Footnotes

• Contributors PSD: study concept and design; acquisition, analysis, review and interpretation of data; manuscript preparation and critical revisions. CAS: study concept and design; review and interpretation of data; manuscript preparation and critical revisions; study supervision. J-FC: review and interpretation of data; manuscript preparation and critical revisions. WJS: review and interpretation of data; manuscript preparation and critical revisions. LP-B: study concept and design; review and interpretation of data; manuscript preparation and critical revisions; study supervision.

• Competing interests CAS has served on the advisory board and as a consultant for Abbvie, Janssen, Takeda and UCB, and has received grant support from Abbvie, Janssen, and UCB. He has delivered CME lectures for Abbvie, Janssen and Merck. CAS is supported by Grant number 1R01HS021747-01 from the Agency for Healthcare Research and Quality. J-FC has served as consultant, advisory board member or speaker for Abbvie, ABScience, Amgen, Bristol Meyers Squibb, Celltrion, Danone, Ferring, Genentech, Giuliani SPA, Given Imaging, Janssen, Immune Pharmaceuticals, Merck & Co., Millenium Pharmaceuticals Inc., Nutrition Science Partners Ltd., Pfizer Inc. Prometheus Laboratories, Protagonsit, Receptos, Sanofi, Schering Plough Corporation, Second Genome, Takeda, Teva Pharmaceuticals, UCB Pharma, Vertex, Dr. August Wolff GmbH & Co. WJS has received consulting fees from Abbott, ActoGeniX NV, AGI Therapeutics Inc, Alba Therapeutics Corp, Albireo, Alfa Wasserman, Amgen, AM-Pharma BV, Anaphore, Astellas, Athersys Inc, Atlantic Healthcare Ltd, Aptalis, BioBalance Corp, Boehringer-Ingelheim, Bristol-Myers Squibb, Celgene, Celek Pharmaceuticals, Cellerix SL, Cerimon Pharmaceuticals, ChemoCentryx, CoMentis, Cosmo Technologies, Coronado Biosciences, Cytokine Pharmasciences, Eagle Pharmaceuticals, EnGene Inc, Eli Lilly, Enteromedics, Exagen Diagnostics Inc, Ferring Pharmaceuticals, Flexio Therapeutics Inc, Funxional Therapeutics Ltd, Genzyme Corp, Gilead Sciences, Given Imaging, GSK, Human Genome Sciences, Ironwood Pharmaceuticals, KaloBios Pharmaceuticals, Lexicon Pharmaceuticals, Lycera Corp, Meda Pharmaceuticals, Merck Research Laboratories, Merck Serono, Millenium Pharmaceuticals, Nisshin Kyorin Pharmaceuticals, Novo Nordisk, NPS Pharmaceuticals, Optimer Pharmaceuticals, Orexigen Therapeutics Inc, PDL Biopharma, Pfizer, Procter and Gamble, Prometheus Laboratories, ProtAb Ltd, Purgenesis Technologies Inc, Relypsa Inc, Roche, Salient Pharmaceuticals, Salix Pharmaceuticals, Santarus, Schering Plough, Shire Pharmaceuticals, Sigmoid Pharma Ltd, Sirtris Pharmaceuticals, SLA Pharma UK Ltd, Targacept, Teva Pharmaceuticals, Therakos, Tillotts Pharma AG, TxCell SA, UCB Pharma, Viamet Pharmaceuticals, Vascular Biogenics Ltd, Warner Chilcott UK Ltd and Wyeth; research grants from Abbott, Bristol-Myers Squibb, Genentech, GSK, Janssen, Milennium Pharmaceuticals, Novartis, Pfizer, Procter and Gamble, Shire Pharmaceuticals and UCB Pharma; payments for lectures/speakers bureaux from Abbott, Bristol-Myers Squibb and Janssen; and holds stock/stock options in Enteromedics. LP-B has received consulting fees from Merck, Abbott, Janssen, Genentech, Mitsubishi, Ferring, Norgine, Tillots, Vifor, Shire, Therakos, Pharmacosmos, Pilège, BMS, UCB-pharma, Hospira, Celltrion, Takeda, Boerhinger-Ingelheim, and Lilly; lecture fees from Merck, Abbott, Janssen, Ferring, Norgine, Tillots, Vifor, Therakos, and HAC-pharma.

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