Table 1 Characteristics of identified studies

Kawalec et al. 2017 [14]

Poland

Patients with UC

N = 202

Disease duration 26.35 years

October 2015- Q1 2016

Van Der Valk et al. 2016 [15]

The Netherlands

IBD patients

N = 566

Disease duration 16 years

2 years

Malinowski et al. 2016 [16]

Poland

UC patients

N = 6900

NR

Aldeguer et al. 2016 [17]

Spain

Patients with UC

N = 285

12 months

Cohen et al. 2015 [18]

USA

UC patients

N = 1728

2 years (1 year baseline period and 1 year study period)

Van Der Valk et al. 2014 [19]

The Netherlands

IBD Patients

N = 937

Disease duration 13.3 years

3 months

Meek et al. 2013 [20]

USA

Patients with UC

N = 31,050

12 months

Cohen et al. 2012 [21]

USA

UC patients

N = 1754

2 years

Kostic et al. 2015 [22]

Serbia

Patients with UC

N = 53

NR

Van Der Valk et al. 2012 [23]

The Netherlands

Patients with IBD

N = 928

2 years

Cannon et al. 2011 [24]

NR

IBD patients

N = 72

NR

Gibson et al. 2008 [25]

USA

Patients with CD and UC

N = 8970

NR

Mandel M et al. 2014 [1]

Hungary

IBD patients

N = 183

Disease duration 9.9 years

NR

Katz Avitan et al. 2016 [2]

Israel

UC patients

N = 150

NR

Hellström et al. 2017 [26]

Sweden

UC patients

N = 1361

2 years

Neovius et al. 2010 [27]

Sweden

UC patients

N = 2914

NR

Stark et al. 2006 [28]

Germany

UC patients

N = 483

Disease duration 12 years

NR

Van Der Valk et al. 2015 [29]

The Netherlands

IDB patients

Pouch: n = 81

Mean age 46.7

Disease duration 15 years

For 2 years at 3 months intervals

Ileostomy: n = 48

Disease duration 18 years

Anti-TNFα: n = 34

Disease duration 16 years