Ileal pouch-anal anastomosis (IPAA) has been widely accepted as a radical surgery for ulcerative colitis (UC).¹ Previous studies have demonstrated that IPAA significantly improved the quality of life (QOL) as it can restore intestinal continuity and avoid permanent ostomy by pouch construction.^2-4 However, our previous study indicated that the technically demanding operation was associated with serious surgical complications, which may have a detrimental effect on the long-term QOL.⁵

IPAA can remove the affected colorectum and create an ileal reservoir. Among the “J”, “W”, “S” and recently reported “D” pouch, J pouch configuration is the most commonly used configuration of IPAA due to easy construction and satisfactory clinical outcomes.^6,7 The length of distal ileum for pouch creation mainly determined the pouch volume, which is associated with bowel and pouch function.⁸ However, it is still unclear what length of pouch could make patients achieve the best long-term prognosis.⁹ Few studies with long follow-up period reported the relationship between pouch length and post-IPAA complications and long-term QOL.

In this study, we mainly aimed to determine whether pouch length was associated with the clinical outcomes by analyzing the postoperative long-term QOL and complications in patients with pouches of different lengths.

1. Study design and patients

A total of 221 patients with UC who underwent IPAA from January 2008 to September 2022 at our four inflammatory bowel disease surgery centers affiliated to China UC Pouch Center Union were evaluated in this study. As we previously reported, we collected the data by the prospectively maintained, institutional review board-approved pouch database.⁵ In our institute, we recommended a pouchoscopic examination once a year for those patients who had risks for pouch malignant transformation or complications. The Ethics Committee of Xinhua Hospital has reviewed and approved this study protocol (approval number: XHEC-D-2022-093). All patients signed informed consent forms.

2. Inclusion and exclusion criteria

Patients who were diagnosed with UC who underwent IPAA with J pouch construction and had complete data were included in this study. The exclusion criteria were patients with Crohn’s disease or familial adenomatous polyposis, without pouch creation and with incomplete data and loss of follow-up.

3. Preoperative and postoperative QOL assessment

To assess the preoperative and post-IPAA QOL, the Cleveland Global Quality of Life (CGQL) instrument was used for evaluation.¹⁰ The preoperative CGQL was collected after admission by questionnaires; post-IPAA CGQL was obtained from the most recent postoperative outpatient follow-up. CGQL was classified into three items as follows: current QOL (0 to 10 scores), current quality of health (0 to 10 scores) and current energy level (0 to 10 scores). Then the ultimate CGQL was obtained from the cumulative score divided by 30. As reported in our previous study,⁵ an increase of more than or less than 50% in postoperative CGQL compared to preoperative CGQL was considered as significantly improved long-term QOL or impaired long-term QOL in our study.

4. Pouch construction and the measurement of pouch length

The procedure of IPAA is homogenized, standardized, and normalized in our institute and performed by a specific and experienced colorectal surgeon in each center. Thus, the pouch length was mainly decided by the surgeons’ own experience as well as the intraoperative situation.

The length of cutting line of the anastomosis was assessed and measured intraoperatively to record as the pouch length. In our present retrospective multicenter study, we concluded the length of pouch was nearly 14±2 cm or 22±2 cm when we used 3 or 4-5 endoscopic linear cutter reloads, measured by using Endo GIA60, a laparoscopic stapler for construction J pouch. Pouch length was intraoperatively recorded and finally obtained by measuring the side-to-side anastomosis’s cutting line of the pouch body. Based on the medical records in the cohort database, we found the main two sizes of pouch, the length of 14±2 and 22±2 cm, were constructed in our inflammatory bowel disease surgery centers. According to the median lengths of the two sizes of pouch, 14.0 cm (interquartile range [IQR], 14.0 to 15.0 cm) and 22.0 cm (IQR, 20.0 to 24.0 cm), we categorized these pouches as short and long J pouch.

5. Data evaluation

Primary endpoints in this study were the occurrence of late postoperative complications or the impaired long-term QOL. Complications developed within 1 month after pouch surgery were defined as the early surgical complications. Pouchitis, pouch failure, defecation disorder, postoperative late intestinal obstruction, pouch-vagina leak, anastomotic stricture and sexual dysfunction were categorized as the late post-IPAA complications, which occurred more than 1 month after IPAA. Preoperative medical therapies and the value of laboratory results, such as hemoglobin and albumin were collected preoperatively.

