[1] Inst Mexicano Seguro Social, Unidad Invest Med, Unidad Med Alta Especialidad, Merida 97150, Yucatan, Mexico
[2] Hosp Gen Mexico City, Dept Rheumatol, Mexico City, DF, Mexico
[3] Univ Autonoma Chihuahua, Chihuahua, Mexico
[4] Inst Nacl Salud Publ, Merida, Venezuela
[5] Gen Hosp Dr Miguel Silva, Res Unit Dr Mario Alvizouri Munoz, Secretaria Salud, Morelia, Michoacan, Mexico
[6] Reg Gen Hosp, Rheumatol Serv, Inst Mexicano Seguro Social, Merida, Yucatan, Mexico
[7] Mexican Coll Rheumatol, Res Unit, Mexico City, DF, Mexico