Accepted for Publication: February 8, 2013.
Published Online: May 13, 2013. doi:10.1001/jamainternmed.2013.962
Author Contributions:Study concept and design: Mallen, Thomas, Croft, and Peat. Acquisition of data: Mallen and Thomas. Analysis and interpretation of data: All authors. Drafting of the manuscript: Mallen, Thomas, Belcher, Rathod, and Peat. Critical revision of the manuscript for important intellectual content: Mallen, Thomas, Belcher, Croft, and Peat. Statistical analysis: Mallen, Thomas, Belcher, Rathod, and Peat. Obtained funding: Mallen, Croft, and Peat. Study supervision: Mallen, Thomas, Belcher, Croft, and Peat.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by Arthritis Research UK Primary Care Research Fellowship 16037 awarded to Dr Mallen. Dr Croft is a National Institute for Health Research senior investigator and member of the Medical Research Council Prognosis ReSearch Strategy (PROG-RES) Partnership.
Role of the Sponsor: Keele University had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Previous Presentation: This study was presented at the 40th Annual Meeting of the North American Primary Care Research Group; December 4, 2012; New Orleans, Louisiana.
Additional Contributions: Elaine Hay, MD, Jonathan Hill, PhD, and Kate Dunn, PhD, provided comments on the draft of the manuscript. We thank the participating patients and practices, and the Keele General Practice Research Partnership, and the administration and informatics team for assisting in the conduct of this study.