6. Statistical analysis

Statistical analysis in this study was performed using the SPSS version 22.0 (IBM Corp., Armonk, NY, USA) and GraphPad Prism 8.0 (San Diego, CA, USA). Statistical data were represented as mean and standard deviations, or the median and IQR appropriately. To compare the significance of continuous variables, the two-sample Student t-test was performed. The Wilcoxon rank-sum test was used to compare the ranked variables. Additionally, categorical variables were analyzed by the chi-square or Fisher exact test. Variables with significant differences in the univariate analysis were then selected for the multivariate logistic regression analysis. In this study, we considered a p-value <0.05 significant with a two-sided test and confidence intervals (CIs) set at 95%.

1. Baseline characteristics

In the whole cohort of 221 UC patients, three patients underwent ileostomy without pouch construction, and 10 were lost to follow-up. In the present study, a total of 208 eligible patients who met the inclusion criteria were ultimately enrolled. The schematic flow diagram of this study is shown in Fig. 1. The overall baseline characteristics and the comparative analysis between the short and long J pouch groups were presented in Table 1. In the whole cohort, the median follow-up time was 6.0 years (IQR, 2.3 to 9.0 years). Of these patients, 94 patients had relatively short pouches (45.2%) with a median length of 14.0 cm (IQR, 14.0 to 15.0 cm) and 114 had long ileal pouches (54.8%) with a median length of 22.0 cm (IQR, 20.0 to 24.0 cm). There were more patients with intraoperative blood loss more than 200 mL in long J pouch group than in short J pouch group (p<0.001). There was no significant difference in other baseline characteristics between the short and long pouch groups (Table 1).

Figure 1. Schematic flow diagram of the present study. UC, ulcerative colitis; IPAA, Ileal pouch-anal anastomosis; QOL, quality of life.

Table 1 . Main Baseline Patient Characteristics.

Variable	All cases (n=208)	Short J pouch group (n=94)	Long J pouch group (n=114)	p-value
Follow-up time, yr	6.0 (2.3–9.0)	6.0 (2.0–8.0)	7.0 (3.0–9.0)
Sex, male/female	109/99	54/40	55/59	0.186*
Age at diagnosis				0.740*
<40 yr	100 (48.1)	44 (46.8)	56 (49.1)
≥40 yr	108 (51.9)	50 (53.2)	58 (50.9)
Height				0.807*
<170 cm	112 (58.7)	56 (59.6)	66 (57.9)
≥170 cm	86 (41.3)	38 (40.4)	48 (42.1)
Body mass index				0.164*
≥18.5 kg/m2	143 (68.8)	60 (63.8)	83 (72.8)
<18.5 kg/m2	65 (31.2)	34 (36.2)	31 (27.2)
Disease duration				0.726*
<5 yr	139 (66.8)	64 (68.1)	75 (65.8)
≥5 yr	69 (33.2)	30 (31.9)	39 (34.2)
First occurrence				0.437†
Yes	31 (14.9)	16 (17.0)	15 (13.2)
No	177 (85.1)	78 (83.0)	99 (86.8)
Extent of ulcerative colitis				0.909†
E1 (proctitis)	37 (17.8)	18 (19.1)	19 (16.7)
E2 (left-sided colitis)	18 (8.7)	6 (6.4)	12 (10.5)
E3 (pancolitis)	153 (73.5)	70 (74.5)	83 (72.8)
Extraintestinal manifestation				0.169*
No	184 (88.5)	80 (85.1)	104 (91.2)
Yes	24 (11.5)	14 (14.9)	10 (8.8)
Mesalamine				0.539*
No	62 (29.8)	26 (27.7)	36 (31.6)
Yes	146 (70.2)	68 (72.3)	78 (68.4)
Immunomodulators				0.661*
No	147 (70.7)	65 (69.1)	82 (71.9)
Yes	61 (29.3)	29 (30.9)	32 (28.1)
Steroids				0.709*
No	79 (38.0)	37 (39.4)	42 (36.8)
Yes	129 (62.0)	57 (60.6)	72 (63.2)
Biologics				0.333*
No	178 (85.6)	78 (83.0)	100 (87.7)
Yes	30 (14.4)	16 (17.0)	14 (12.3)
Stage of surgery				0.633†
II-stage IPAA	132 (63.5)	58 (61.7)	74 (64.9)
III-stage IPAA	76 (36.5)	36 (38.3)	40 (35.1)
Surgical urgency				0.062†
Urgent surgery	20 (9.6)	13 (13.8)	7 (6.1)
Elective surgery	188 (90.4)	81 (86.2)	107 (93.9)
Surgical approach				0.275*
Open	61 (29.3)	24 (25.5)	37 (32.5)
Laparoscopic	147 (70.7)	70 (74.5)	77 (67.5)
Hemoglobin				0.697*
≥110 g/L	76 (36.5)	33 (35.1)	43 (37.7)
<110 g/L	132 (63.5)	61 (64.9)	71 (62.3)
Albumin				0.140*
≥35 g/L	98 (47.1)	39 (41.5)	59 (51.8)
<35 g/L	110 (52.9)	55 (58.5)	55 (48.2)
White blood cell				0.348*
<10×109/L	159 (76.4)	69 (73.4)	90 (78.9)
≥10×109/L	49 (23.6)	25 (26.6)	24 (21.1)
Hospitalization time				0.686*
<15 day	103 (49.5)	48 (51.1)	55 (48.2)
≥15 day	105 (50.5)	46 (48.9)	59 (51.8)
Intraoperative blood loss				<0.001*
<200 mL	139 (66.8)	78 (83.0)	61 (53.5)
≥200 mL	69 (33.2)	16 (17.0)	53 (46.5)

