
Principal readmission diagnosis	Proportion (%)
Biliary acute pancreatitis without necrosis or infection	10.7
Acute pancreatitis without necrosis or infection, unspecified	8.0
Sepsis, unspecified organism	6.2
Pseudocyst of pancreas	2.8
Calculus of gallbladder with acute cholecystitis without obstruction	2.0
Other postprocedural complications and disorders of the digestive system	1.7
Acute kidney failure, unspecified	1.5
Acute pancreatitis with uninfected necrosis, unspecified	1.5
Biliary acute pancreatitis with uninfected necrosis	1.4
Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease	1.0

Table 3. Most Common Principal Diagnoses for Readmissions

Principal readmission diagnosis

Proportion (%)

Biliary acute pancreatitis without necrosis or infection

10.7

Acute pancreatitis without necrosis or infection, unspecified

8.0

Sepsis, unspecified organism

6.2

Pseudocyst of pancreas

2.8

Calculus of gallbladder with acute cholecystitis without obstruction

2.0

Other postprocedural complications and disorders of the digestive system

1.7

Acute kidney failure, unspecified

1.5

Acute pancreatitis with uninfected necrosis, unspecified

1.5

Biliary acute pancreatitis with uninfected necrosis

1.4

Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease

1.0

**Table 4.** Demographics and Hospital Characteristics of Readmissions
Variable	No procedure	Only ERCP	Only cholecystectomy	ERCP and cholecystectomy	P-value
^aPercentage of readmissions for each procedural group after index hospitalization. CCI: Charlson Comorbidity Index; ERCP: endoscopic retrograde cholangiopancreatography; MHOI: median household income for ZIP code; SD: standard deviation from the mean; HIV: human immunodeficiency virus; AIDS: acquired immune deficiency syndrome.
Readmission^a (%)	15.0	13.0	6.5	5.8
Mean age (years ± SD)	61.5 ± 19.0	57.7 ± 19.7	57.8 ± 19.5	57.2 ± 19.7	< 0.001
Age categories (%)					< 0.001
Young adults	19.0	25.9	25.0	27.2
Middle-aged	33.4	34.1	34.7	31.4
Elderly	47.6	40.2	40.3	41.4
Female (%)	51.7	55.5	51.9	52.3	0.355
CCI score (%)					< 0.001
0	31.2	41.7	42.3	46.8
1	22.1	23.1	24.3	21.9
2	14.2	12.5	13.5	15.2
≥ 3	32.5	22.7	20.0	16.1
Mean CCI	2.0	1.5	1.4	1.2	< 0.001
Primary payer (%)					< 0.001
Medicare	54.3	45.2	46.5	48.6
Medicaid	16.2	19.8	17.5	17.2
Private insurance	25.4	31.6	31.1	30.5
Self-pay	4.1	3.4	4.8	3.8
MHOI quartile (%)					0.074
1	29.5	27.2	24.0	28.4
2	28.8	28.0	29.8	30.8
3	24.4	25.0	25.7	25.1
4	17.3	19.9	20.5	15.7
Comorbidities (%)
Myocardial infarction	8.5	4.9	5.3	6.1	< 0.001
Congestive heart failure	19.4	12.0	11.0	10.1	< 0.001
Peripheral vascular disease	7.0	4.5	5.5	3.5	0.022
Cerebrovascular disease	4.4	1.8	2.4	1.3	< 0.001
Dementia	5.1	3.6	2.5	3.1	0.003
Chronic pulmonary disease	18.8	16.3	17.1	15.2	0.186
Rheumatologic disease	2.5	2.3	2.2	2.8	0.946
Peptic ulcer disease	3.7	4.2	1.5	3.3	0.004
Mild liver disease	7.8	7.5	9.9	10.9	0.109
Diabetes without complications	20.0	18.6	18.5	12.5	0.049
Diabetes with complications	12.2	6.8	7.2	5.2	< 0.001
Hemiplegia/paraplegia	1.0	0.1	0.4	0.8	0.029
Renal disease	20.5	12.4	13.6	11.8	< 0.001
Any malignancy	4.6	6.9	3.7	1.9	0.008
Moderate or severe liver disease	3.1	3.8	1.4	2.2	0.019
Metastatic solid tumor	2.6	1.1	1.3	0.8	0.004
HIV/AIDS	0.5	0.4	0.0	0.3	0.236
Hospital characteristics
Hospital bed size (%)					0.002
Small	16.5	10.3	17.7	15.6
Medium	26.8	27.1	28.1	28.7
Large	56.7	62.7	54.2	55.7
Hospital teaching status and location (%)					< 0.001
Metropolitan non-teaching	22.8	20.4	24.3	21.2
Metropolitan teaching	69.3	76.1	68.2	75.1
Non-metropolitan	7.9	3.5	7.5	3.7

