Footnotes

• Funding This work was supported by a EULAR grant, under the EULAR prevalence survey of rheumatoid arthritis and spondyloarthropathy, endorsed by the EULAR Standing Committee of Epidemiology and Health Service Research.

• Competing interests None declared.

• Patient consent Obtained.

• Ethics approval Ethics Committee, Institute of Rheumatology, University of Belgrade, Serbia.

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