Data are presented as median (interquartile range) or number (%)..

IPAA, ileal pouch-anal anastomosis..

*Chi-square test; ^†Wilcoxon rank-sum test..

2. Post-IPAA complications

A total of 58 patients (27.9%) developed the early postoperative complications. Late postoperative complications occurred in 71 patients (34.1%). Of them, 58 (27.9%) developed pouchitis, 23 (11.1%) had increased defecation frequency, 10 (4.8%) developed late postoperative intestinal obstruction, seven (3.4%) had anastomotic stricture, four (1.9%) developed pouch-vagina leak, three (1.4%) experienced pouch failure, and only one (0.5%) developed sexual dysfunction (Table 2).

Table 2 . Main Postoperative Complications of Ileal Pouch-Anal Anastomosis.

Complication	No. (%)
Early postoperative complications
Early postoperative intestinal obstruction	31 (14.9)
Pouch and anastomotic bleeding	11 (5.3)
Pouch-anal anastomotic leak	4 (1.9)
Wound infection	16 (7.7)
Incision hernia	3 (1.4)
Late postoperative complications
Pouchitis	58 (27.9)
Pouch failure	3 (1.4)
Increased defecation frequency	23 (11.1)
Late postoperative intestinal obstruction	10 (4.8)
Pouch-vagina leak	4 (1.9)
Anastomotic stricture	7 (3.4)
Sexual dysfunction	1 (0.5)

3. Clinical outcomes in patients with J pouch configuration of different lengths

We first evaluated the effect of IPAA on postoperative outcomes in patients with UC. As shown in Fig. 2, the mean current QOL (pre vs post, 4.274 vs 7.481, p<0.001), current quality of health (pre vs post, 4.760 vs 7.505, p<0.001), current energy level (pre vs post, 5.106 vs 7.683, p<0.001) and ultimate CGQL scores (pre vs post, 0.472 vs 0.757, p<0.001) were all significantly improved after IPAA in the whole cohort.

Figure 2. Evaluation of the long-term QOL via the pre-IPAA and post-IPAA CGQL instrument. Three items of the CGQL instrument—current QOL (A), current quality of health (B), and current energy level (C)—and the overall CGQL scores (n=208) (D) were compared between the pre- and post-IPAA periods in the whole cohort. QOL, quality of life; IPAA, Ileal pouch-anal anastomosis; CGQL, Cleveland Global Quality of Life. *p<0.001.

To determine whether pouch length could affect clinical outcomes, we compared the postoperative complications and long-term QOL in patients with pouches of different lengths. As shown in Table 3, we found that patients in short J pouch group were likely to develop the late postoperative complications (p=0.042), mainly presented in more defecation frequency (p=0.003) and pouchitis (p=0.035). The significantly improved CGQL was more common in long J pouch group than in short J pouch group (p=0.015) (Table 3).