Table 4. Demographics and Hospital Characteristics of Readmissions

Variable

No procedure

Only ERCP

Only cholecystectomy

ERCP and cholecystectomy

P-value

^aPercentage of readmissions for each procedural group after index hospitalization. CCI: Charlson Comorbidity Index; ERCP: endoscopic retrograde cholangiopancreatography; MHOI: median household income for ZIP code; SD: standard deviation from the mean; HIV: human immunodeficiency virus; AIDS: acquired immune deficiency syndrome.

Readmission^a (%)

15.0

13.0

6.5

5.8

Mean age (years ± SD)

61.5 ± 19.0

57.7 ± 19.7

57.8 ± 19.5

57.2 ± 19.7

< 0.001

Age categories (%)

< 0.001

Young adults

19.0

25.9

25.0

27.2

Middle-aged

33.4

34.1

34.7

31.4

Elderly

47.6

40.2

40.3

41.4

Female (%)

51.7

55.5

51.9

52.3

0.355

CCI score (%)

< 0.001

31.2

41.7

42.3

46.8

22.1

23.1

24.3

21.9

14.2

12.5

13.5

15.2

≥ 3

32.5

22.7

20.0

16.1

Mean CCI

2.0

1.5

1.4

1.2

< 0.001

Primary payer (%)

< 0.001

Medicare

54.3

45.2

46.5

48.6

Medicaid

16.2

19.8

17.5

17.2

Private insurance

25.4

31.6

31.1

30.5

Self-pay

4.1

3.4

4.8

3.8

MHOI quartile (%)

0.074

29.5

27.2

24.0

28.4

28.8

28.0

29.8

30.8

24.4

25.0

25.7

25.1

17.3

19.9

20.5

15.7

Comorbidities (%)

Myocardial infarction

8.5

4.9

5.3

6.1

< 0.001

Congestive heart failure

19.4

12.0

11.0

10.1

< 0.001

Peripheral vascular disease

7.0

4.5

5.5

3.5

0.022

Cerebrovascular disease

4.4

1.8

2.4

1.3

< 0.001

Dementia

5.1

3.6

2.5

3.1

0.003

Chronic pulmonary disease

18.8

16.3

17.1

15.2

0.186

Rheumatologic disease

2.5

2.3

2.2

2.8

0.946

Peptic ulcer disease

3.7

4.2

1.5

3.3

0.004

Mild liver disease

7.8

7.5

9.9

10.9

0.109

Diabetes without complications

20.0

18.6

18.5

12.5

0.049

Diabetes with complications

12.2

6.8

7.2

5.2

< 0.001

Hemiplegia/paraplegia

1.0

0.1

0.4

0.8

0.029

Renal disease

20.5

12.4

13.6

11.8

< 0.001

Any malignancy

4.6

6.9

3.7

1.9

0.008

Moderate or severe liver disease

3.1

3.8

1.4

2.2

0.019

Metastatic solid tumor

2.6

1.1

1.3

0.8

0.004

HIV/AIDS

0.5

0.4

0.0

0.3

0.236

Hospital characteristics

Hospital bed size (%)

0.002

Small

16.5

10.3

17.7

15.6

Medium

26.8

27.1

28.1

28.7

Large

56.7

62.7

54.2

55.7

Hospital teaching status and location (%)

