Rheumatoid arthritis in the northeastern area of the People's Republic of China and western Japan.

The clinical features of 134 consecutive hospitalized patients with rheumatoid arthritis in the northeastern area of the People's Republic of China and 251 consecutive hospitalized patients from western Japan were compared. A total of 91.8% of the Chinese patients were of Han nationality, while all of the patients from Japan were Japanese. The patients in the People's Republic of China showed more inflammatory articular disease and more frequent subcutaneous nodules than did the Japanese patients in the presence of a less elevated ESR value and less radiographic joint destruction. The clinical features of the patients of Han nationality and the Japanese did not change even after adjusting the patients' age and disease duration. The reasons for the contradictory features in the Chinese patients still remain to be clarified. This study is hopefully a first step in promoting more precise studies on rheumatoid arthritis in the People's Republic of China.