Table 3 . Analysis of the Clinical Outcomes in Patients with Short and Long Ileal J Pouches.

Variable	Short J pouch group (n=94)	Long J pouch group (n=114)	p-value
Early postoperative complications	25 (26.6)	33 (28.9)	0.707*
Late postoperative complications	39 (41.5)	32 (28.1)	0.042*
Increased defecation frequency			0.003*
No	77 (81.9)	108 (94.7)
Yes	17 (18.1)	6 (5.3)
Pouchitis			0.035*
No	61 (64.9)	89 (78.1)
Yes	33 (35.1)	25 (21.9)
Postoperative long-term intestinal obstruction			0.735†
No	90 (95.7)	108 (94.7)
Yes	4 (4.3)	6 (5.3)
Anastomotic stricture			0.156†
No	89 (94.7)	112 (98.2)
Yes	5 (5.3)	2 (1.8)
Postoperative CGQL score	0.725±0.135	0.783±0.139	0.003‡
Current QOL	7.128±1.648	7.772±1.574	0.004‡
Current quality of health	7.128±1.483	7.816±1.485	0.001‡
Current energy level	7.447±1.637	7.877±1.575	0.055‡
Significantly improved long-term QOL			0.015*
No	47 (50.0)	38 (33.3)
Yes	47 (50.0)	76 (66.7)

Data are presented as number (%) or mean±SD..

CGQL, Cleveland Global Quality of Life; QOL, quality of life..

*Chi-square test; ^†Fisher exact test; ^‡Two-sample Student t-test..

Although we found an obvious improvement of CGQL scores in short and long J pouch group (Fig. 3A and B), the post-IPAA current QOL (7.128 vs 7.772, p=0.004), current quality of health (7.128 vs 7.816, p=0.001) and ultimate CGQL scores (0.725 vs 0.783, p=0.003) were significantly impaired compared with those with long J pouch (Table 3, Fig. 3C-F). Collectively, these data demonstrated pouch length was associated with the clinical outcomes in patients underwent IPAA. Therefore, we speculated that short J pouch could be a risk factor for the development of late postoperative complications and impaired long-term QOL improvement.

Figure 3. Analysis of the effects of pouch length on the improvement in long-term post-IPAA QOL. Comparison of pre- and post-IPAA CGQL in patients with short J pouch (n=94) (A) and long J pouch (n=114) (B). Three items of the CGQL instrument—current QOL (C), current quality of health (D), and current energy level (E)—and the overall CGQL scores (F) were compared between the short and long J pouch groups. IPAA, Ileal pouch-anal anastomosis; QOL, quality of life; CGQL, Cleveland Global Quality of Life; NS, not significant. *p<0.01; ^†p<0.001.

4. Short J pouch configuration increased the risk for the late post-IPAA complications

Furthermore, we explored whether the short J pouch configuration could contribute to develop the late post-IPAA complications. The results of the univariate analysis indicated that recurrence of disease (p=0.002), pouch length (p=0.042), the value of preoperative white blood cell (WBC) count (p=0.031), hospitalization time (p=0.003), and intraoperative blood loss (p=0.009) were significantly associated with the late post-IPAA complications (Table 4). These significant variables in the univariate analysis were further analyzed in the multivariate logistic regression and demonstrated that recurrent UC (odds ratio [OR], 8.102; 95% CI, 2.259 to 29.602; p=0.001), short J pouch (OR, 3.100; 95% CI, 1.519 to 6.329; p=0.002), the preoperative total WBCs more than 10×10⁹/L (OR, 2.641; 95% CI, 1.243 to 5.609; p=0.012) and intraoperative blood loss ≥200 m: (OR, 3.484; 95% CI, 1.574 to 7.712; p=0.002) were independent risk factors for the development of late postoperative complications (Table 4). Taken together, these data indicated the short J pouch configuration could increase the risk to develop late post-IPAA complications and further affect the long-term QOL improvement.

Table 4 . Univariate and Multivariate Logistic Regression Analysis of Risk Factors for Late Postoperative Complications in Ulcerative Colitis Patients with IPAA.

