Table 1.

Characteristics of the studies included in the meta-analysis.

References	Study design	Country	Sample size	Number of chronic pouchitis	Gender (M/F)	Mean age (years)	Type of surgery	Regression	Follow-up period
Abdelrazeq et al. (16)	Cohort study	UK	198	29	116/82	31.4	IPAA	Logistic regression	Mean 64 months (range 12–180)
Akiyama et al. (17)	Cohort study	Japan	392	125	224/168	32	IPAA	Logistic regression	Median 8.5 years (IQR 4.8–12.7)
Baek et al. (18)	Cohort study	Korea	232	74	133/99	37	IPAA	Cox univariate analysis	NR for total cohort; CP subgroup: median 99 months (IQR 44.8–164.5)
Barnes et al. (19)	Cohort study	USA	594	111	326/268	41.3	IPAA	Logistic regression	Up to 2 years
Bertucci Zoccali et al. (20)	Case-control	USA	411	166	240/171	36	IPAA	Logistic regression	Median 62 months
Ferrante et al. (21)	Cohort study	Belgium	172	80	105/67	39.1	IPAA	Logistic regression	Median 6.7 years (IQR 3.7–10.5)
Fleshner et al. (22)	Cohort study	USA	186	23	112/74	38	IPAA	Logistic regression	Median 24 months (range 3–117)
Gorrepati et al. (23)	Cohort study	USA	353	126	211/141	51.2	IPAA	Logistic regression	NR
Hashavia et al. (24)	Cohort study	Israel	201	63	106/95	35	IPAA	Logistic regression	Mean 107 months
Hata et al. (26)	Cohort study	Japan	58	9	30/28	32.1	IPAA	Logistic regression	NR
Hata et al. (25)	Cohort study	Japan	100	12	60/40	29.33	IPAA	Logistic regression	Median 125 months (range 5–251)
Kasashima et al. (27)	Cohort study	Japan	1,136	67	674/462	42	IPAA	Logistic regression	Median 77.6 months
Okita et al. (28)	Cohort study	Japan	231	31	128/103	29	IPAA	Logistic regression	Median 1,882.5 days (range 31–4,465)

CP, chronic pouchitis; IPAA, ileal pouch–anal anastomosis; IQR, interquartile range; NR, not reported.