1. Systemic Autoimmune Diseases Unit, Hospital Universitario Virgen de las Nieves, Granada, Spain
2. Service of Internal Medicine, Hospital Universitario Virgen de las Nieves, Granada, Spain
3. Service of Prevention and Labour Health, Diputación de Granada, Hospital Xeral-Calde, Lugo, Spain
4. Department of Statistics, Hospital Universitario Virgen de las Nieves, Granada, Spain
5. Division of Rheumatology, Hospital Xeral-Calde, Lugo, Spain