Variable	Non-late postoperative complications group (n=137)	Late postoperative complications group (n=71)	Univariate analysis p-value		Multivariate logistic regression
					OR (95% CI)	p-value
Age at diagnosis
<40 yr	69 (50.4)	31 (43.7)	0.359*
≥40 yr	68 (49.6)	40 (56.3)
Body mass index			0.567*
≥18.5 kg/m2	96 (70.1)	47 (66.2)
<18.5 kg/m2	41 (29.9)	24 (33.8)
Disease duration			0.653*
<5 yr	93 (67.9)	46 (64.8)
≥5 yr	44 (32.1)	25 (35.2)
First occurrence			0.002†		8.102 (2.259–29.602)	0.001
Yes	28 (20.4)	3 (4.2)
No	109 (79.6)	68 (95.8)
Extent of ulcerative colitis			0.214†
E1 (proctitis)	27 (19.7)	10 (14.1)
E2 (left-sided colitis)	13 (9.5)	5 (7.0)
E3 (pancolitis)	97 (70.8)	56 (78.9)
Extraintestinal manifestation			0.712*
No	122 (89.1)	62 (87.3)
Yes	15 (10.9)	9 (12.7)
Mesalamine			0.183*
No	45 (32.8)	17 (23.9)
Yes	92 (67.2)	54 (76.1)
Immunomodulators			0.220*
No	93 (67.9)	54 (76.1)
Yes	44 (32.1)	17 (23.9)
Steroids			0.554*
No	54 (39.4)	25 (35.2)
Yes	83 (60.6)	46 (64.8)
Biologics			0.606*
No	116 (84.7)	62 (87.3)
Yes	21 (15.3)	9 (12.7)
Stage of surgery			0.373†
II-stage IPAA	84 (61.3)	48 (67.6)
III-stage IPAA	53 (38.7)	23 (32.3)
Surgical urgency			0.682†
Urgent surgery	14 (10.2)	6 (8.5)
Elective surgery	123 (89.8)	65 (91.5)
Surgical approach			0.705*
Open surgery	39 (28.5)	22 (31.0)
Laparoscopic surgery	98 (71.5)	49 (69.0)
Pouch length			0.042*		3.100 (1.519–6.329)	0.002
Short J pouch	55 (40.1)	39 (54.9)
Long J pouch	82 (59.9)	32 (45.1)
Hemoglobin			0.532*
≥110 g/L	48 (35.0)	28 (39.4)
<110 g/L	89 (65.0)	43 (60.6)
Albumin			0.104*
≥35 g/L	59 (43.1)	39 (54.9)
<35 g/L	78 (56.9)	32 (45.1)
White blood cell			0.031*		2.641 (1.243–5.609)	0.012
<10×109/L	111 (81.1)	48 (67.6)
≥10×109/L	26 (19.0)	23 (32.4)
Hospitalization time			0.003*		1.626 (0.820–3.226)	0.164
<15 day	78 (56.9)	25 (35.2)
≥15 day	59 (43.1)	46 (64,8)
Intraoperative blood loss			0.009*		3.484 (1.574–7.712)	0.002
<200 mL	100 (73.0)	39 (54.9)
≥200 mL	37 (27.0)	32 (45.1)

Data are presented as number (%)..

IPAA, ileal pouch-anal anastomosis; OR, odds ratio; CI, confidence interval..

*Chi-square test; ^†Wilcoxon rank-sum test..

5. Short J pouch configuration affected the postoperative long-term QOL

To further investigate whether short J pouch could impair postoperative long-term QOL, univariate analysis was performed. In this study, postoperative long-term QOL was significantly improved in 123 patients (59.1%), and relatively impaired in 85 patients (40.9%). We found that age at diagnosis (p=0.012), surgical approach (p=0.002), pouch length (p=0.015) and preoperative albumin value (p=0.046) were associated with the postoperative long-term QOL improvement (Table 5). These significant variables in univariate analysis were selected for the multivariate logistic regression analysis and determined that age at diagnosis more than 40 years old (OR, 2.214; 95% CI, 1.170 to 3.855; p=0.013), open surgery (OR, 3.268; 95% CI, 1.688 to 6.326; p<0.001) and short ileal pouch (OR, 2.221; 95% CI, 1.218 to 4.050; p=0.009) were independent contributing factors for the impaired long-term QOL (Table 5).

