1. Rheumatology Department, Hospital de Especialidades Dr Antonio Fraga Mouret, Mexico City, Mexico
2. Hospital General Regional No. 1, Charo, Mexico
3. Instituto de Investigación en Reumatología y del Sistema Músculo-esquelético, Universidad de Guadalajara, Guadalajara, Mexico
4. Direction of Epidemiology, Hospital de Especialidades Dr Antonio Fraga Mouret, Mexico City, Mexico
5. Direction of Education and Research, Hospital de Especialidades Dr Antonio Fraga Mouret, Mexico City, Mexico