Table 3

Comparison of data from five sources for consecutive patients with RA

Institution Period City Area Patients (n) Peak age at onset Mean disease duration (y)
Group I; Osaka University Hospital (Dept Orthop Surg)1960–1965Osakaurban56620s4.9
Group II; Shichikawa Arthritis Research Centre (Dept Rheumatol)1985–1990Hisairural36640s7.5
Osaka University Hospital (Dept Orthop Surg)1985–1990Osakaurban28640s5.7
Yukioka Hospital (Dept Rheumatol)1985–1990Osakaurban23340s
Osaka-Minami National Hospital (Dept Orthop Surg)1991–1994Kawachi-Naganosuburban37040s11.6