Table 5 . Univariate and Multivariate Logistic Regression Analysis of Risk Factors for Impaired Long-term QOL after IPAA.

Variable	Impaired long-term QOL group (n=85)	Significantly improved long-term QOL group (n=123)	Univariate analysis p-value		Multivariate logistic regression
					OR (95% CI)	p-value
Age at diagnosis			0.012*		2.214 (1.170–3.855)	0.013
<40 yr	32 (37.6)	68 (55.3)
≥40 yr	53 (62.4)	55 (44.7)
Body mass index			0.278*
≥18.5 kg/m2	62 (72.9)	81 (65.9)
<18.5 kg/m2	23 (27.1)	42 (34.1)
Disease duration			0.400*
<5 yr	54 (63.5)	85 (69.1)
≥5 yr	31 (36.5)	38 (30.9)
First occurrence			0.599†
Yes	14 (16.5)	17 (13.8)
No	71 (83.5)	106 (86.2)
Extent of ulcerative colitis			0.634†
E1 (proctitis)	14 (16.5)	23 (18.7)
E2 (left-sided colitis)	7 (8.2)	11 (8.9)
E3 (pancolitis)	64 (75.3)	89 (72.4)
Extraintestinal manifestation			0.599*
No	74 (87.1)	110 (89.4)
Yes	11 (12.9)	13 (10.6)
Mesalamine			0.411*
No	28 (32.9)	34 (27.6)
Yes	57 (67.1)	89 (72.4)
Immunomodulators			0.224*
No	64 (75.3)	83 (67.5)
Yes	21 (24.7)	40 (32.5)
Steroids			0.618*
No	34 (40.0)	45 (36.6)
Yes	51 (60.0)	78 (63.4)
Biologics			0.271*
No	70 (82.4)	108 (87.8)
Yes	15 (17.6)	15 (12.2)
Stage of surgery			0.757†
II-stage IPAA	55 (64.7)	77 (62.6)
III-stage IPAA	30 (35.3)	46 (37.4)
Surgical urgency			0.934†
Urgent surgery	8 (9.4)	12 (9.8)
Elective surgery	77 (90.6)	111 (90.2)
Surgical approach			0.002*		3.268 (1.688–6.326)	<0.001
Open surgery	35 (41.2)	26 (21.1)
Laparoscopic surgery	50 (58.8)	97 (78.9)
Pouch length			0.015*		2.221 (1.218-4.050)	0.009
Short J pouch	47 (55.3)	47 (38.2)
Long J pouch	38 (44.7)	76 (61.8)
Hemoglobin			0.783*
≥110 g/L	32 (37.6)	44 (35.8)
<110 g/L	53 (62.4)	79 (64.2)
Albumin			0.046*		1.784 (0.972–3.274)	0.062
≥35 g/L	33 (38.8)	65 (52.8)
<35 g/L	52 (61.2)	58 (47.2)
White blood cell			0.381*
<10×109/L	68 (80.0)	92 (74.8)
≥10×109/L	17 (20.0)	31 (25.2)
Intraoperative blood loss			0.589*
<200 mL	55 (64.7)	84 (68.3)
≥200 mL	30 (35.3)	39 (31.7)

Data are presented as number (%)..

QoL, quality of life; IPAA, ileal pouch-anal anastomosis; OR, odds ratio; CI, confidence interval..

*Chi-square test; ^†Wilcoxon rank-sum test..

The present study with a long follow-up period comprehensively and systematically analyzed the relationship between pouch length and clinical outcomes in UC patients. In this study, our findings indicated that patients with short pouch were less likely to achieve significantly improved long-term QOL and prone to develop the late postoperative complications, such as more defecation frequency and pouchitis. We further demonstrated that recurrent UC, short J pouch, high preoperative total WBCs and intraoperative blood loss ≥200 mL were contributing factors for the development of late post-IPAA complications. Moreover, short J pouch configuration, age at diagnosis more than 40 years old and open surgery were independent risk factors for impaired long-term QOL. Therefore, long J pouch configuration could be a considerable surgical option for pouch construction.

