Footnotes

• Contributors All authors made substantial contributions to the conception or design of the work; drafting the work or revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

• Competing interests PW has received grants from Ferring lægemidler and Tillotts Pharma as well as non-financial support from Janssen-Cilag A/S, Calpro AS, Pharmacosmos A/S and Vifor Pharma Nordiska AB. JH has received consulting or lecture fees from Abbvie, Celgene, Ferring, Hospira, Janssen, Medivir, MSD, Pfizer, RenapharmaVifor, Sandoz, Shire Takeda and Tillotts Pharma Research grants from Janssen, MSD and Takeda. Karolinska Institutet has received fees for lectures held by OO on occasions organised by Takeda and Ferring. Karolinska Institutet has received fees when OO participated as an expert in a panel discussing possibilities with register-based research. Karolinska Institutet (OO PI) performed an observational study, in part financed by an unrestricted grant from Janssen pharmaceuticals and one observational report financed by Pfizer. JB has received consulting fees from Celgene, Janssen-Cilag, Abbvie and Ferring, lecture fees from Abbvie, Pfizer, MSD and Takeda and has received an unrestricted grant from Takeda.

• Patient consent Not required.

• Provenance and peer review Not commissioned; internally peer reviewed.