< 0.001

Metropolitan non-teaching

22.8

20.4

24.3

21.2

Metropolitan teaching

69.3

76.1

68.2

75.1

Non-metropolitan

7.9

3.5

7.5

3.7

**Table 5.** Predictors of Readmissions
Variable	aHR	95% confidence interval	P-value
^aRelative to no procedure. ^bRelative to male. ^cRelative to young adults. ^dRelative to lowest income. ^eRelative to Medicare. aHR: adjusted hazard ratio; ERCP: endoscopic retrograde cholangiopancreatography; HIV: human immunodeficiency virus; AIDS: acquired immune deficiency syndrome.
ERCP only*^a	0.86	0.80 - 0.93	< 0.001
Cholecystectomy only^a	0.47	0.44 - 0.50	< 0.001
ERCP + cholecystectomy^a	0.40	0.36 - 0.44	< 0.001
Female^b	0.82	0.78 - 0.87	< 0.001
Middle-aged^c	1.04	0.96 - 1.12	0.331
Elderly^c	0.82	0.74 - 0.91	< 0.001
Highest income quartile^d	0.89	0.82 - 0.97	0.006
Private insurance^e	0.71	0.65 - 0.78	< 0.001
Myocardial infarction	0.98	0.88 - 1.09	0.683
Congestive heart failure	1.26	1.17 - 1.37	< 0.001
Peripheral vascular disease	1.03	0.92 - 1.14	0.661
Cerebrovascular disease	1.27	1.08 - 1.48	0.003
Dementia	0.92	0.81 - 1.05	0.242
Chronic pulmonary disease	1.22	1.14 - 1.31	< 0.001
Rheumatologic disease	1.33	1.13 - 1.55	< 0.001
Peptic ulcer disease	1.51	1.28 - 1.78	< 0.001
Diabetes without complications	1.15	1.07 - 1.23	< 0.001
Diabetes with complications	1.10	1.05 - 1.15	< 0.001
Hemiplegia/paraplegia	1.15	0.94 - 1.41	0.173
Renal disease	1.18	1.13 - 1.23	< 0.001
Any malignancy	1.22	1.14 - 1.32	< 0.001
Moderate or severe liver disease	1.11	1.05 - 1.18	< 0.001
Metastatic solid tumor	1.12	1.08 - 1.17	< 0.001
HIV/AIDS	1.09	1.03 - 1.64	0.006
Discharge against medical advice	1.76	1.51 - 2.06	< 0.001

Table 5. Predictors of Readmissions

Variable

aHR

95% confidence interval

P-value

^aRelative to no procedure. ^bRelative to male. ^cRelative to young adults. ^dRelative to lowest income. ^eRelative to Medicare. aHR: adjusted hazard ratio; ERCP: endoscopic retrograde cholangiopancreatography; HIV: human immunodeficiency virus; AIDS: acquired immune deficiency syndrome.

ERCP only*^a

0.86

0.80 - 0.93

< 0.001

Cholecystectomy only^a

0.47

0.44 - 0.50

< 0.001

ERCP + cholecystectomy^a

0.40

0.36 - 0.44

< 0.001

Female^b

0.82

0.78 - 0.87

< 0.001

Middle-aged^c

1.04

0.96 - 1.12

0.331

Elderly^c

0.82

0.74 - 0.91

< 0.001

Highest income quartile^d

0.89

0.82 - 0.97

0.006

Private insurance^e

0.71

0.65 - 0.78

< 0.001

Myocardial infarction

0.98

0.88 - 1.09

0.683

Congestive heart failure

1.26

1.17 - 1.37

< 0.001

Peripheral vascular disease

1.03

0.92 - 1.14

0.661

Cerebrovascular disease

1.27

1.08 - 1.48

0.003

Dementia

0.92

0.81 - 1.05

0.242

Chronic pulmonary disease

1.22

1.14 - 1.31

< 0.001

Rheumatologic disease

1.33

1.13 - 1.55

< 0.001

Peptic ulcer disease

1.51

1.28 - 1.78

< 0.001

Diabetes without complications

1.15

1.07 - 1.23

< 0.001

Diabetes with complications

1.10

1.05 - 1.15

< 0.001

Hemiplegia/paraplegia

1.15

0.94 - 1.41

0.173

Renal disease

1.18

1.13 - 1.23

< 0.001

Any malignancy

1.22

1.14 - 1.32

< 0.001

Moderate or severe liver disease

1.11

1.05 - 1.18

< 0.001

Metastatic solid tumor

1.12

1.08 - 1.17

< 0.001

HIV/AIDS

1.09

1.03 - 1.64

0.006

Discharge against medical advice

1.76

1.51 - 2.06

< 0.001