Previous studies indicated excessive blood loss was associated with increased mortality after colorectal surgery and length of hospital stay.^11,12 We also reported that patients with intraoperative blood loss ≥200 mL were prone to develop early surgical complications, which have a detrimental effect on the postoperative long-term outcomes.⁵ Patients with recurrent UC and high preoperative WBCs count were prone to suffer the chronic inflammation, which is associated with poor long-term outcomes and the development of postoperative complications after IPAA.¹³ We previously reported that older age at pouch surgery could contribute to poor long-term QOL after IPAA.⁵ Previous researches also indicated that older patients underwent pouch surgery were prone to develop complications, including increased stool frequency and fecal incontinence, which could impair their long-term QOL.^14-16 We also demonstrated that minimally invasive laparoscopic surgery could make patients achieve better prognoses.¹⁷ Additionally, we first indicated that short J pouch configuration could increase the risk to develop late complications and impair the improvement of postoperative long-term QOL.

It is still unclear whether pouch length is associated with the long-term prognosis after IPAA. Shibata et al.¹⁸ showed that patients with a long J pouch were prone to have less frequent stools. In our study, we compared the postoperative complications in patients with relatively short (14±2 cm) and long (22±2 cm) J pouch and demonstrated short J pouch make patients more likely to had more defecation frequency, which was consistent with researches which reported that stool frequency was negatively correlated with the pouch volume.^19-21 Miratashi Yazdi et al.²² reported that patients with short J pouch configuration (8±2 cm) were likely to have worse bowel function but obtained better QOL assessed by SF-36 questionnaire. However, our study indicated that patients with long J pouch were more likely to achieve significantly improved long-term QOL, which could be explained by the different scoring scale and the follow-up period in our study was much longer than this research. In addition to the increased frequency of stools, we also indicated pouchitis was more common in patients with short J pouch. Previous studies reported various risk factors for pouchitis.^23-27 Pouchitis could be described as the continuation and reactivation of UC disease processes.^28,29 It was known that microbiota dysbiosis exerts an important role in the development of pouchitis. A dysbiosis characterized by decreased gut microbiota diversity in patients underwent IPAA may contribute to an aberrant mucosal immune regulation to promote the development of pouchitis.³⁰ Sinha et al.³¹ reported that a secondary bile acid-producing species, Ruminococcaceae, was significantly decreased in pouchitis. Thus, increased defecation frequency or incontinence could promote the disruption of intestine homeostasis and further promote the development of microbiota dysbiosis³² then lead to the occurrence of pouchitis.^33,34 Taken together, we concluded that patients with short pouch were prone to achieve relatively poor pouch function and had more defecation frequency even incontinence, which could impair the improvement of QOL in the long run. Prospective research should be further performed to determine the results in the future.

Several limitations existed in this study. First, since it is a retrospective study, the loss of follow-up and clinical data is almost inevitable. A study with larger sample size is recommended to further demonstrate our results in the future. Second, some selective basis could exist since enrolled patients were managed by four inflammatory bowel disease surgery centers.

In this study, we found pouch length was associated with the clinical outcomes and long-term QOL improvement after IPAA. Patients with short J pouches were likely to achieve impaired long-term QOL and develop late postoperative complications, such as increased defecation frequency and pouchitis. We further demonstrated that short J pouch was an independent risk factor for the impaired long-term QOL and the development of late postoperative complications. Therefore, relatively long J pouch configuration could be a considerable surgical option for pouch construction. Multicenter prospective research with a large sample size should be performed to further demonstrate the results in this study.

This work was supported by the National Natural Science Foundation of China (No. 82000481 and 82270549), the Shanghai Sailing Program (No. 20YF1429400) and the Qingfeng Scientific Research Fund of the China Crohn’s & Colitis Foundation (CCCF) (No. CCCF-QF-2022C14-21).

No potential conflict of interest relevant to this article was reported.

Study concept and design: P.D., Z.D., W.Z. Data acquisition: W.X., W.T., W.D., Z.H., Y.W., X.G. Data analysis and interpretation: W.X. Drafting of the manuscript: W.X. Critical revision of the manuscript for important intellectual content: W.X., W.T., W.D. Statistical analysis: W.X. Obtained funding: W.X., P.D. Administrative, technical, or material support; study supervision: L.C., X.W. Approval of final manuscript: all authors.