[1] Hokkaido Univ, Grad Sch Med, Div Rheumatol Endocrinol & Nephrol, Sapporo, Hokkaido, Japan
[2] Aomori Prefectural Cent Hosp, Dept Rheumatol, Aomori, Japan
[3] Takikawa Municipal Hosp, Dept Internal Med, Takikawa, Hokkaido, Japan
[4] Tohoku Univ, Grad Sch Med, Dept Hematol & Rheumatol, Sendai, Miyagi, Japan
[5] Tomakomai City Hosp, Dept Internal Med, Tomakomai, Japan
[6] Hokkaido Med Ctr Rheumat Dis, Sapporo, Hokkaido, Japan
[7] Hokkaido Orthopaed Mem Hosp, Dept Rheumatol & Orthopaed Surg, Sapporo, Hokkaido, Japan
[8] Higashisendai Rheumat Dis Clin, Sendai, Miyagi, Japan
[9] Kin Ikyo Chuo Hosp, Div Rheumatol, Sapporo, Hokkaido, Japan
[10] Tonan Hosp, Ctr Rheumat Dis, Sapporo, Hokkaido, Japan
[11] Izumi Himawari Clin, Sendai, Miyagi, Japan
[12] NTT Sapporo Med Ctr, Rheumatol, Sapporo, Hokkaido, Japan
[13] Sapporo Kiyota Hosp, Sapporo, Hokkaido, Japan
[14] NTT Sapporo Med Ctr, Sapporo, Hokkaido, Japan