Classic drugs in the time of new drugs: real-world, long-term outcomes of thiopurine monotherapy in 1016 patients with inflammatory bowel disease.

"Declaration of personal interests : MP reports grants and non‐financial support from Falk Pharma, grants from European commission, grants from ZonMw (Dutch national research fund), grants and non‐financial support from Takeda, grants and non‐financial support from Johnson and Johnson, grants and non‐financial support from Abbvie, non‐financial support from Ferring, non‐financial support from Immunodiagnostics, non‐financial support from MSD, all outside the submitted work. DJ reports grants from Top Knowledge Institute (Well on Wheat), grants from Horizon 2020 DISCOvERIE, grants from NWO‐CCC Partnership programme (Carbokinetics), all outside the submitted work. ZM reports grants form MLDS, Niels Stensen Fellowship and Galapagos. AvB has served as speaker, adviser and/or principal investigator for AbbVie, Arandal, Arena, Celgene, Ferring, Galapagos, Janssen, MSD, Pfizer, Roche, Takeda, TEVA and received research grants from Pfizer, TEVA, Eurostars funding, ZonMw, all outside the submitted work. The other authors have nothing to disclose relevant to this publication."

"FUNDING INFORMATION This work was in part supported by funding from the European Union Seventh Framework Programme (FP7/2012–2017, Grant number: 305564) as the IBDSL cohort involved in the Sysmed‐IBD consortium."

"All included patients in this multi‐centre retrospective cohort study originated from the population‐based IBD South‐Limburg (IBDSL) cohort. The IBDSL cohort is a longitudinal, population‐based, prospective inception cohort of adult IBD patients, which has been described previously. In brief, this inception cohort was initiated in 1991 and contains all newly‐diagnosed patients with IBD from the age of 18 years and older living in the South Limburg region (the Netherlands). As a result of a multi‐faceted identification strategy and joint cooperation of all regional hospitals (Maastricht University Medical Center, and Zuyderland Medical Centre Heerlen and Sittard), the cohort comprises at least 93% of all patients with IBD in the South Limburg region. In the present study, 2825 IBD patients (1663 UC, 1162 CD) were available for analysis. All patients were prospectively followed from the date of diagnosis to the end of current data collection (2014), date of migration out of area or death. The IBDSL study design has been approved by the Ethics Committee of Maastricht University Medical Center (NL31636.068.10), follows the declaration of Helsinki, and is registered in ClinicalTrial.gov (NCT02130349). "