Author Contributions: Drs Heijstek and Wulffraat had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Heijstek, Berbers, Wulffraat.
Acquisition of data: All authors.
Analysis and interpretation of data: Heijstek, Smits, van Gageldonk, Berbers, Wulffraat.
Drafting of the manuscript: Heijstek, Wulffraat.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Heijstek, de Vries, Wulffraat.
Obtained funding: Wulffraat.
Administrative, technical, or material support: Heijstek, de Vries, Smits, van Gageldonk, Berbers, Wulffraat.
Study supervision: Wulffraat.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Wulffraat reports that he has received a research grant for the current study from the Dutch League Against Rheumatism through his institution; research grants from Roche and AbbVie through his institution; honoraria and institutional compensation from Roche, Novartis, and Pfizer for serving as a consultant; and compensation from Novartis for advisory board membership. No other disclosures were reported.
Funding/Support: The Dutch Arthritis Association (project 07-02-403) funded this study.
Role of the Sponsor: The sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or decision to submit the manuscript for publication.
Additional Contributions: We thank all of the patients who volunteered for the study; Marjolein Musbach, BS, research manager at the University Medical Center Utrecht, for trial coordination; Paul Westers, PhD, Julius Center, University Medical Center Utrecht, for his expert assistance in the statistical analyses; and Linda McPhee, MA, for editorial assistance. The individuals acknowledged received no compensation for their contributions.