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Background: A few previous paired studies (including ours) showed that African-American (AA) and Hispanic-American (HA) had similar pouch related outcomes after ileal pouch-anal anastomosis (IPAA). There is no previous data on pouch outcomes for Indian-American (IA) patients. Further, whether ethinicity differentially influences pouch related outcomes after IPAA has not been investigated.

Aim: To compare differences in outcomes after IPAA for ulcerative colitis (UC) for AA, HA, IA and Caucasian-American patients.

Methods: From a prospectively maintained Pouchitis Database, this historical cohort study identified and compared UC patients with different racial background (AA, HA, IA or Caucasian-american) who underwent IPAA. Pouch patients with familial adenomatous polyposis, and those with unknown or mixed racial background were excluded. CD of the pouch was diagnosed based on a combined assessment of endoscopic, histologic, and radiographic features. A total of 25 demographic and clinical variables were evaluated with both univariate and multivariable analyses.

Results: There were 22 IA, 26 AA, 37 HA and 822 Caucasian-American patients. Results of unvariable and multivariable analyses associated with characteristics and outcomes for the various groups are shown in Table 1 and Table 2, respectively.

Conclusion: Significant differences in the disease course of UC before colectomy such as disease extent, use of immunomodulator or biologics, and duration of UC exist between the various ethnic groups. Racial background is independently associated with the risk for developing CD of pouch with AA patients having a 11-fold and Caucasian-Americans an 8-fold higher risk of developing CD of pouch compared to IA UC patients undergoing IPAA surgery.

Risk factors for Post-Op Development of CD of the Pouch: Multivariable Logistic Regression Analysis

Factor	Odds Ratio (95% Confidence Interval)	p-value
African-American vs. Indian-American	11.2 (1.1, 1507.3	0.012
Caucasian-American vs. Indian-American	8.1 (1.10, 1040.0)	0.008
Hispanic-American vs. Indian-American	4.2 (0.40, 572.0)	0.091
Age at time of pouch creation (5 yr. increase)	0.87 (0.81, 0.93)	<0.0001
Pouch duration (5 yr. increase)	1.2 (1.08, 1.4)	0.002
Pre-operative diagnosis: CD vs. UC	6.6 (2.2, 21.5)	0.001
Family history of CD	2.0 (1.06, 3.6)	0.035

Descriptive characteristics of IPAA patients based on racial background

Factor	Caucasian-American (N=822)	African-American (N=26)	Indian-American (N=22)	Hispanic-American (N=37)	p-value
Male	458(55.7)	13(50.0)	10(45.5)	23(62.2)	0.59
Age at time of diagnosis (yrs.)	27.6±12.4	28.0±11.1	28.7±10.3	24.4±13.2	0.45
Age at time of IPAA surgery (yrs.)	36.2±13.9	33.3±11.6	36.7±11.9	32.9±13.5	0.39
Current age (yrs.)	46.2±14.2	39.5±9.3	43.7±13.5	41.9±15.0	0.027
Duration of UC from diagnosis to IPAA surgery (yrs.)	6.0[2.0,12.0]	5.0[2.0,7.0]	5.5[4.0,12.0]	8.0[2.0,11.0]	0.56
Smoking					0.026
. Never	630(76.6)	24(92.3)	22(100.0)	27(73.0)
. Ex-smoker	122(14.8)	2(7.7)	0	9(24.3)
. Current smoker	70(8.5)	0	0	1(2.7)
Chronic NSAID use	50(6.1)	5(19.2)	1(4.5)	2(5.4)	0.058
Family history
IBD	179(21.8)	1(3.8)	1(4.5)	10(27.0)	0.026
CD	53(6.4)	0	0	1(2.7)	0.25
UC	132(16.1)	1(3.8)	1(4.5)	9(24.3)	0.073
Indication for colectomy					0.083
. Refractory to medical therapy	716(87.1)	26(100.0)	20(90.9)	29(78.4)
. Dysplasia	106(12.9)	0	2(9.1)	8(21.6)
Pre-operative diagnosis					0.53
. UC	744(90.5)	26(100.0)	21(95.5)	35(94.6)
. IC	66(8.0)	0	1(4.5)	1(2.7)
. CD	12(1.5)	0	0	1(2.7)
Extent of ulcerative colitis					<0.001
. Pancolitis	777(94.5) 3	22(84.6)	15(71.4)1	35(94.6)
. Left-sided colitis/Proctitis	45(5.5)	4(15.4)	6(28.6)	2(5.4)
Fulminant colitis	88(10.7)	0	3(13.6)	4(10.8)	0.34
Pre-operative use of biologics	70(8.5)	4(15.4)	5(22.7) 4	0 3	0.015
Number of visits to pouch clinic	2.0[1.00,3.0] 3,4	1.00[1.00,2.0]	1.00[1.00,2.0] 1	1.00[0.00,2.0] 1	<0.001
Pouch type					0.7
. J	767(93.4)	26(100.0)	21(95.5)	36(97.3)
. S	25(3.0)	0	0	0
. Other	29(3.5)	0	1(4.5)	1(2.7)
Stage of pouch surgery					0.85
. 1	28(3.4)	0	0	0
. 2	626(76.2)	22(84.6)	16(84.2)	30(81.1)
. 3	120(14.6)	3(11.5)	3(15.8)	5(13.5)
. 4 or redo pouch	48(5.8)	1(3.8)	0	0
Post-operative use of immunomodulator	88(10.7)	2(7.7)	1(4.5)	2(5.4)	0.55
Post-operative use of biologics	75(9.1)	2(7.7)	1(4.5)	1(2.7)	0.5
Autoimmune disease	115(14.0)	4(15.4)	0	3(8.1)	0.2
Primary sclerosing cholangitis	43(5.2)	1(3.8)	1(4.5)	1(2.7)	0.9
Liver transplantation	8(0.97)	1(3.8)	0	1(2.7)	0.39
Significant comorbidities	65(7.9)	3(11.5)	0	2(5.4)	0.44
Final diagnosis					0.003
. Normal pouch	82(10.0)4	5(19.2)	7(31.8)	13(35.1) 1
. Irritable pouch syndrome	142(17.3)	4(15.4)	1(4.5)	5(13.5)
. Active pouchitis	164(20.0)	5(19.2)	7(31.8)	6(16.2)
. Refractory pouchitis	107(13.0)	1(3.8)	3(15.8)	5(13.5)
. Crohn’s pouch	164(20.0)	5(19.2)	0	4(10.8)
. Cuffitis	83(10.1)	2(7.7)	1(4.5)	2(5.4)
. Surgical complications	78(9.5)	4(15.4)	3(15.8)	2(5.4)
. Anismus	2(0.24)	0	0	0
Extra-intestinal manifestations	314(38.2)	7(26.9)	6(27.3)	9(24.3)	0.16
Post-op hospitalization	133(16.2)	4(15.4)	6(27.3)	8(21.6)	0.46
Pouch failure	62(7.5)	3(11.5)	4(18.2)	2(5.4)	0.24
Follow up of Pouch Failure (yrs.)	9.0[5.0,14.0] 2,3	4.5[2.0,10.0] 1	4.0[2.0,10.0] 1	9.0[4.0,13.0]	<0.001

Values presented as Mean ± SD with ANOVA; Median [P25, P75] or Median (min, max) with Kruskal-Wallis test, o r N (%) with Pearson's chi-square test unless otherwise stated. 1: Significantly different from Caucasian 2: Significantly different from African-Am 3: Significantly different from Indian 4: Significantly different from Hispanic